Immunology ASCP MLT medialab exams

Removal of which of these organs may be a last resort treatment for a patient whose platelet count is less than 30 x 109/L as a result of chronic idiopathic thrombocytopenic purpura (ITP)? - Gall bladder - Pancreas - Spleen - A kidney

- Spleen In ITP, antibodies develop that coat the platelets. The spleen produces macrophages whose Fc receptors recognize and destroy these antibody-coated platelets. Removing the spleen would decrease platelet destruction, but it is a last resort since the immunologic function of the spleen would also be lost. Removing the gall bladder, pancreas, or a kidney would not improve thrombocytopenia caused by ITP.

Within what period of time after performance of the tuberculin skin test (TST) should the result be read? - Immediately - 12-24 hours - 48-72 hours - 5-7 days

- 48-72 hours The skin test for exposure to tuberculosis (TB) is an example of a type IV hypersensitivity reaction (delayed hypersensitivity reaction). A small amount of antigen is injected under the skin. The result is read 48 - 72 hours after the intradermal injection to look for the presence of a lesion greater than or equal to 10 mm in diameter. This result would indicate the possibility that the individual was exposed to Mycobacterium tuberculosis. Individuals who have strongly positive reactions, a skin test diameter greater than 15 mm, and symptoms suggestive of TB should be evaluated clinically and microbiologically. Two sputum specimens collected on successive days should be investigated for TB by microscopy and culture.

In an standard electrophoretic separation, what zone appears first (anodal end) on the densitometric pattern? - Albumin - a 1-globulins - a2-globulins - ß-globulins

- Albumin Using standard serum protein electrophoresis methods, serum proteins separate into five bands in the following order: albumin travels farthest toward the anode followed by a1-globulins, a2-globulins, ß-globulins, and gamma-globulins.

Which T lymphocyte expresses the CD8+ marker and acts specifically to kill tumor or virally-infected cells? - Helper T lymphocytes - T reg lymphocytes - Natural killer - T cytotoxic

- T cytotoxic T-lymphocyte subset divisions are not absolute, with considerable overlap or redundancy in function among the different subsets. T-cells with the CD8 marker (also known as cytotoxic T cells) belong to a sub-group of T lymphocytes that are capable of directly destroying virally infected target cells Most cytotoxic T lymphocytes are CD8+ and recognize antigen on the target cell surface associated with MHC class I molecules, e.g., HLA types A, B, and C or MHC class I alone. This process is demonstrated by the immune response to virus-infected cells or tumor cells. Helper T lymphocytes can be assigned to three CD4+ subsets: TH1, TH2, and TH17. These subsets play a critical role in orchestrating the adaptive immune response. They exert their influence by secreting cytokines and chemokines that activate and/or recruit target cells. T reg lymphocytes are immunoregulatory TH cells that control autoimmunity in the peripheral blood through dominant tolerance. These cells can be natural or induced. A third major population of lymphocytes that uses different strategies to discriminate self from non-self is the natural killer (NK) population of circulating lymphocytes, about 10%. The NK cells lack the conventional antigen receptors of T or B lymphocytes.

Which of the following tests is used to confirm a syphilis infection after another method tests positive for syphilis? - Rapid Plasma Reagin (RPR) test - Veneral Disease Research Laboratory (VDRL) test - Dark-filed examination - T. pallidum particle agglutination (TP-PA) test

- T. pallidum particle agglutination (TP-PA) test TP-PA is a treponemal test used to confirm a previous positive method for syphilis. Such methods include dark-field microscopy of exudates from skin lesions, and nontreponemal serological tests such as RPR and VDRL.

What is the half-life of IgG? Why is the duration of the half-life significant? - 1-3 days; it is the first antibody produced in an immune response. - 5-6 days; it participates in an immediate hypersensitivity reaction. - 18-23 days; it is important for B-cell activation and/or regulation. - 18-23 days; it binds with neonatal Fc receptor.

- 18-23 days; it binds with neonatal Fc receptor. The half-life of IgG is 18-23 days; it binds with neonatal Fc receptor ( FcRn). IgG has a long half-life (with the exception of IgG on mast cells with a half-life of 90 days). The long IgG half-life is attributed to its ability to bind to the specific Fc receptor FcR called the neonatal Fc receptor. This receptor is involved in the transport of IgG from the maternal circulation across the placental barrier and the transfer of maternal IgG across to the intestine in neonates. FcRn structurally resembles MHC class I molecules. IgM has a half-life of 1-3 days; it is the first antibody produced in an immune response. IgE has a half-life of 5-6 days; it participates in an immediate hypersensitivity reaction. IgD has a half-life of 18-23 days; it is important for B-cell activation and/or regulation.

Which of the following kappa / lambda ratios are found in normal B cells? - 4 : 1 - 3 : 1 - 2 : 1 - 1 : 1

- 2 : 1 The normal ratio of B cells producing kappa chains versus those producing lambda chains is approximately 2:1. A kappa/lambda ratio outside of the 2:1 ratio is an indication of a monoclonal gammopathy such as multiple myeloma.

When should acute and convalescent blood specimens be collected from a patient for the detection of antibody concentration related to a specific infectious disease? - 2 weeks apart - 4 weeks apart - 3 months apart - 6 months apart

- 2 weeks apart In obtaining specimens for serologic testing, it is important to consider the phase of the disease and the condition of the patient at the time of specimen collection. This is especially important in assays for the diagnosis of infectious diseases. If patient serum is being tested for the concentration (titer) of antibodies for a specific infectious organism, a blood specimen should be drawn and the serum frozen during the acute phase of the illness (when the disease is first discovered or suspected), and a second blood sample drawn during the convalescent phase, usually about 2 weeks later. A difference in the antibody titer may be noted when the two different samples are tested concurrently. In general, 4 weeks is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 3 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 6 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). However, some infectious diseases, such as Legionnaire's disease or hepatitis, may not manifest a rise in titer until months after the acute infections.

The term TITER (as it applies to the measurement of antibodies) is best defined as: - Concentration of antibody in the serum - Maximum reactive dilution X 100 - Maximum reactive dilution / 100 - Reciprocal of maximum reactive dilution

- Reciprocal of maximum reactive dilution The term TITER (as it applies to the measurement of antibodies) is best defined as reciprocal of maximum reactive dilution of the patient's serum where the antibody is still detectable. For example, a specimen with a last reacting tube containing a 1:100 dilution, would be said to have a titer of 100.

Characteristics of Type I cryoglobulins include the following characteristics: - Contains two classes of immunoglobulins, at least one of which is monoclonal - Mixed, no monoclonal protein found - Monoclonal IgG, IgA, or IgM - Contains five classes of immunoglobulins.

- Monoclonal IgG, IgA, or IgM Type I cryoprecipitate is a monoclonal IgG, IgA or IgM Type II cryoprecipitate is mixed, containing two classes of immunoglobulins, at least one of which is monoclonal. Type III cryoprecipitate is mixed and no monoclonal protein is demonstrated. None of the types of cryoprecipate contains five classes of immunoglobulins.

Which of the following markers would you expect to find in the serum of a patient who has recently recovered from Hepatitis B infection? - Anti-HBs - HBsAg - HBeAg - HCVAb

- Anti-HBs The anti-HBs antibody is produced in response to the hepatitis B surface antigen and indicates immunity to the Hepatitis B virus. Anti-HBs levels rise during recovery from hepatitis B infection and can remain elevated for years thereafter. Thus, anti-HBs can be used to detect previous exposure to HBV or to detect a successful response to the hepatitis B vaccine. HBsAg (Hepatitis B surface antigen) and HBeAg (Hepatitis Be antigen) are components of the hepatitis B virus that circulate in the blood during the infection. HCVAb is the antibody produced in response to hepatitis C infection, not hepatitis B.

Which of the following statements is true regarding anti-nuclear antibodies? - They are highly specific for patients with systemic lupus erythematosus - 95% of patients with SLE will test positive for ANAs - Reactions using HEp-2 cells will demonstrate diffuse, speckled, peripheral and starburst patterns - Results are diagnostic with no further testing necessary

- 95% of patients with SLE will test positive for ANAs ANAs can be found in several conditions including Rheumatoid arthritis, Scleroderma and Sjögren's syndrome. 95% of patients will test positive for ANAs as patients are creating autoantibodies that react to different nuclear, nucleolar and perinuclear antigens like nucleic acids, histones, chromatin and nuclear anti-ribonuclear proteins. While diffuse, specked and peripheral patterns are found in FANA testing with HEp-2 cells there is no pattern identified as starburst. Because there are several other autoimmune conditions that will have positive ANAs further confirmatory testing is required, and usually ELISA testing is performed.

Severe combined immunodeficiency (SCID) is characterized by all of the following immunodeficiencies EXCEPT: - T-cell reduction or dysfunction - B-cell reduction or dysfunction - Natural killer (NK) cell reduction - A deficiency of stem cells

- A deficiency of stem cells SCID has multiple genetic causes. Two modes of genetic inheritance can be X-linked or autosomal recessive. No important differences in signs and symptoms exist between the two major genetic types of SCID. Although the list of gene defects is extensive in SCID, the defects can be stratified according to markedly decreased circulating T-lymphocytes or absence of T-cell function with or without the loss of B- and NK-cell host defenses Inappropriate development of stem cells does not characterize SCID. T-cell reduction or dysfunction. SCID is caused by numerous molecular defects that lead to severe compromise in T-cell reduction or dysfunction, B cell reduction or dysfunction . and occasionally reduction in the number of natural killer (NK) cells. Without intervention, SCID usually results in severe infection and death in children by age 2 years. SCID is characterized by blocking T-lymphocyte differentiation or function and can be associated with abnormal development of other types of lymphocytes (B-cells and NK-cells) Moderate lymphocytopenia is detectable early in infancy in SCID patients. However, the circulating blood contains no CD4+, CD8+, or CD3+ cells. B-cell reduction or dysfunction. B-cell depletion reduction or dysfunction can exist in SCID. The percentage of B cells is usually normal. Patients with the X-linked form of SCID usually appear to have similar characteristics. However, patients with the autosomal-recessive-form tend to have an increased percentage of B cells. Variable hypogammaglobulinemia is expressed with decreased serum IgM and IgA. Natural killer (NK) cell reduction. Three instances of SCID genetic mutations (IL2RG, JAK3, ADA) express decreased numbers of natural killer (NK) cells and decreased or absent circulating T-cells. Normal or increased circulating B-cells are reported if the gene mutation is IL2RG or JAK3 but in an ADA mutation circulating B-cells are absent from birth or progressively decrease.

A hapten can BEST be described as: - A carrier molecule for an antigen that is not antigen alone - A nonimmunogenic material capable of stimulating an immune response only when bound to a carrier protein - An immunoglobulin functional only in the presence of complement - Half of an immunoglobulin molecule

- A nonimmunogenic material capable of stimulating an immune response only when bound to a carrier protein A hapten is a low molecular weight molecule that can elicit an immune response only when attached to a large carrier such as a protein. A carrier can stimulate B cells itself, but a hapten cannot. When bound to a hapten, the carrier creates a large complex that can activate B cells to respond to the hapten as well by cross-linking their receptors. Haptens are incomplete antigens; they are not immunoglobulins or part of an immunoglobulin.

According to the HIV testing algorithm from the CDC, all of the following statements are true, EXCEPT: - A nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. - As part of initial screening, an HIV-1/2 antigen/antibody combination immunoassay should be performed. - An HIV-1/2 antibody differentiation immunoassay should be used to differentiate a positive screening test. - HIV-1 NAT testing should only be used to resolve any discrepant results between initial reactive testing and nonreactive follow-up testing.

- A nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. The correct answer is a nonreactive screening test to either HIV-1 or HIV-2 is confirmation that a patient does not have HIV. A nonreactive result must be obtained for both HIV-1 and HIV-2, as well as the p24 antigen, in order to consider a patient negative for HIV. This CDC algorithm allows for earlier detection of infections and overcomes the limitations associated with the use of the western blot test. As part of initial screening, an HIV-1/2 antigen/antibody combination immunoassay should be performed. An HIV-1/2 antibody differentiation immunoassay should be used to differentiate a positive screening test. HIV-1 NAT testing should only be used to resolve any discrepant results between initial reactive testing and nonreactive follow-up testing.

Prozone is observed in: - Serially diluted tubes of serum that contain the least concentration of antibody - In the zone of equivalence - A patient sample in which the serum contains a high titer of antibody - A patient sample in which the serum has been inactivated before testing

- A patient sample in which the serum contains a high titer of antibody Prozone is a phenomenon in which titers of specific antigen and antibodies do not agglutinate or precipitate visibly because of an excess in antibody. The antigen/antibody ratio is the number of antibody molecules in relation to the number of antigen sites per cell. Under conditions of decreased antigen/antibody ratio, an antibody excess may exist. The outcome of excessive antibody concentration is known as the prozone phenomenon, which can produce a false-negative reaction. This phenomenon can be overcome by serially diluting the antibody-containing serum until optimum amounts of antigen and antibody are present in the test system. Serially diluted tubes of serum that contain the least concentration of antibodies do not exhibit a pro-zone reaction. The post-prozone range of weaker dilutions no longer exhibits visible agglutination. An excess of antigen occurs, resulting in no lattice formation in an agglutination reaction. The zone of equivalence is the range of dilutions where the relative concentration of antibody and antigen produce maximal binding of antigen to antibody. In the zone of equivalence, agglutination is observable. A patient sample in which the serum has been inactivated before testing would not contribute to prozone. Heating serum at 56 degrees is used to inactivate complement in several immunological assays. During heating, both heat-labile and heat-stable anticomplementary activity (ACA) develop. ACA can be completely inactivated. Heat-stable ACA develops in deaggregated IgG and in normal, but not in hypogammaglobulinemic, human, and porcine serum heated at 56 degrees suggesting that this ACA is due to formation of immunoglobulin aggregates. These aggregates would produce false-positive tests for immune complexes and could inhibit a variety of cell-mediated reactions in assays that incorporate heat-inactivated serum.

A cytokine can be described as: - A soluble protein that regulates the immune response - A chemical messenger that is only produced by lymphocytes - A substance that acts alone to influence an immune response - An antibody that reacts with lymphocytes

- A soluble protein that regulates the immune response Cytokines are soluble proteins that regulate the innate and adaptive immune responses to an antigen. They are produced by white blood cells and other cell types, and act in conjunction with other cytokines to generate a network of interactions that influences an immune response. Cytokines are different from antibodies, which are proteins produced by B lymphocytes that specifically react with an antigen.

Significant risk factors for potential development of graft-versus-host disease (GVHD) include the following factors except: - Source of immunocompetent lymphocytes - Human leukocyte antigen (HLA)differences - Inability to reject donor lymphocytes - A strong ability of the host to destroy foreign lymphocytes

- A strong ability of the host to destroy foreign lymphocytes A strong ability of the host to destroy foreign lymphocytes. In immunocompromised patients, the transfused or grafted lymphocytes recognize the antigens of the host as foreign and react immunologically against them. Instead of the usual transplantation reaction of a host patient against graft, the reverse GVHD occurs. The source of immunocompetent lymphocytes is a factor in the potential development of GVHD. Recipients of bone marrow or hematopoietic stem cells transplant have an increased risk of developing chronic graft-versus-host disease (cGVHD). Human leukocyte antigen (HLA) differences are a factor in the potential development of graft-versus-host-differences (GVHD). Mismatches in HLA antigens between the donor and the recipient increase the risk of developing cGVHD. Severely immunocompromised or immunosuppressed patients are unable to reject donor cells. This increasing their susceptibility for developing GVHD.

Which two of the following tests are helpful for documenting previous streptococcal throat and skin infections? - ASO titer & anti-DNase B - CAMP & PYR - Coagulase & catalase - Bacitracin & SXT

- ASO titer & anti-DNase B Individuals with disease caused by Streptococcus pyogenes produce antibodies against various antigens. The most common are antistreptolysin O (ASO), anti-DNAse B, antistreptokinase, and antihyaluronidase. Use of serodiagnostic tests is most useful to demonstrate prior streptococcal infection in patients. CAMP & PYR are used to identify group B or group A streptococci. The CAMP test will be positive for group B (S. agalactiae) streptococci and the PYR will be positive for group A (S. pyogenes) streptococci. Once an isolate is identified as, or strongly suspected to be, a species of staphylococci, a test for coagulase production is performed to separate Staphylococcus aureus from other species. The Staphylococcus spp. are distinguishable from the related family Streptococcaceae by the catalase test. For isolating group A streptococci from throat swabs, the most common medium is 5% sheep blood agar supplemented with trimethoprimsulfamethoxazole (SXT), to suppress the growth of normal microbiota. A bacitracin disc is placed on the initial inoculum streak to aid in identification (S. pyogenes will show sensitivity).

What form of immunity is expected to provide long-term protection after hepatitis B vaccine (HBV) is administered to an immunocompetent person? - Active - Passive - Adaptive - Innate (Natural)

- Active Active immunity can be acquired by natural exposure in response to an infection or a natural series of infections, or through intentional inject of an antigen. Vaccination is an effective method of stimulating antibody production and immunologic memory (acquired resistance) without contracting the disease in immunocompetent patients. Immunocompetency is the ability of a patient (host) to recognize a foreign antigen and build specific antigen-specific antibodies that result in permanent antigenic memory. More than one initial vaccination (a series) may be needed and booster vaccinations may be needed in some cases to expand the pool of memory cells. Passive immunity can be artificially or naturally acquired. Artificial passive immunity is achieved by infusion of serum or plasma containing high concentrations of antibody or lymphocytes from an actively immunized individual. Passive immunity via preformed antibodies in serum provides immediate, temporary antibody protection against microorganisms such as hepatitis A. Passive immunity can be acquired naturally by the fetus through the transfer of antibodies thru the maternal placental circulation in utero during the last 3 months of pregnancy. The amount and specificity of maternal antibodies depend on the mother's immune status to infectious diseases that she has experienced. Adaptive immunity is a type of body defense. If a microorganism overwhelms the body's natural, innate resistance, a third line of defense exists, adaptive immunity. Characteristics of adaptive immunity compared to innate immunity include: presence of memory lymphocytes, the physical barrier of lymphocytes in epithelial cells, antibodies secreted at epithelial surfaces, the presence of specific antibodies, and the action of lymphocytes. Natural immunity (inborn or innate resistance) is one of the ways that the body resists infection after microorganisms have penetrated the body's first line of defense of unbroken skin and mucus membranes. Characteristics of innate immunity include: absence of lymphocytes, skin and mucosal epithelial as physical barriers, presence of antimicrobial chemicals, the presence of complement, and the protective actions of macrophages, neutrophils, and natural killer cells.

The type of graft rejection that occurs from approximately 1 to 3 weeks after tissue or organ transplantation is: - Hyperacute - Accelerated - Acute - Chronic

- Acute Acute rejection of an organ or tissue occurs from 7 to 21 days after transplantation. The predominant mechanism is cell-mediated, possibly antibody cell-mediated cytotoxicity. The cause of rejection is the development of an allogeneic reaction to donor antigens. Acute rejection can result after the first exposure to alloantigens. In this reaction, donor antigens select reactive T-cell clones and initiate visible manifestation of rejection. Although the early processes in this type of rejection appear to be T-cell mediated, later aspects may involve antibodies and complement. Hyperacute rejection of an organ or tissue occurs within minutes after transplantation. The predominant mechanism is humor antibodies. The cause is preformed cytotoxic antibodies in the host to donor tissue cellular antigens. The antibodies are usually anti-A-related or anti-B-related antibodies to the ABO blood group systems or antibodies to class I MHC antigens (hypersensitivity type II). Accelerated rejection of an organ or tissue occurs 2-5 days after transplantation. The predominant mechanism is cell-mediated. The cause is previous sensitization to donor antigens. Accelerated rejection is caused by activation of the T-cell-mediated response. Chronic rejection of an organ or tissue occurs later than 3 months after transplantation. The predominant mechanism is cell-mediated. The cause is the disturbance of host-graft tolerance. Chronic rejection occurs in most graft recipients. It is a slow but continual loss of organ function over months or years. Chronic rejection is often responsive to various immunosuppressive therapies.

Given the following hepatitis B serology results, what is the immune status of the patient? HBsAg: positive HBeAg: positive Anti-HBc IgM: positive Anti-HBs: negative - Acute infection - Chronic infection - Immune to infection - Past infection

- Acute infection The combination of test results indicate an acute hepatitis B infection. HBsAg (hepatitis B surface antigen) is positive in both acute and chronic Hepatitis B infections, since the antigen is found on the actual surface of the virus. HBeAg (hepatitis Be antigen) is present in the blood when the hepatitis B viruses are replicating, indicating an active infection. Anti-HBc IgM (IgM antibody to the hepatitis B core antigen) is present during an acute or recent acute infection. Anti-HBs (antibody to the hepatitis B surface antigen) is produced during recovery from hepatitis B. This antibody can persist for years after the infection has occurred and provides immunity to the hepatitis B virus.

The characteristics of an acute phase protein include the following EXCEPT: - An acute phase response is a non-specific indicator of an inflammatory response. - Acute phase proteins are synthesized slowly in response to tissue injury. - C-reactive protein is an acute phase protein. - Laboratory measurement of an acute phase can be used to monitor the progress of therapy in inflammatory diseases.

- Acute phase proteins are synthesized slowly in response to tissue injury. 'Acute-phase proteins are synthesized slowly in response to tissue injury is the correct answer. The majority of acute-phase proteins are synthesized rapidly in response to tissue injury, e.g., inflammation, infection, malignant neoplasia, trauma, surgical procedures, or drug responses. Acute-phase proteins have different kinetics and various degrees of increase. The elevation is twofold to five-fold in certain disease states. A group of glycoproteins associated with the acute-phase response is collectively called acute-phase proteins of acute-phase reactants. More than 20 acute-phase proteins have a definable role in inflammation. An acute-phase response is a non-specific indicator of an inflammatory response. C-reactive protein (CRP) is an acute-phase protein. CRP is prominent among the acute-phase proteins because its changes show great sensitivity. Changes in CRP are independent of other laboratory tests, such as the erythrocyte sedimentation rate, and parallel the inflammatory process. CRP returns to lower undetectable levels as inflammation subsides. Laboratory measurement of an acute phase can be used to monitor the progress of therapy in inflammatory diseases. The acute-phase protein, CRP, is used clinically for monitoring infection, autoimmune disorders, and, more recently, healing after a myocardial infarction.

The name of a reaction between a single antigenic determinant and an individual combining site is: - Affinity - Avidity - Reactivity - Structural stability

- Affinity Affinity is the name of the bond between a single antigenic determinant and an individual combining site. Affinity is the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope or determinant site on the corresponding antigen. The antigen is univalent and is usually a hapten. Several types of noncovalent bonds hold an epitope and binding site close together. Avidity is the strength with which a multivalent antibody binds to a multivalent antigen. This avidity can result when an antigen, e.g., hapten, has only one antigenic determinant (monovalent). The total functional strength of all interactions between an antibody and its specific antigen is called avidity. Based on the heavy-chain isotype, antibodies can have 2 to 10 antigen-binding sites. When a multivalent antigen combines with more than one of an antibody's combining sites, the strength of the bonding is significantly increased. For the antigen and antibody to dissociate, all the antigen-antibody bonds must be broken simultaneously. Decreased avidity can result when an antigen, e.g., hapten, has only one antigenic determinant (monovalent). Reactivity is the description of an antigen-antibody reaction that is a reversible binding of antigen to homologous antibody by the formation of weak bonds between antigenic determinants on antigen molecules and antigen-binding sites on immunoglobulin molecules. Structural stability is a characteristic of an effective antigen. Unstable or inert molecules are poor antigens. The structural stability of an antigen is important where the goal is to elicit a patient antibody response when administering a vaccine.

All of the following are applications of real-time PCR, EXCEPT? - Microbe identification - Genotyping HLA components - Idenfication of DNA sequences - Amplification of DNA for northern blot

- Amplification of DNA for northern blot The amplification of DNA for northern blot is not an application of real-time PCR. Northern blotting is a hybridization method that can be used to detect specific RNA sequences. Real-time PCR can be used to identify microbes that are difficult to grow in laboratory conditions, genotyping for HLA components for donor and recipients in transplantation, identifying specific DNA sequences for particular HLA genotype, amplification of stretches of RNA and more.

The enzymatic process in each Polymerase Chain Reaction (PCR) cycle consists of the following steps EXCEPT: - DNA denaturation - Primer annealing - Extension of primed DNA sequence - Analysis of PCR product

- Analysis of PCR product Analysis of the PCR product completed in the same tube can be analyzed in various ways after PCR cycling is completed. Typically, the contents of the reaction vessel are subjected to gel electrophoresis. This allows visualization of the amplified gene segments, e.g., PCR products, and analysis of their specificity. Additional product analysis by probe hybridization or direct DNA sequencing is often performed to further verify the authenticity of the amplicons. DNA denaturation is the first step in the enzymatic process of the Polymerase Chain Reaction (PCR) technique. The double DNA strands are separated into two single strands through the use of heat. Primer annealing is the second step in the enzymatic process of the Polymerase Chain Reaction (PCR) technique. The oligonucleotide primers are recombined with the single-stranded original DNA. The extension of primed DNA sequence is the last step in the enzymatic process of the Polymerase Chain Reaction (PCR) technique. The enzyme DNA polymerase synthesizes new complementary strands by the extension of primers.

Twelve weeks after onset of the disease, patients with uncomplicated acute hepatitis B usually will demonstrate which of the following in their serum? - HBsAg - Anti-EBNA - Anti-HBe - Anti-HIV

- Anti-HBe The Hepatitis B e-antigen, or HBeAg, is a viral protein associated with HBV infections. Unlike the surface antigen, the e-antigen is found in the blood only when there are viruses also present. Anti-HBe is an antibody produced in response to the Hepatitis B e-antigen. In those who have recovered from acute hepatitis B infection, anti-HBe will be present along with anti-HBc and anti-HBs. HBsAg or Hepatitis B surface antigen is the first measurable sign of infection with Hepatitis B. As the disease progresses, the antigen disappears and antibodies begin to form. If the HBsAg was still present at 12 weeks post infection, the patient would be classified as a chronic carrier status and not as acute hepatitis. Anti-EBNA is antibody to the nuclear antigen for Epstein-Barr Virus (EBV). This antibody would be specific for Epstein-Barr virus infections and would indicate the patient has recovered from an infection with EBV. This antibody is not related to Hepatitis B. Anti-HIV is antibody to Human Immunodeficiency Virus (HIV). The antibody is produced 30-60 days after exposure to the virus and antibodies are typically still present 3 months after infection. Detectable antibodies to HIV is called seroconversion. This antibody is not related to Hepatitis B.

A physician suspects his patient might have rheumatoid arthritis. Which of the following markers should be ordered? - Antimitochondrial antibodies - Anti-IgG - Antineutrophilic antibodies - Antimyocardial antibodies

- Anti-IgG Rheumatoid arthritis commonly presents with an increase of IgM antibodies that are directed toward the Fc portion of IgG. These anti-IgG antibodies are called rheumatoid factor (RF). Patients with primary biliary cirrhosis will have an increase in antimitochondrial antibodies. Wegener's granulomatosis presents with antineutrophilic antibodies. Antimyocardial antibodies are important markers in patients who have rheumatic fever.

Which of the following is used to determine if a person has had a recent infection with Strep pyogenes? - Antistreptolysin O (ASO) - Hyaluronidase - M-protein - Streptococcal pyrogenic exotoxin

- Antistreptolysin O (ASO) ASO (antistreptolysin O titer) is a test that can be used to detect a recent infection with Strep pyogenes. The ASO is usually utilized to determine whether a previous Strep infection has caused a post-streptococcal disease, such as rheumatic fever, scarlet fever, or glomerulonephritis. Hyaluronidase, or spreading factor, is an enzyme present in Strep pyogenes that solubilizes the ground substance of connective tissues. Formerly, it was thought that it helped spread infection, but no evidence has been found to support this hypothesis. M-protein is attached to the cell wall of Strep pyogenes, and is essential for its virulence. Streptococcal pyrogenic exotoxins, formerly called erythrogenic toxins, are present in some strains of Strep pyogenes, and cause a red spreading rash, referred to as scarlet fever.

Which of the following autoantibodies would be usually found in a patient with Hashimoto's thyroiditis? - Thyroid-stimulating hormone receptor antibodies (TRAbs) - Antithyroid peroxidase (TPO) - Islet cell antibodies - Antitransglutaminase (tTG)

- Antithyroid peroxidase (TPO) Antithyroid peroxidase (TPO) antibodies are associated with Hashimoto's thyroiditis. They are found in about 95% of patients with Hashimoto's and are the best indicator if the disease.Thyroid-stimulating hormone receptor antibodies (TRAbs) are associated with Graves disease.Islet cell antibodies are associated with Type 1 diabetes mellitus.Antitransglutaminase (tTG) antibodies are associated with Celiac disease.

Which of the following autoantibodies are found in a patient with Hashimotos thyroiditis? - Thyroid-stimulating hormone receptor antibodies (TRAbs) - Antithyroid peroxidase (TPO) - Islet cell antibodies - Antitransglutaminase (tTG)

- Antithyroid peroxidase (TPO) While Antithyroid peroxidase (TPO) antibodies are associated with Hashimoto's thyroiditis and Graves disease, they are found in about 95% of patients with Hashimoto's and are the best indicator of the disease. Thyroid-stimulating hormone receptor antibodies (TRAbs) are associated with Graves disease. Islet cell antibodies are associated with Type 1 diabetes mellitus. Antitransglutaminase (tTG) antibodies are associated with Celiac disease.

The causative agent of infectious mononucleosis attaches to a receptor on which of the following cells? - T helper cell - B lymphocyte - T suppressor cell - NK cell

- B lymphocyte Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis, attaches to a receptor on B lymphocytes. Infectious mononucleosis is characterized by lymphocytosis with many reactive lymphocytes (usually >20%). On the clinical side of the infection, tiredness, headache, fever/chills, sore throat, and nausea are common symptoms. All other cells are lymphocytes but do not have the receptors to which EBV attaches itself.

Which of the following is responsible for the humoral immune response: - Neutrophils - Basophils - B lymphocytes - Monocytes

- B lymphocytes Humoral immunity involves antibody production. Most B lymphocytes participate in the humoral response through their transformation into plasma cells and secretion of antibodies. Other B cells become long-lived memory cells. Neutrophils are part of cellular immunity. Their major function is phagocytosis and destruction of foreign material and microorganisms. Basophil granules contain histamine, and they play a vital role in allergic reactions and the inflammatory response. Monocytes are phagocytic cells and recognize bacterial pathogens. While monocytes do present antigens to B-lymphocytes to initiate the adaptive immune response, it is the B lymphocyte that is responsible for the antibody production of the humoral immune response.

Most disorders associated with a primary immunodeficiency are _________ disorders. - T-cell disorders - B-cell disorders - Complement disorders - Platelet disorders

- B-cell disorders B-cell disorders rank as the most common primary immunodeficiency category. The distribution of B-cell disorders is approximately 53%. Because e the primary function of B cells is to produce antibodies, the major clinical manifestation of a B cell deficiency is an increased susceptibility to severe bacterial infections. Primary immunodeficiencies (PIDs) are rare genetic disorders of the innate and adaptive immune systems. More than 120 different gene mutations that cause impairment in the differentiation and function of immune cells have been identified, with different degrees of severity. PID disorders are predominantly seen (75%) in children younger than 5 years. T-cell deficiencies do not have a very high incidence of occurrence. The most common T cell deficiency states are those associated with a concurrent B cell abnormality. Partial T-cell immunodeficiency and immune dysregulation are characterized by elevated immunoglobulin E (IgE) production, an incomplete reduction in T-cell concentration or activity, autoimmunity, and inflammatory diseases. A deficiency of complement, an innate immune disorder, is uncommon. Deficiencies of complement account for a small percentage of primary immunodeficiencies (<2%). Other instances of primary immune disorders involving complement are very uncommon and include CH50 and AH50 disorders. Causes of primary immunodeficiency disorders include Selective, Combined, and Partial Combined immune deficiency disorders. A deficiency in this grouping is the partial combined immune deficiency disorder, Wiskott-Aldrich Syndrome (WAS). WAS is an uncommon x-line recessive gene defect. It is unique among primary immunodeficiencies because, in addition to being susceptible to infections, patients have problems with abnormal bleeding. WAS is characterized by smaller than normal size platelets and often a decreased number of platelets. In addition to a decreased platelet concentration, thrombocytopenia and increased susceptibility to bacterial, viral, and fungal infections are hallmark characteristics of WAS.

Which of the following tumor markers is widely used for the detection of colorectal cancers? - CEA - PSA - Alpha-fetoprotein - Beta hCG

- CEA CEA (carcinoembryonic antigen) is widely used as a tumor marker for colorectal cancer. It can also be elevated in lung, breast, and gastrointestinal tumors. CEA is also used for prognosis, in post-surgery surveillance, and to monitor response to chemotherapy.PSA (prostate specific antigen) is used as a prostate cancer marker. It is produced in the epithelial cells of the acini and ducts of the prostatic ducts of the prostate. AFP (alpha-fetoprotein) is used as a marker for hepatocellular carcinoma and germ cell tumors. It is made in the fetal liver and expressed in certain tumor types.hCG (human chorionic gonadotropin) can be used as a tumor marker for testicular cancer. It is normally secreted in the first trimester of pregnancy to promote implantation of the blastocyte and the placenta.

Most disorders associated with a primary immunodeficiency are _________ disorders. - T-cell disorders - B-cell disorders - Complement disorders - Platelet disorders

- B-cell disorders B-cell disorders rank as the most common primary immunodeficiency category. The distribution of B-cell disorders is approximately 53%. Because e the primary function of B cells is to produce antibodies, the major clinical manifestation of a B cell deficiency is an increased susceptibility to severe bacterial infections. Primary immunodeficiencies (PIDs) are rare genetic disorders of the innate and adaptive immune systems. More than 120 different gene mutations that cause impairment in the differentiation and function of immune cells have been identified, with different degrees of severity. PID disorders are predominantly seen (75%) in children younger than 5 years. T-cell deficiencies do not have a very high incidence of occurrence. The most common T cell deficiency states are those associated with a concurrent B cell abnormality. Partial T-cell immunodeficiency and immune dysregulation are characterized by elevated immunoglobulin E (IgE) production, an incomplete reduction in T-cell concentration or activity, autoimmunity, and inflammatory diseases. A deficiency of complement, an innate immune disorder, is uncommon. Deficiencies of complement account for a small percentage of primary immunodeficiencies (<2%). Other instances of primary immune disorders involving complement are very uncommon and include CH50 and AH50 disorders. Causes of primary immunodeficiency disorders include Selective, Combined, and Partial Combined immune deficiency disorders. A deficiency in this grouping is the partial combined immune deficiency disorder, Wiskott-Aldrich Syndrome (WAS). WAS is an uncommon x-line recessive gene defect. It is unique among primary immunodeficiencies because, in addition to being susceptible to infections, patients have problems with abnormal bleeding. WAS is characterized by smaller than normal size platelets and often a decreased number of platelets.In addition to a decreased platelet concentration, thrombocytopenia and increased susceptibility to bacterial, viral, and fungal infections are hallmark characteristics of WAS.

The mediator cell type that binds to IgE antibodies is the: - Basophil - Eosinophil - Polymorphonuclear neutrophil (PMN) - Macrophage

- Basophil Basophils have high concentrations of heparin and histamine in their granules, which play an important role in the acute system, hypersensitivity reactions. Degranulation occurs when an antigen such as pollen binds to two adjacent immunoglobulin E (IgE) antibody molecules located on the surface of mast cells. The events resulting from the release of the contents of these basophilic granules include increased vascular permeability, smooth muscle spasms, and vasodilation. If severe, this reaction can result in anaphylactic shock. Eosinophils are considered homeostatic regulators of inflammation. Functionally, this means that the eosinophil attempts to suppress an inflammatory reaction to prevent the excessive spread of the inflammation. Polymorphonuclear neutrophils (PMNs) are the principal leukocyte associated with phagocytosis and a localized inflammatory response. PMNs can prolong inflammation by the release of soluble substances, such as cytokines and chemokines. Macrophages and monocytes are phagocytic cells. Macrophages can be activated during infection by the release of macrophage-activating cytokines, e.g. interferon-gamma and granulocyte colony-stimulating factor from T lymphocytes. Macrophages exposed to an endotoxin release a hormone, tumor necrosis factor.

What can be done to make a hapten behave like an antigen? - Denature the protein - Bind to protein - Bind to lipid - Bind to carbohydrate

- Bind to protein A hapten is a very small (minute) molecule with a low molecular weight. Haptens are poor antigens by themselves. Large foreign molecules, specifically proteins, are effective antigens because of their large molecular weight. If a hapten is chemically linked to a large molecule such as a protein, a new surface structure is formed on the large molecule, which may function as an antigenic determinant. Important factors in the effective function of antigens include foreignness, degradability, molecular weight (MN), structural stability, and complexity. The more complex an antigen, the greater its effectiveness. Complex proteins are better antigens than repeating polymers, such as lipids, carbohydrates that are relatively poor antigens. Important factors in the effective function of antigens include degradability and structural stability. Denatured proteins are less effective because a sufficient amount of antigen is needed to stimulate an immune response. Bonding a hapten to a denatured protein would not make it function more effectively as an antigenic determinant. Important factors in the effective function of antigens include complexity: the more complex an antigen, the greater its effectiveness. Complex proteins are better antigens than repeating polymers, such as lipids, that are relatively poor antigens. Important factors in the effective function of antigens include complexity: the more complex an antigen, the greater its effectiveness. Complex proteins are better antigens than repeating polymers, such as carbohydrates, that are relatively poor antigens.

Which of the following organisms is best visualized by use of a darkfield microscope? - Poxviridae - Entamoeba - Borrelia - Streptococcus

- Borrelia Spirochetes such as Borrelia and Treponema are best visualized using darkfield microscopy. Borrelia, which causes Relapsing Fever, can be visualized under darkfield microscopy of wet preps of peripheral blood. Treponema can be visualized by darkfield microscopy of early primary lesions and aspirates of affected lymph nodes. Poxviridae is the largest and the most common of all viruses. The virions appear as oval or brick-shaped structures 200 to 400 nm in length. Because of their large size, poxvirus virions may be visualized through a light microscope. Good, clean microscopes and light sources are mandatory for examining specimens for parasites (e.g., Entamoeba). Organism identification depends on morphological differences, most of which can be seen using a stereoscopic microscope or a regular brightfield microscope. Streptococcus are typically round or oval-shaped and, when grown in broth, will show gram-positive cocci and the characteristic of growing in chains when viewed on the brightfield microscope.

Estrogen (ERs) and progesterone (PRs) receptors used as tumor markers are most commonly employed to provide prognostic information about: - Breast cancer - Uterine cancer - Menopause - Cervical cancer

- Breast cancer ERs and PRs receptors are used as tumor markers for breast cancer. Patients with tumors positive for both estrogen and progesterone receptors tend to respond favorably to hormonal therapy, whereas those without generally do not. Patients with positive estrogen and progesterone receptors also have a somewhat better prognosis.

Which of the following conditions is associated with the Epstein-Barr Virus? - Measles - Burkitt's lymphoma - Mumps - Chicken pox

- Burkitt's lymphoma Though the Epstein-Barr virus is usually associated with infectious mononucleosis, it can also cause human cancer, including Burkitt's lymphoma. The virus combines with acquired genetic mutations to produce disease. Measles is caused by the Rubeola virus. German measles is caused by Rubella virus. Mumps virus belongs to the Paramyxoviridae family. Chicken pox is caused by Varicella zoster.

Which complement component is found in both the classical and alternative pathways? - C1 - C4 - Factor B - C3

- C3 C3 is present in the plasma in the largest quantities; fixation of C3 is the major quantitative reaction of the complement cascade. The three pathways of the complement system, classic, alternative, and mannose-binding lectin, are initiated in various ways through different pathways. The three complement pathways converge at the point of cleavage of C3 to C3b, the central event of the common final pathway, which in turn leads to the activation of the lytic complement sequence, C5 through C9, and cell destruction. C1 is active in the initial phase of complement activation. The classic complement pathway is initiated by the bonding of the C1 complex, consisting of C1q, C1r, and C1s, to antibodies bound to an antigen on the surface of a bacterial cell. The C4 level often provides the most sensitive indicator of disease activity. C4 is an acute-phase reactant. Elevated C4 levels can indicate an acute inflammatory reaction of a malignant condition. C4 levels can be decreased with normal or increased C3 levels. Factor B is found in the alternative complement pathway. The factor B component is consumed by activation of the alternative complement pathway. A decreased level of factor B is associated with disorders such as hemolytic uremic anemia, atypical hemolytic uremic syndrome (HUS).

Which of the following is the "activation unit" in the classical complement pathway? - C1qrs - Factors B and D - C4, C2, C3 - C5, C6, C7, C8, C9

- C4, C2, C3 The classical pathway of complement can be divided into the recognition phase, activation phase, and membrane attack phase. In the first phase, the complement protein, C1, which consists of the C1q, C1r, and C1s subunits, binds to antigen-antibody complexes. In the second phase, fragments of C4, C2, and C3 combine to form the activation unit, which cleaves the C5 component of complement. Factors B and D participate in the alternative complement pathway, not the classical pathway. The components C5, C6, C7, C8, C9, combine in the final steps of the classical pathway to form the membrane attack complex, which binds to foreign cells, creating pores in the cell membranes that cause the cells to lyse.

Raynaud's phenomenon is associated with a deficiency/dysfunction of the complement fraction: - C2 - C5 - C7 - C8

- C7 A decreased level of the complement fraction, C7, is associated with Raynaud's disease, sclerodactyly, telangiectasia, and several bacterial infections caused by Neisseria spp. Raynaud's phenomenon is a condition of episodic constriction of small arteries of the extremities, usually fingers or toes, induced by cold temperatures or emotional stress that would not affect a non-afflicted person. Deficiencies of complement account for a small percentage of primary immunodeficiencies (<2%). Deficiencies in any of the protein components of complement are usually caused by a genetic defect that leads to abnormal patterns of complement activation. A deficiency of C2 is associated with recurrent pyogenic infections. It is the most common complement deficiency. It is an autosomal recessive disorder. Half of the patients with homozygous C2 deficiency have no symptoms, but those with symptoms have infections with Streptococcus pneumoniae, Neisseria meningitides, and Haemophilus influenzae. Of symptomatic patients, 50% exhibit a lupus-like disorder with photosensitivity and a rash. A deficiency of C 5 is associated with Leiner's disease. A genetic deficiency of C5 component is associated with increased susceptibility to bacterial infection and is expressed as an autoimmune disorder, e.g. SLE. Patients with dysfunction of C%, Leiner's disease, are predisposed to infections of the skin and bowel, characterized by eczema. The C5 level is normal, but the C5 component fails to promote phagocytosis. A deficiency of C8 is associated with systemic lupus erythematosus. A deficiency makes patients highly susceptible to Neisseria infections.

While serum elevations are NOT generally seen in early stages, which of the following tumor markers are elevated in more advanced stages of breast cancer? - CEA and AFP - AFP and CA 125 - PSA and CA 15-3 - CA 15-3 and CA 549

- CA 15-3 and CA 549 CA 15-3 is also known as CA-breast as it is specifically associated with breast cancer. CA 549 is a glycoprotein found in the serum of breast cancer patients as well. CEA, or carcinoembryonic antigen, is used mainly to monitor the treatment of cancer patients, particularly those with colon cancer. AFP, or alphafetoprotein, is found in elevated levels in primary liver cancer or germ cell tumor. CA 125 is usually used to detect ovarian cancer and also used to monitor therapy. PSA, or prostate specific antigen, is used in the detection of prostate cancer.

The tumor marker associated with ovarian cancer is: - CA15-3/CA27.29 - CA-125 - PSA - CEA

- CA-125 CA-125, a mucin-like glycoprotein, is expressed on the surface of the main body cavity, coelomic, epithelium, and human ovarian carcinoma cells. CA 125 is relatively more sensitive in low-stage ovarian cancer. This classic tumor marker is elevated in cancer, and benign disease of various organs, e.g., pelvic inflammatory disease, endometriosis, but is most useful in the diagnosis and monitoring of ovarian and endometrial carcinomas. CA15-3/CA27.29 both of these tumor markers are associated with breast cancer. CA 15-3 is a marker used to monitor patient response to treatment and recurrence of cancer after mastectomy. A change in the CA 15-3 concentration is more predictive than the absolute concentration. This marker can be positive in other conditions, e.g., liver disease, some inflammatory conditions, and other carcinomas. CA27.29 is called the breast Carcinoma-Associated Antigen. This marker is not recommended for breast cancer screening, but the marker may be helpful in conjunction with other clinical methods for predicting early recurrence of breast cancer. Prostate-Specific Antigen (PSA) has been a controversial marker because of its limitations as a screening tool. PSA is a prostate-tissue-specific marker but not a prostate cancer-specific marker. It is a protease enzyme secreted almost exclusively by prostatic epithelial cells. Blood levels of PSA are increased when normal glandular structure is disrupted by benign or malignant tumor inflammation. False-positive, elevated results have been generated in prostate infection, irritation, benign prostatic hypertrophy, and recent ejaculation. The value of monitoring PSA over time is that an acceleration in the concentration of PSA is suggestive of an increasing tumor volume of prostatic cancer. Carcinoembryonic antigen (CEA) is a tumor marker that is useful in differentiating between benign and malignant pleural and ascites effusions. CEA is found predominantly on normal fetal endocrine tissues in the second trimester of gestation. CEA is clinically useful in monitoring patients after surgery, e.g., colon resection, who had an initially high CEA blood level.

AIDS patients have in increased susceptibility to infection due to a decrease in which of the following? - CD4+ lymphocytes - CD8+ lymphocytes - HIV antibodies - HIV antigens

- CD4+ lymphocytes It is the CD4+ cells are T-lymphocytes that help aid our immune system in attacking foreign antigens that cause infections. The human immunodeficiency virus (HIV) mainly targets the CD4+ cells by using the virus glycoprotein to bind to the lymphocyte receptor. Once the virus is integrated into the cell, it begins to replicate the viral genome. As viral replication progresses, the CD4+ cells decrease, leading to increased susceptibility to infections. CD8+ also helps in the role of immunity by eliminating cancer cells. A decrease in these cells could indicate an autoimmune disease but doesn't indicate an infection by HIV. A decrease in HIV antibodies would not leave the host more susceptible to infection. The antibodies are not the only defense the body has. Antibody levels generally stay stable during infection, but after antiretroviral therapy (ART), the virus decreased as well as the HIV antibody. HIV antigens are part of the virus itself. A decrease in HIV antigens could mean a decrease in viral load.

Which tumor marker is used for colorectal cancer? - CA-125 - AFP - CEA - PSA

- CEA The main clinical use of CEA (carcinoembryonic antigen) is a marker for colorectal cancer and it is frequently elevated in lung, breast, and gastrointestinal tumors.CA-125 (cancer antigen 125) may be useful in detecting ovarian tumors at an early stage and for monitoring treatments without surgical restaging. AFP (a-fetoprotein) is often elevated in patients with hepatocellular carcinoma and germ cell tumors. The best clinical use and the first clinical application of PSA (prostate-specific antigen) testing was to monitor for the progression of prostate cancer after therapy.

Suppose a patient with stiffness in her fingers has a positive antinuclear antibody (ANA) test with a centromere pattern at a 1:1280 titer. What is the most likely diagnosis? - Systemic lupus erythematosus (SLE) - Rheumatoid arthritis - Sjogren's syndrome - CREST syndrome

- CREST syndrome Centromere antibodies are present in over half of patients with the CREST syndrome, an acronym named after the major features of this autoimmune disorder: calcinocis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiesctasia. While the ANA result alone is not diagnostic, this patient is having clinical symptoms of stiff fingers that fits nicely with the centromere ANA pattern. In Systemic lupus erythematosus (SLE), the ANA pattern is usually homogeneous or speckled; in rheumatoid arthitis and Sjogren's syndrome, it is usually specked.

The following characteristics are applicable to Interferon-Gamma Release Assays (IGRAs) except: - Can be used in patients with active tuberculosis disease symptoms - Preferable for patients who have received a bacillus Calmette-Guérin (BCG) vaccination - Can be used instead of purified protein derivative (PPD) - Cannot differentiate latent TB from active tuberculosis infection

- Can be used in patients with active tuberculosis disease symptoms Two currently approved commercially available Interferon-Gamma Release Assays (IGRAs) are approved by the Food and Drug Administration (QuantiFERON® and SPOT TB® test). Interferon-? release assays rely on the fact that T-lymphocytes will release IFN-? when exposed to specific antigens. Depending on which IGRA method is chosen either fresh whole blood or peripheral blood mononuclear cells (PBMCs) are used for testing. White blood cells from most persons that have been infected with M. tuberculosis will release interferon gamma (IFN-?) when mixed with antigens derived from M. tuberculosis. To perform an assay, fresh blood samples are mixed with antigens and controls. M. tuberculosis antigens mixture of synthetic peptides represent ESAT-6, CFP-10 and TB7.7 in QuantiFERON or ESAT-6 and CFP-10 in SPOT TB. The antigens, testing methods, and interpretation criteria for IGRAs differ. However, the IGRA method is not recommended for patients with active tuberculosis symptoms. In addition , an IGRA method should not be used in children younger than 5 years of age. Interferon-Gamma Release Assays (IGRAs) testing is preferable for patients who have received a bacillus Calmette-Guérin (BCG) vaccination (either as a vaccine or for cancer therapy). Prior BCG vaccination does not cause a false-positive IGRA test result. Interferon-Gamma Release Assays (IGRAs) can be used instead of purified protein derivative (PPD) skin test. It is recommended over tuberculosis skin testing in individuals 5 years and older and who have low or moderate risk of disease progression. Interferon-Gamma Release Assays (IGRAs)cannot differentiate latent tuberculosis from active tuberculosis infection.

The purpose of C3a and C5a, the split-products of the complement cascade, is to: - Bind with specific membrane receptors of lymphocytes and cause release of cytotoxic substances. - Cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils. - Bind with membrane receptors of macrophages to facilitate phagocytosis and the removal of debris and foreign substances. - Regulate and degrade membrane cofactor protein after activation by C3 convertase.

- Cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils. The purpose of C3a and C5a, the split-products of the complement cascade, is to cause increased vascular permeability, contraction of smooth muscle, and release of histamine from basophils. C3a and C5a, bioactive fragments of the complement components C3 and C5, respectively play a key role in mediation of immunologically provoked inflammatory responses. C3a and C5a are produced by the activation of the classical pathway and/or the alternative pathway.

Which one of the following statements concerning phagocytosis is FALSE? - Cells are only capable of phagocytizing bacteria. - Membrane "reaches" out and surrounds the material to be internalized. - Once internalized the material is contained in a phagosome. - Only specialized cells are capable of phagocytosis.

- Cells are only capable of phagocytizing bacteria. Phagocytosis is carried out by specialized cells of the innate defense system, mainly the neutrophils, monocytes, macrophages, and dendritic cells. These white blood cells do not only phagocytize bacteria, they can also phagocytize other cells, cellular remnants, and waste products. After contacting the material to be internalized, the phagocytic cell extends its cytoplasmic membrane to surround the material, which becomes engulfed in a vacuole called a phagosome. Lysosomal enzymes from the phagocytic cell are released into the phagosome, and destroy the engulfed material.

What antinuclear antibody (ANA) staining pattern is demonstrated in this microscopic, fluorescent test image? - Homogeneous - Speckled - Nucleolar - Centromere

- Centromere Centromere. This pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells. This is staining of the centromere. There are usually 46 speckles one for each set of chromosomes. Notice the discrete speckling is also seen in the chromosomal area of the metaphase mitotics. Note: (a) points to the nuclei of several interphase cells, the primary consideration for discerning the ANA pattern and (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. The Homogeneous ANA pattern is characterized by smooth staining in the nucleus of the interphase cells. The nucleoli may or may not stain. Notice the smooth staining in the chromosomal area of the metaphase mitotic cells. The Speckled ANA pattern is characterized by granular/speckled staining in the nucleus of the interphase cells and an absence of staining in the chromosomal area of the metaphase mitotic cells. The Nucleolar ANA pattern is characterized by staining in the nucleoli of the interphase cells.

This antinuclear antibody (ANA) test pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells (a) and discrete speckling also in the chromosomal area of the metaphase mitotics (b) when viewed using fluorescent microscopy. This image represents which of the following patterns? - Centromere pattern - Peripheral or rim pattern - Speckled - Multiple nuclear dots

- Centromere pattern This is an example of a centromere ANA pattern. This pattern is characterized by staining of discrete speckles in the nucleus of the interphase cells (a). This is staining of the centromere. There are usually 46 speckles, one for each set of chromosomes. Notice that discrete speckling is also seen in the chromosomal area of the metaphase mitotics (b).In order for the ANA to be positive there must be a clearly discernible pattern in the nucleus of the interphase cells. Metaphase mitotic cells are used to assist in identification of the ANA pattern. Peripheral or rim patterns will display distinct fluorescence around the nucleus membrane. Speckled patterns demonstrate scattered staining within the entire cell nucleus. Multiple nuclear dots are consistent with nucleolar staining.

The initial step in the process of phagocytosis is: - Adherence - Chemotaxis - Engulfment, phagosome formation and fusion - Digestion and destruction

- Chemotaxis Chemotaxis is the initial step in the process of phagocytosis. The primary phagocytic cells are the granulocytic polymorphonuclear neutrophil leukocytes and cells of the mononuclear-macrophage system. Macrophages also participate in antigen presentation and induction of the immune response, as well as secretion of biologically active molecules. The physical occurrence of damage to tissues, either by trauma or microbial invasion, releases substances to initiate migration to the site of injury. Cells are guided to the site of injury by chemoattractants. Neutrophilic granulocytes continually circulate in the blood and can be found at the site of injury in less than 1 hour. Monocytes move more slowly; macrophages are embedded in the tissues or are wandering. Adherence occurs after chemotaxis. Adherence brings the phagocyte into contact with the invading microorganism. Engulfment, phagosome formation and fusion follow adherence. Upon reaching the site of infection, phagocytes engulf the foreign matter and destroy it enzymatically. Digestion and destruction are the final steps in the process of phagocytosis. Digestion is accomplished because granules of the phagocytes contain degradatory enzymes. Unfortunately, the release of digestive enzymes also kills the phagocyte in the process referred to as cytolysis. If invading bacteria are not phagocytized and destroyed, they may establish themselves in secondary sites in the body, producing a secondary inflammation. If bacteria escape from secondary tissue sites, a bacteremia will develop. If a patient is unresponsive to antibiotic therapy, this situation can be fatal.

Which complement pathway and a related initiator can activate complement? - Classic pathway; antigen-IgG antibody complexes - Classic pathway; tumor cells - Alternative pathway; certain viruses and gram-negative bacteria - Mannose-Lectin pathway; apoptotic cells

- Classic pathway; antigen-IgG antibody complexes The classic complement pathway is initiated by the binding of complement protein (C1) complex to antibodies bound to an antigen immune (antigen-IgG antibody)complexes on the surface of a bacterial cell, apoptotic cells, certain viruses and gram-negative bacteria, or C-reactive protein bound to ligand . Although the sequence of events is similar in all three pathways of complement activation, the pathways differ in their pathway initiators and early stages of complement component reactivity . The three pathways do converge at the point of cleavage of C3 to C3b, the central event of the common final pathway, which in turn leads to activation of the lytic complement sequence, C5-C9, and cell destruction. The Classic complement pathway is not initiated by tumor cells. Tumor cells can be can be an initiator associated with the Alternative complement pathway. The Alternative pathway initiators are not restricted to just certain viruses and gram-negative bacteria. Initiators can include various bacteria, fungi, viruses, or tumor cells. The alternative pathway is initiated by contact with a foreign surface, e.g. polysaccharide coating of a microbial cell wall, and the covalent binding of a small amount of C3b in plasma to hydroxyl groups on these cell surface carbohydrates and proteins. The Mannose-Lectin pathway is initiated by microbes with terminal mannose groups not apoptotic cells. Mannose-binding lectin is a pattern recognition molecule of the innate immune system. The binding of mannose-binding lectin to mannose residues terminal mannose groups on a variety of bacteria can initiate complement activation.

Central Tolerance in the human immune defense system operates by: - Clonal deletion of T cells and clonal editing of B cells - Cellular inactivation by weak signaling without a co-stimulus - Clearance of apototic bodies - Antigen segregation

- Clonal deletion of T cells and clonal editing of B cells Central tolerance is characterized by the elimination of immature lymphocytes in primary lymph organs. It is controlled by a mechanism of clonal deletion of T cells and clonal editing of B cells. There are layers of self-tolerance in the human immune system influenced by cellular activity and soluble mediators. The bone marrow and thymus are the sites of action of central tolerance. Central tolerance is initiated during fetal development by the elimination of cells with the potential to react strongly with self-antigens. Cellular inactivation by weak signaling without a co-stimulus describes the mechanism of the layer of the human immune system, peripheral tolerance. Peripheral tolerance is characterized by the elimination of mature lymphocyte clones that occurs in peripheral lymph tissues or clonal anergy. Negative selection is called peripheral tolerance. T cells in the thymus that lack any affinity for self-peptide-self MHC complexes are eliminated in a process called negative selection. B cells undergo negative selection before achieving immunocompetence. Clearance of apoptotic bodies occurs in secondary lymphoid tissue and sites of inflammation. It is characterized by the removal of self-antigen and induction of a negative signal. The layer of tolerance, antigen segregation, takes place in the peripheral organs such as the thyroid and pancreas. The mechanism of action is a physical barrier to self-antigen and induction of a negative signal.

Bruton's agammaglobulinemia is a: - Congenital T-cell disorder - Congenital B-cell disorder - Acquired T-cell disorder - Acquired B-cell disorder

- Congenital B-cell disorder Bruton's agammaglobulinemia is a classic example of an X-linked congenital B-cell disorder. A variant in the gene coding for the enzyme, Bruton tyrosine kinase, leads to the arrest of B-cell development at the pre-B cell stage of cellular development. Consequently, a patient develops repeated susceptibility to infections because of decreased antibody levels for the patient's age. This disorder occurs primarily in young boys. Examples of T-cell immunodeficiences are DiGeorge syndrome, severe cinbubed ummune deficiency, chronic mucocutaneous candidiasis and T-cell activation defects. One of the most well known acquired T-cell disorder is Acquired Immunodeficiency Syndrome (AIDS). The human immunodeficiency virus (HIV) has a marked preference for the CD4+ subset of lymphocytes. As many as 40% of the peripheral blood monocytes, and cells in the lymph nodes, skin and other organs also express measurable amounts of CD4 and can be infected with HIV. Depletion of CD4 lymphocytes and the absolute number of CD4 cells diminishes as AIDS progresses. Multiple conditions can create an acquired B-cell disorder. Autoimmune disorders and Multiple Myeloma are two examples. Other acquired B-cell deficiencies can be related to conditions such as aging and the effect of various medications.

Which branch of the immune system has an immediate response on first exposure to a foreign antigenic stimulus? - Cell Mediated - Specific - Humoral - Innate

- Innate Innate immunity is inherent and nonspecific, meaning that all pathogens are attacked similarly. The skin, mucus in the respiratory tract, and acid pH of the stomach are all examples of the innate defenses that the body has to prevent infection upon first exposure. Cell-mediated and humoral responses are the two main arms of specific, or adaptive immunity. These responses take a longer time than the innate defense to be initiated because it takes time for the T and B lymphocytes to become specifically activated against a foreign antigen.

Thymic hypoplasia is a/an: - Congenital T-cell disorder - Congenital B-cell disorder - Acquired T-cell disorder - Acquired B-cell disorder

- Congenital T-cell disorder Thymic hypoplasia, also known as DiGeorge syndrome or 2211.2 deletion syndrome, is a disorder resulting from a mutation in chromosome 22. This T-cell defect is a congenital anomaly producing faulty embryogenesis of the endodermal derivation of the third and fourth pharyngeal pouches, which results in aplasia of the parathyroid and thymus glands. Bruton's agammaglobulinemia is a classic example of an X-linked congenital B-cell disorder. A variant in the gene coding for the enzyme Bruton tyrosine kinase leads to the arrest of B-cell development at the pre-B cell stage of cellular development. One of the most well-known acquired T-cell disorders is Acquired Immunodeficiency Syndrome (AIDS). The human immunodeficiency virus (HIV) has a marked preference for the CD4+ subset of T-lymphocytes. Multiple conditions can create an acquired B-cell disorder. Autoimmune disorders and Multiple Myeloma are two examples. Other acquired B-cell deficiencies can be related to conditions such as aging and the effect of various medications.

The least immunogenic transplant tissue is: - Kidneys - Bone marrow - Corneas - Lungs

- Corneas Graft rejection of cornea transplants is minimal because of 1. avascularity (the lack of blood vessels) of this tissue; 2. a reasonably low concentration of class I transplant antigens; 3. an essential absence of class II antigens. To prevent rejection, grafts are made as small as possible and placed centrally to avoid contact with the highly vascularized limbic region. Immunosuppressive agents are not routinely administered. In addition to tissue compatibility, which is not perfect unless the kidney is harvested from an identical twin, the harvesting procedure can have a sensitizing effect related to passenger leukocytes against transplantation antigens borne on these cells. HLA-A and HLA-B loci matches have the best chance for the long-term survival of the graft and recipient patient, but increased survival rate with HLA-A and HLA-B matches is determined not as much by class I compatibility as by the HLA-D region-related antigens associated with these regions. Mismatches in human leukocyte (HLA antigens) between the donor and the recipient of bone marrow or hematopoietic stem cells transplant have an increased risk of developing chronic graft-versus-host disease. Lungs are difficult to transplant successfully. Severe rejection is common because of the high density of Ia-positive cells in the vasculature and the high concentration of passenger leukocytes trapped in the alveoli and blood vessels. Intensive immunosuppressive therapy is needed to maintain the graft.

Which laboratory assay is a highly specific indicator and the most sensitive assay for a diagnosis of rheumatoid arthritis? - Cyclic citrullinated peptide - Sensitized sheep cells - Latex particle agglutination - C-Reactive Protein agglutination

- Cyclic citrullinated peptide Cyclic citrullinated peptide antibodies are highly specific indicators for rheumatoid arthritis. Antibodies to CCPs (anti-CCP) were first described in 1998. After the introduction of commercial ELISA products using the so-called second generation peptides, there has been increased interest in using this marker in the diagnosis. Anti-CCP antibodies are detectable in about 69-83% of patients with RA and have specificities ranging from 93% to 95%. Compared with other assays for antibodies in RA, CCP is considered to be more sensitive. Antibodies can be detected up to 16 years before the first clinical symptoms of RA appear. Agglutination tests for RF using a sensitized sheep cell test generally detect IgM rheumatoid factors (RFs). IgM RF is manifested in approximately 70% of adults but is not specific for RA. RF has been associated with some bacterial and viral infections, and some chronic infections, and cancer. Elevated values may be observed in the normal older adult population. Agglutination tests for RF using latex agglutination generally detect IgM RFs. Although a latex agglutination procedure has a 95% correlation with a clinical diagnosis of probable or definite rheumatoid arthritis, rheumatoid factor (RF) is not exclusively limited to patients with rheumatoid arthritis. In using latex tests for the detection of RF, a positive result can be expected in less than 5% of healthy individuals. In patients 60 years old and older, as many as 30% may be seropositive. C-Reactive Protein (C-RP) is a rapidly synthesized, acute phase reactant. It is an indicator of acute inflammation. Traditionally, C-RP has been used clinically for monitoring infection, autoimmune disorders, and, more recently, healing after myocardial infarction. The C-RP rapid latex agglutination test is based on the reaction between patient serum containing C-RP as the antigen and the corresponding antihuman (C-RP) coated to the surface of latex particles. The latex particles allow for easy visual detection of an antigen-antibody reaction. The clinical applications of C-RP are evaluation, including detecting inflammatory disease, particularly infections, screening for inflammatory and malignant disease, and monitoring therapy in inflammatory disease.

The most highly specific indicator for rheumatoid arthritis is: - Rheumatoid factor - Cyclic citrullinated peptide antibodies (CCP antibodies) - Immune complexes - Complement

- Cyclic citrullinated peptide antibodies (CCP antibodies) CCP antibodies are a highly specific indicator for RA. Antibodies to CCP-1 (anti-CCP-1) were first described in 1998, followed by the introduction of commercial ELISA methods using the second-generation peptides (CCP-2). Anti-CCP IgG antibodies are present in about 69% to 83% of patients with RA and have specificities ranging from 93% to 95%. Compared to other assay methods for RF, CCP is considered to be more sensitive (specificity >95%). Citrullinated tenascin-C (cTNC) is a newer glycoprotein with a 98% accuracy rate for ruling out RA. Agglutination tests for RF generally detects IgM RFs. Latex agglutination is sensitive but can produce a fairly high number of false-positive results. Because conventional procedures are semi-quantitative, they may be insensitive to changes in titer and may detect only those RFs that agglutinate. Soluble circulating immune complexes and cryoprecipitable proteins consisting of immunoglobulins, complement components, and RFs are demonstrable in the sera of some patients with RA. Complement levels are generally normal in patients with rheumatoid arthritis, except for patients with vasculitis.

Which of the following microscopic techniques is best suited for direct examination of the infectious agent of syphilis? - Light microscopy - Phase-contrast microscopy - Dark-field microscopy - Electron microscopy

- Dark-field microscopy Syphilis is caused by Treponema pallidum, which is a spirochete and cannot be cultured outside the body.The best way to identify T. pallidum directly from the specimen is to use dark-field microscopy. Dark-field microscopy allows a lower limit of resolution than bright-field microscopy, which helps the tiny spirochetes to be seen in patient samples. In dark-field microscopy, there is a dark background where directly transmitted light is excluded by a dark-field condenser allowing only scattered light to be focused on the specimen. With dark-field microscopy, bacteria appear luminous against a dark background.Light microscopy is the most common method used in microbiology to view organisms that are stained, most commonly via gram stain. Light is transmitted through the specimen to see the shape and color of the cells.Phase-contrast microscopy is typically used to view live organisms or unstained cells. Electron microscopy (scanning or transmission) is typically used for viruses.

The positive predictive value of a Borrelia burgdorferi (B. burgdorferi) antibody assay depends on the likelihood of ____________ being present. - Zika virus - Lyme disease - Human ehrlichiosis - Babesiois

- Lyme disease Lyme disease (Lyme borreliosis) is caused by a spirochete bacterium, Borrelia burgdorferi. Cellular immune responses to B. burgdorferi antigens begin in the early stage of clinical illness, and a humoral (antibody) immune response follows. Serology tests are insensitive during the first several weeks of infection. In the United States, only about 20% to 30% of Lyme disease patients have early positive antibody responses, usually IgM, but 2 to 4 weeks later, about 70% to 80% demonstrate IgM antibodies even after antibiotic treatment. After about 1 month, most patients with an active infection have IgG antibody responses. After antibiotic treatment, antibody titers slowly fall, but IgG and even IgM responses may persist for many years after treatment. An IgM response cannot be interpreted as a manifestation of a recent infection or reinfection unless the appropriate clinical characteristics are present. Specific IgM or IgG antibodies against B. burgdorferi are usually not detectable in a patient's serum unless symptoms have been present for at least 2 to 4 weeks. Assays for the detection of antibodies to B. burgdorferi are the most practical means for confirming infection. The Centers for Disease Control and Prevention (CDC) currently recommends a two-step process when testing blood for evidence of antibodies against the Lyme disease bacteria. The first step uses EIA or rarely IFA. If the first step is negative, no further testing of the specimen is recommended. If the first step is positive or indeterminate, the second step should be performed. The second step uses an immunoblotting procedure, usually a Western Blot (WB) test. Results are considered positive only if the EIA or IFA and the immunoblot test results are both positive. The CDC does not recommend skipping the first test and doing only the WB test because this will increase the frequency of false-positive results. Zika virus is a recently emerging vector-borne disease in the United States. Diagnosis of Zika is based on a person's recent travel history, symptoms, and laboratory test results. The Centers for Disease Control and Prevention (CDC) has developed protocols for testing blood or urine to confirm a Zika infection. Trioplex Real-Time RT-PCR (rRT-PCR) assay and the Zika IgM-antibody capture (MAC)-ELISA assay is distributed to qualified public health laboratories. Human ehrlichiosis was first described in the United States in 1986. It is a tickborne rickettsieae of the genus, Ehrlichia. A definitive diagnosis is based on the inclusion of Ehrlichia in an infected leukocyte. Detection of IgM and IgG antibodies are confirmatory results. Since January of 2011, cases of babesiosis have been reported to the CDC. Babesia is a rare and sometimes fatal tickborne, parasitic disease that infects red blood cells. In symptomatic patients, babesiosis usually is diagnosed by microscopic examination of a stained blood smear. Acute and convalescent antibody titer may be useful for diagnosis. Only IgG antibody determinations are performed. PCR amplification can be used for diagnosis.

Direct examination of treponemes can be performed by: - Light microscopy examination - Darkfield microscopy examination - VDRL testing - Rapid Plasmin Reagin (RPR) testing

- Darkfield microscopy examination Darkfield microscopy allows for direct observation of spirochetes from an active syphilitic lesion. It is the test of choice for examining symptomatic patients with primary syphilis. A darkfield examination is also suggested for immediate results in cases of secondary syphilis. The traditional logarithm for syphilis testing of suspected patients with syphilis begins with observations of classic lesions present, suggestive sexually transmitted infection history, and current sexually transmitted disease. Non-treponemal testing such as the Rapid Plasmin Reagin (RPR) is the next step. A reverse sequence testing algorithm begins with the same patient observations but the next step is to perform treponemal testing by chemiluminescence immunoassay or enzyme immunoassay. Light microscopy examination is not effective in the detection of spirochetes. Darkfield or fluorescent microscopy techniques are required for direct observation of spirochetes. The VDRL assay is a flocculation test that measures IgM and IgG antibodies to lipoidal material released from damaged host cells, to lipoprotein-like material, and possibly to cardiolipin released from the treponemes. Without some other evidence for the diagnosis of syphilis, a reactive nontreponemal test does not confirm T. pallidum, infection. Antilipoidal antibodies are antibodies that are not only produced as a consequence of syphilis and other treponemal diseases but also may be produced in response to nontreponemal diseases of an acute or chronic nature in which tissue damage occurs. Rapid Plasmin Reagin (RPR) testing is a non-treponemal testing method. Traditionally, it is the next step in serological assessment. The RPR is the most widely used assay to determine the presence of reagin, an antibody formed against cardiolipin, a lipid remnant of damaged cells, cholesterol, and lecithin, is used to detect the nontreponemal regain antibodies.

Cytomegalovirus (CMV) appears to suppress cell-mediated immune functions. Which of the following is a characteristic finding in persons infected with CMV? - Increased CD4+ cells; decreased CD8+ cells - Increased CD4+ cells; increased CD8+ cells - Decreased CD4+ cells; increased CD8+ cells - Decreased CD4+ cells; decreased CD8+ cells

- Decreased CD4+ cells; increased CD8+ cells The correct answer is 'decreased CD4+ cells; increased CD8+ cells'. Cytomegalovirus infects neutrophils, which transport the virus to other areas of the body. The virus is known to suppress cell-mediated immunity and cause the production of autoantibodies that are cytotoxic toward lymphocytes.CD4+ cells represent T helper lymphocytes, while CD8+ cells represent T suppressor lymphocytes. Thus, what is commonly seen in CMV infections are a decrease in T helper cells and an increase in T suppressor cells.

All of the following are uses of nucleic acid tests for HIV infection, EXCEPT? - Monitor the effectiveness of antiretroviral therapy - Obtain a baseline value prior to the start of antiretroviral therapy - Diagnose HIV infection - Determine the degree of immune suppression caused by HIV

- Determine the degree of immune suppression caused by HIV Qualitative nucleic acid tests for HIV are used to screen for the infection or make an initial patient diagnosis. Quantitative nucleic acid tests, otherwise known as viral load tests, indicate the amount of HIV circulating in the plasma. These tests are used to obtain a baseline value prior to the start of antiretroviral therapy and to monitor patients undergoing treatment with antiretroviral drugs to determine if the therapy is effective or if a change in therapy is needed. The degree of immune suppression caused by HIV is evaluated by measuring the number of CD4 T cells in the peripheral blood, as these cells are destroyed by the virus.

A nasopharyngeal specimen is processed and fixed onto a microscope slide. Next, fluorescein-conjugated antibody is added to the slide. The specimen is incubated with the labeled antibody, washed, and then observed for fluorescence. Which of the following techniques best describes this process? - Enzyme-linked immunosorbent assay (ELISA) - Latex agglutination - Indirect immunofluorescence - Direct immunofluorescence

- Direct immunofluorescence In direct immunofluorescence or direct fluorescent antibody test (DFA) tests can be used to detect antigens of Legionella, Bordetella, Neisseria, and Treponema in appropriate clinical specimens. The specimen is fixed to a microscopic slide and fluorescein-conjugated antibody is added to the slide and incubated. If the corresponding antigens are present in the specimen, they will bind to the fluorescent antibody. DFA can detect only antigens, not antibodies. The method described is a DFA technique. In ELISA, antibody or antigen is bound to an enzyme that can catalyze a reaction. The antibody-binding site remains free to react with the antigen; a colored end-product is measured spectrophotometrically. ELISA can be used to detect antigen or antibody, depending on the method. In latex agglutination, latex is used as a carrier for specific antibodies. If antigen is present in the patient specimen, it will combine with the binding site of the antibody, which is bound to the latex particles and agglutination occurs. In indirect immunofluorescence, or indirect fluorescent antibody (IFA) techniques, antibody or antigen can be detected. To detect antigen, the specimen is fixed onto a microscope slide and then an excess of unlabeled antibody directed against the organism to be detected is added to the slide and permitted to react with the antigen. Unbound antibody is removed by washing and then a second antibody, such as a fluorescein-labeled immunoglobin is added to the complex. After a second wash, the slide is read for fluorescence. IFA can be used to detect antibody present in a specimen by reacting with antigens that are fixed onto a microscopic slide, incubating, washing, and adding a second fluorescein-labeled antibody.

When are data collected in a real-time PCR procedure? - Prior to the addition of fluorescent dyes or probes - At a single endpoint - During nucleic acid amplification - During the cooling stage

- During nucleic acid amplification In real-time PCR, a fluorescent dye is added during the amplification stage allowing continuous measuring and monitoring in real-time. The fluorescent dye or probe is what allows us to collect data in real-time. Real-time PCR allows for continuous monitoring. The cooling state is in preparation for sample storage.

Which of the following serological tests would be used for the diagnosis of Q-fever? - Weil-Felix test - Quellung test - EIA or indirect immunoflourescence - Cold agglutinin test

- EIA or indirect immunoflourescence Serology testing utilizing indirect immunofluorescences or EIA is the most commonly used methodology. IFA is considered the reference method due to its high specificity and sensitivity in both acute and chronic infections. It is also reliable, cost-effective, and easy to perform. The Weil-Felix test detects cross-reacting rickettsia antibodies by using Proteus vulgaris. The Quellung test utilizes antibodies to bind to the bacterial capsule, which can be used to identify serotypes of Streptococcus pneumoniae. Cold agglutinins are autoantibodies that cross-react with red blood cells (RBCs). They cause RBCs to clump together when the person is exposed to cold temperatures and increases the chances of those RBCs getting destroyed.

For the diagnosis of Systemic Lupus Erythematosus (SLE) which of the following test principles provides the highest specificity? - FANA - ELISA - Latex ANA - CRP

- ELISA ELISA tests are available allowing us to determine the presence of anti-Smith, anti-double-stranded DNA, anti-histone, anti-SS-A, anti-SS-B, anti-Rnp or anti-Scl-70 which provide greater specificity for a diagnosis of SLE. Fluorescence anti-nuclear antibody techniques, while sensitive are less specific for differentiating SLE from other autoimmune diseases. Latex ANA are screening tests for anti-nuclear antibodies that would be followed by more specific FANA or ELISA testing. CRP is a screening tests for an increase in acute phase proteins that are non-specific.

Which of the following cells are capable of producing antibodies? - Thrombocytes - Macrophages - Lymphocytes - Neutrophils

- Lymphocytes B lymphocytes are responsible for humoral immunity. B lymphocytes are activated and differentiate to a plasma cell. Antibodies are then made towards the antigen initiating this response. Thrombocytes are integral in primary hemostasis, while macrophages and neutrophils phagocytize and degrade foreign pathogens.

A traveler is being evaluated at a local hospital for gastrointestinal pain, fever, and diarrhea. The patient has recently returned from a month-long visit to Southeast Asia. The patient has no recent history of sexual activity or IV drug use but did describe conditions of poor sanitation where they were visiting. If liver function test results were elevated and bilirubinuria was noted, which of the following would be the next logical test to order? - ELISA test for the Hepatitis B Surface Antigen (HBsAg) - Recombinant Immunoblot Assay (RIBA) test for Hepatitis C - Western Blot test for HIV - ELISA testing for Hepatitis A antigens in the stool

- ELISA testing for Hepatitis A antigens in the stool ELISA testing for Hepatitis A antigens in the stool. Hepatitis B, C, and HIV are spread primarily through sexual contact or IV drug use and needle sharing. While it is possible to contract these viruses through other means, the patient history of visiting areas of low sanitation in Asia is more indicative of an enterically (fecal-oral) transmitted organism like Hepatitis A. The earliest detectable marker for Hepatitis A is the presence of viral antigens in the stool, which are most often tested for using ELISA methodology. Hepatitis B Surface Antigen would be tested for in the case of suspected Serum Hepatitis or Hepatitis B. This is a bloodborne pathogen, and based on the patient's history and clinical signs and symptoms would not be the most likely cause. Like Hepatitis B, Hepatitis C is a bloodborne pathogen and would not be the most likely cause of this patient's signs and symptoms. Like Hepatitis B, HIV is a bloodborne pathogen and would not be the most likely cause of this patient's signs and symptoms.

Corneal tissue transplantation has an extremely high success rate for a variety of reasons, including all of the following with the exception of: - Avascularity - Reasonably low concentration of class I antigens - An essential absence of class II antigens - Eccentrically place grafts

- Eccentrically place grafts Eccentrically placed grafts of the cornea are subject to a high rate of immunologic failure because vascularity will allow for contact with lymphocytes that can facilitate the rejection of a transplant. To prevent rejection, corneal transplants are made as small as possible, and the transplant is placed centrally to avoid contact with the highly vascularized limbic regions. The cornea is avascular. Subsequently, no HLA matching is performed for corneal tissue transplants. Class I transplantation antigens are present in the cornea in a low concentration. Class II transplantation antigens are essentially absent in the cornea.

When a polyclonal gammopathy is compared to a monoclonal gammopathy, a patient with a polyclonal gammopathy has: - A single class and type of immunoglobulin. - Elevated levels of several classes of immunoglobulin molecules. - Bence Jones protein in the urine - M spike on serum protein electrophoresis

- Elevated levels of several classes of immunoglobulin molecules. Elevated levels of several classes of immunoglobulin molecules defines a polyclonal gammopathy. In this condition, an increase in more than one immunoglobulin occurs that involves several clones of plasma cells. A single class and type of immunoglobulin defines a monoclonal gammopathy. Bence Jones protein in the urine is a characteristic of Multiple myeloma, a monoclonal gammopathy. An M spike on serum protein electrophoresis is a demonstration of homogeneous M component composed of monoclonal IgM.

Which one of the following statements about endocytosis is incorrect? - Phagocytosis is a form of endocytosis. - In endocytosis, the cell membrane invaginates and isolates a foreign particle in a vesicle. - Endocytosis is a mechanism for viruses to enter cells. - Endocytosis is the process by which phagosomes expel the macromolecules inside.

- Endocytosis is the process by which phagosomes expel the macromolecules inside. Endocytosis is the reverse process of exocytosis. Exocytosis is a process of expelling a foreign material. Phagocytosis is a form of endocytosis. This important body defense mechanism is a process where specialized cells engulf and destroy foreign particles, such as microorganisms or damaged cells. Macrophages and segmented neutrophils are the most important phagocytic cells. In endocytosis, the cell membrane invaginates and forms vesicles to isolate foreign particles. Endocytosis is a mechanism for viruses to enter cells.

What condition would be suspected in an asymptomatic patient with greater than 20% atypical (reactive) lymphocytes on their peripheral blood smear? - Herpes simplex virus infection - Epstein-Barr virus infection - Bacterial meningitis - Acute leukemia

- Epstein-Barr virus infection Epstein-Barr virus causes infectious mononucleosis, which is associated with atypical (reactive) lymphocytosis. The peripheral blood smear may show 5%to 30% atypical lymphocytes. Patients are often asymptomatic, however, they can present with fatigue, malaise, fever, sore throat and cervical lymphadenopathy. Herpes simplex virus infection does produce atypical lymphocytosis, however, the percentage of atypical lymphocytes will be less than 20%. Bacterial meningitis would present as an increase in neutrophils, which help fight bacterial infections. Acute leukemias generally present with many immature cells in the bone marrow and/or the peripheral blood. The types of immature cells present will depend upon the cell like affected, myelogenous, monocytic or lymphocytic.

All of the following are indicators of sepsis, EXCEPT? - Erythrocytosis - Increased heart rate - Leukocytosis - Increased body temperature

- Erythrocytosis Sepsis results in an immune response by the body. This response includes increasing body temperature and leukocytes in order to help fight off the infection and increased heart rate in order to get more blood and oxygen to the tissues. Erythrocytosis is not part of the immune response.

Which of the following is a confirmatory test for syphilis? - RPR - FTA-ABS - VDRL - Automated Reagin Test (ART)

- FTA-ABS FTA-ABS is the correct answer. FTA-ABS (Fluorescent Treponema pallidum absorption test) is not intended for use as a screening test. It should only be used to differentiate between true positives, false positives, and in late or latent syphilis. RPR is incorrect. RPR (Rapid Plasma Reagin) is a screening test for syphilis and is known to have a high rate of false-positive reactions. The RPR test is a nontreponemal test that can produce positive reactions not only with syphilis but with leprosy, tuberculosis, chancroid, leptospirosis, malaria, and autoimmune diseases. VDRL is incorrect. VDRL (Venereal Disease Research Laboratory) is a screening test for syphilis and is known to have a high rate of false-positive reactions. The VDRL test is a nontreponemal test that can produce positive reactions not only with syphilis but with leprosy, tuberculosis, chancroid, leptospirosis, malaria, and autoimmune diseases. Automated Reagin Test (ART) is incorrect. This test is an automated nontreponemal test that is used in the screening for syphilis. People with syphilis, as well as those with other infectious diseases, produce reagin antibodies (nontreponemal antibodies)that are detected by the RPR, VDRL, and ART tests.

Concerning antigen-antibody reactions, the prozone effect causes which of the following results? - False positive - False negative - No reaction at all - Mixed field reaction

- False negative Both antibody excess (prozone) and antigen excess (postzone) result in the formation of small antigen-antibody complexes. This results in false negative reactions because the number of agglutinated cells are decreased. False positive reactions may be caused by overcentrifugation, for example, which can cause red cells to adhere too strongly to the test tube and be difficult to shake loose. While prozone results in a false negative reaction, antigen-antibody reactions do still occur - they are just too small to see with the naked eye. Mixed field reactions are most commonly caused by a dual cell population which may occur if a patient has been recently transfused.

The properties of an antibody class are defined by the: - Size of the immune complex - Nature of the stimulating antigen - Fab end of the molecule - Fc end of the molecule

- Fc end of the molecule The portion of antibodies where the C terminal region of each glycoprotein chain is located is called the Fc portion. The Fc portion has a constant amino acid sequence that defines the class and subclass of each antibody. The Fc portion is responsible for the biological activity of the antibody. Depending on the class of antibody, some of the functional activities of the Fc portion of antibodies include activating the complement pathway and binding to natural killer cells. An immune complex is a noncovalent combination of an antigen with its specific antibody. An immune complex can be small and soluble or large and precipitating, depending on the nature and proportion of the antigen and antibody. It does not influence the properties of an antibody class. The effective function of an antigen depends on foreignness, molecular weight, structural stability, and complexity. None of these characteristics influence the properties of an antibody class. The Fab section of an immunoglobulin molecule has antigen combining sites that influence reactivity. The Fab does not influence the properties of an antibody class.

During which stage of a syphilis infection will a patient develop the painless chancre? - First stage - Second stage - Latent stage - Third stage

- First stage The chancre will develop during the primary stage of a syphilis infection. During this stage the patient is highly contagious.The secondary stage of syphilis infection is characterized by the development of a rash all over the body including the palms of the hands and soles of the feet. Again, the patient is highly contagious during this phase.The latent phase does not present symptoms and the patient is not usually contagious, except pregnant mothers to their fetuses.The tertiary phase is considered the most destructive phase of the infection, characterized by large sores, gummas, cardiovascular syphilis, or neurosyphilis.

In what trimester is there the greatest risk for the manifestation of complications in maternal rubella infection? - First trimester - Second trimester - Third trimester - Delivery

- First trimester The CDC reports that the highest risk of congenital infection of rubella is highest during the first 12 weeks of gestation. Defects are rare after infection in the 20th week of gestation or later.

VDRL and RPR are examples of which of the following types of test methodologies? - ELISA - Immunofluorescence - Flocculation - Hemagglutination

- Flocculation Flocculation tests are antigen-antibody tests in which the final product is a precipitin whose visible clumps can be seen either microscopically (VDRL) or macroscopically (RPR). Both VDRL and RPR are serologic screening tests for syphilis. ELISA is an enzyme-linked immunosorbent assay in which an antibody that contains an enzyme gives a visually discerning end product as the enzyme catalyzes a given reaction. Immunofluorescence testing uses immobilized antigens from the test sample and mono- or polyclonal antibodies that bind and fluoresce if antigens are present. Hemagglutination is the clumping of red blood cells.

What is the process of monoclonal antibody production? - Stimulation of activated T cells - Fusion of plasma cell secretions - Fusion of antibody specific lymphocyte and myeloma cell - Multiplication of cytotoxic T cells

- Fusion of antibody specific lymphocyte and myeloma cell Monoclonal antibodies (MAbs) are monospecific antibodies that are the same because they result from one type of immune cell. All clones of a unique parent cell, a hybrid cell line, usually arise from a hybridoma. The fusion of a specific antibody-producing lymphocyte with a myeloma cell will multiply to become a source of pure monoclonal antibody. Modern methods for this process of producing MAbs are a refinement of the original Kohler, Milstein, and Jerne process. Activated T cells produce the cytokines: IL-2, IL-3, and IL-22. Activated T cells are not associated with monoclonal antibody production. Plasma cells have the function of synthesis and excretion of immunoglobulins. These are not monoclonal antibodies. Antibodies secreted by plasma cells consist of four chains-two light chains, and two heavy chains. They can be enzymatically cleaved into Fab and Fc fragments. The Fc fragment contains the markers that distinguish the different class of antibody and sites that will bind and activate complement and bind to Fc receptors on cells. Cytotoxic T cells (CD8+) undergo a change in the expression of costimulatory molecules on their surface. Cytolytic effector molecules, perform, and granzyme A-B is the actual functional molecules for killing target cells. Cytotoxic T cells (CD8+) are not associated with monoclonal antibody production.

Diseases associated with a dysfunction of polymorphonuclear neutrophils (PMNs) include all of the following with the exception of: - Chediak-Higashi syndrome (CH) - Chronic granulomatous diseases (CGDs) - Gaucher 's Disease - Myeloperoxidase deficiency (MPO)

- Gaucher 's Disease Gaucher's disease is a monocyte-macrophage disorder caused by a rare genetic defect. There is a high incidence of this disease in Ashkenazi Jews. There are two types of the disease: neuronopathic and nonneuronopathic, depending on symptoms. The disorder represents a deficiency of B-glucocerebrosidase, the enzyme that normally splits glucose from its parent sphingolipid, glucosylceramide. As a result of this enzyme deficiency, cerebroside accumulates in histiocytes (macrophages). Gaucher cells, typically a large cell with one to three eccentric nuclei and a characteristically wrinkled cytoplasm, are found in the bone marrow, spleen, and other organs of the mononuclear phagocyte system. Gaucher cells are rarely seen in the circulating blood. Chediak-Higashi syndrome is a congenital neutrophil abnormality. Because of an abnormal granulation of neutrophils, it results in a qualitative neutrophil disorder of neutrophils. The neutrophils with giant granules display impaired chemotaxis and delayed killing of ingested bacteria. Chronic granulomatous diseases(CGDs) are congenital neutrophil abnormalities. They are a genetically heterogeneous group of disorders of oxidative metabolism affecting the cascade of events required for H2O2 production by phagocytes during phagocytosis. Life-threatening infections can result. Patients with autosomal-recessive form may have a less severe clinical course than patients with X-linked forms of CGD Myeloperoxidase deficiency is a congenital neutrophil abnormality. Myeloperoxidase is an iron-containing heme protein responsible for the peroxidase activity characteristic of azurophilic granules in neutrophils. Human neutrophils contain many granules of various sizes that are morphologically, biochemically, and functionally distinct. The azurophilic granules normally contain myeloperoxidase. In myeloperoxidase deficiency, the azurophilic granules are present, but myeloperoxidase is decreased or absent. If phagocytes are deficient in myeloperoxidase, the patient's phagocytes manifest a mild-to-moderate defect in bacterial killing and a marked defect in fungal killing in vitro.

The infectious disease process in which large numbers of activated macrophages and histiocytes are collected at the site of inflammation is called? - Purulent - Granulomatous - Chronic - Opportunistic

- Granulomatous The correct answer is granulomatous. If many activated macrophages and histiocytes aggregate in the area, particularly with the formation of multinucleated giant cells, the reaction is called granulomatous. The sequence of an inflammatory reaction begins with the local accumulation of segmented neutrophils, a stage that is called purulent or suppurative. If the infective agent is not removed by the neutrophils, mononuclear inflammatory cells, initially lymphocytes, followed by monocytes and macrophages invade the area, leading to chronic infection. Plasma cells often become an integral component of the chronic inflammatory reaction when antibody formation is at its peak. Opportunistic infection is a term used to describe the evolution of an infectious disease in an immunocompromised or debilitated host by a bacterial species that does not commonly cause infection in a healthy host.

What sero-marker is the first marker to become positive in Hepatitis B and is associated with the infective stage? - HBc antibody - Hbe antigen - HBs antigen - Hbs antibody

- HBs antigen Hepatitis B surface antigen, or HBs, is a protein that is part of the lipoprotein envelope of the virus. The protein will be present via laboratory testing in the blood HBV infections, rising early and reducing to non detectable levels 4-6 months after recovery unless patient develops chronic hepatitis. The hepatitis B core antibody rises after a recent infection and will be positive just after the HBsAg disappears. The hepatitis Be antigen is found in between the nucleocapsid and lipoprotein envelope of the virus. Positivity with serology tests indicates infectivity of the patient. The hepatitis B surface antibody is part of the immune response to the hepatitis B surface antigen (IgM rising first, then IgM) and can result in long term immunity.

Which is the first marker (antigen or antibody) which will become positive after exposure to Hepatitis B? - HBsAg - Anti-HBs - Anti-HBe - IgG anti-HBc

- HBsAg HBsAg is detectable 2 to 12 weeks post-exposure during the acute stage and becomes undetectable in 12 to 20 weeks after the development of anti-HBsAg. HBeAg appears after the HBsAg and, in recovering patients, disappears before HBsAg. IgM anti-HBc is the first antibody to appear, and it persists for about 6 months.

What is the expected serological response in an immunocompetent patient who has been vaccinated for hepatitis B? - HBsAg (neg), Anti-HBc(neg), anti-HBs (pos) - HBsAg (pos), Anti-HBc(pos), anti-HBs (neg) - HBsAg (neg), Anti-HBc(pos), anti-HBs (pos) - HBsAg (neg), Anti-HBc(pos), anti-HBs (pos)

- HBsAg (neg), Anti-HBc(neg), anti-HBs (pos) HBsAg (neg), Anti-HBc(neg,) anti-HBs (pos) are the expected serological responses demonstrated after an HBV vaccination series. There is no evidence of HBsAg , Hepatitis B surface antigen nor anti-HBs. The presence of antibody to Hepatitis B surface antigen (anti-HBs) is the expected response to being immunized to HBV and the patient is considered to not be susceptible to hepatitis B infection. HBsAg (pos), Anti-HBc(pos,) anti-HBs (neg) is the likely profile of a patient with chronic hepatitis B. HBsAg (neg), Anti-HBc(pos) anti-HBs (pos) is the profile of a patient who has recovered from an HBV infection. HBsAg (neg), Anti-HBc(pos) anti-HBs (pos) is the profile of a patient who is immune to HBV because of natural infection.

What three hepatitis B virus (HBV) early markers are detectable in serum during the first two months after infection? - HBsAg, HBeAg, anti-HBc - HBeAg, Anti-HBe, anti-HBs - Anti-HBc, anti-HBs, anti-HBe - HBsAg, AntiHBs, anti-HBe

- HBsAg, HBeAg, anti-HBc HBsAg, HBeAg, anti-HBc are the three, earliest detectable serological markers of importance in hepatitis B virus infection. Hepatitis B is a complex DNA virus. HbsAg is the envelope protein; HBeAg is a soluble nucleocapsid protein. The initial detectable marker found in serum during the incubation of hepatitis B infection is HBsAg. HBsAg usually becomes detectable 2 weeks to 2 months before clinical symptoms and as soon as 2 week after infection. This marker is usually present for 2 to 3 months duration. HBeAg, is found in the serum of some HBsAg-positive patients. HBV DNA and DNA polymerase will appear along with HBeAg. These are all indicative of active viral replication. HBeAg is rarely found in the absence of active viral replication. Hepatitis B core antibody, anti-HBc, is the antibody to core antigen. Anti-HBc is found 2 - 4 weeks after the appearance of the surface antigen, at around the same time as the development of the signs and symptoms. In acute infections, clearance of the virus is marked by the disappearance of HBeAg and the appearance of anti-HBe. Anti-Hbc may be the only serologic marker during the time between the disappearance of detectable HBsAg and the appearance of detectable antibody to HBsAg (anti-HBs). This period of time that can last for a few weeks, several months, or 1 year, is called the anticore window or hidden antigen phase of HBV infection. Incorrect answer choice -HBeAg, Anti-HBe, anti-HBs HBeAg is one of the earliest detectable serological markers of importance in hepatitis B virus infection. However, Anti-HBe and anti-HBs develop after the initial phase of infection, during convalescence and recovery from HBV infection. Development of anti-HBe is the first serologic evidence of the convalescent phase and usually appears shortly after clearance of HBeAg. HBV exists in a carrier state and carriers commonly have anti-HBe in their serum. Anti-HBs is a serologic marker of recovery and immunity. Incorrect answer choice-Anti-HBc, anti-HBs, anti-HBe Anti-HBc is an indicator of a early hepatitis B virus (HBV) infection. However, anti-HBs and anti-HBe are not early indicators. Anti-HBs and anti-HBe develop later during convalescence and recovery from HBV infection. Anti-HBs is a serologic marker of recovery and immunity. Anti-HBs is probably the major protective antibody in this disease. Thus hepatitis B immune globulin is so named because it contains high levels of anti-HBs. Development of anti-HBe is the first serologic evidence of the convalescent phases. development of anti-HBe is the first serologic evidence of the convalescent phase and usually appears shortly after clearance of HBeAg. Incorrect answer choice -HBsAg, AntiHBs, anti-HBe HBsAg is an initial detectable marker found in serum during the incubation of hepatitis B infection. HBsAg usually becomes detectable as soon as 2 week after infection. However, anti-HBs and anti-HBe are not among the three early serologic markers in HBV infection. Anti-HBs does not arise during the acute disease but it is manifested during convalescence as a serologic marker of recovery and immunity. Development of anti-HBe is the first serologic evidence of the convalescent phases.

A kidney graft would have the BEST chance of survival post-transplantation if it were: - HLA non-identical, mixed lymphocyte culture (+), ABO identical. - HLA identical, mixed lymphocyte culture (+), ABO identical. - HLA identical, mixed lymphocyte culture (-), ABO identical. - HLA identical, mixed lymphocyte culture (-), ABO non-identical.

- HLA identical, mixed lymphocyte culture (-), ABO identical. A graft which is matched based on HLA and ABO typing is ideal. The mixed lymphocyte culture, or MLC, should be negative also to prevent graft vs. host disease in transplant procedures. A non-identical HLA is likely to result in rejection. A positive mixed lymphocyte culture indicates lymphocyte activation which can contribute to rejection of tissue. An ABO match is essential to reduce the chance of organ rejection.

Identify the antinuclear antibody (ANA) staining pattern in the image (a) and interpret what related disorder can be associated with this pattern? - Homogeneous or Diffused staining pattern; Systemic Lupus Erythematosus - Homogeneous or Diffused staining pattern; Scleroderma - Nucleolar staining pattern; Sjogren's syndrome - Peripheral or rim staining pattern; active Systemic Lupus Erythematosus

- Homogeneous or Diffused staining pattern; Systemic Lupus Erythematosus The image displays a homogeneous ANA staining pattern. This pattern is characterized by smooth staining in the nucleus of the interphase cells. The nucleoli may or may not stain. Notice the smooth staining in the chromosomal area of the metaphase mitotic cells (b). Note: In order for the ANA test to be positive, there must be a clearly discernible pattern in the nucleus of the interphase cells. Metaphase mitotic cells are used to assist in the identification of the ANA pattern. (a) points to the nucleus (nuclei) of the interphase cell(s), the primary consideration for discerning the ANA pattern, and (b) indicates the metaphase mitotic cells. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in the identification of the ANA pattern. Disorders related to a homogeneous ANA staining pattern include Systemic Lupus Erythematosus (SLE), Rheumatoid arthritis, Sjogren's syndrome, or Mixed Connective tissue Disease. The image displays a homogeneous or diffused ANA staining pattern. Although the presented ANA staining pattern displays a homogeneous pattern, this type of pattern is not associated with scleroderma. Scleroderma is associated with a nucleolar staining pattern. The image presented is a homogeneous or diffuse ANA staining pattern, not a nucleolar staining pattern. A nucleolar pattern is characterized by smooth staining in the nucleus of the interphase cells (a). The nucleoli may or may not stain. The chromosomal area of the metaphase mitotic cells is negative (b). A nucleolar pattern can be associated with Sjogren's syndrome, scleroderma, or SLE. The image presented is a homogeneous or diffuse ANA staining pattern, not a peripheral staining pattern. In a peripheral or rim pattern, the central staining protein of the nucleus is only lightly stained or not stained at all, but the nuclear margins fluoresce strongly and appear to extend into the cytoplasm. A peripheral pattern is associated with SLE in an active stage or Sjorgen's syndrome.

All of the listed disorders are organ non-specific autoimmune diseases EXCEPT: - Systemic lupus erythematosus (SLE) - Systemic sclerosis (SSc) - Rheumatoid arthritis (RA) - Hashimoto's disease

- Hashimoto's disease Hashimoto's disease or Lymphoid Chronic Thyroiditis is an endocrine disorder and a classic example of an organ-specific autoimmune disease. In this example, the autoimmune process in which the development of circulating cytotoxic antibodies eventually destroy the thyroid gland and produce hypothyroidism. Organ-specific, autoimmune disease are produced by T cells or antibodies against antigens restricted to a single organ. In organ-specific diseases both the lesions produced by tissue damage and the auto-antibodies are directed at the same organ. Systemic lupus erythematosus (SLE) is a classic example of a systemic autoimmune disease produced by circulating antibodies or immune complexes and affects multiple end organs. The terms, systemic, refers to multiple systems in the body. Organ nonspecific diseases are characterized by the presence of both lesions and autoantibodies that are not confined to any single organ. Systemic sclerosis (SSc), Progressive Systemic Sclerosis, or Scleroderma is a collagen vascular disease. Idiopathic scleroderma is considered an autoimmune disease because of the associated autoantibodies and the overlapping syndromes of scleroderma-polymyositis and scleroderma-SLE. The term, rheumatic disease, does not have a clear boundary with more than 100 different conditions being labeled as rheumatic diseases, including rheumatoid arthritis (RA). RA is a chronic, multi-system, autoimmune disorder a progressive inflammatory disorder of the joints. The current model of the pathogenesis of RA proposes that an infective agent or other stimulus binds to receptors on dendritic cells, that activate the innate immune system.

False positive results for HIV antibody are most likely to occur in patients that: - Have been exposed to HIV very recently - Are receiving immunosuppressive therapy - Have an autoimmune disorder - Are infected with a genetically rare strain of HIV

- Have an autoimmune disorder False positive results for HIV antibody are most likely to occur in patients that have an autoimmune disorder, as these patients can produce autoantibodies that exhibit cross-reactivity in HIV serology tests. Patients that have been exposed to HIV very recently may not have had sufficient time to develop detectable HIV antibodies, leading to false negative test results. False negative results can also occur in patients receiving immunosuppressive therapy or in those infected with a rare strain of HIV that is not detected by routinely used serology tests for HIV antibody.

B lymphocytes and T lymphocytes are derived from: - Hematopoietic stem cells - Macrophages or monocytes - Mucosa-associated lymphoid tissue (MALT) - Granulocytes

- Hematopoietic stem cells All lymphocytes originate, and are therefore derived from, hematopoietic stem cells via hematopoiesis. The stem cells eventually mature into common lymphoid progenitor cells. The progenitor cells then differentiate into their distinct lymphocyte types. B cells mature into B lymphocytes in the bone marrow, while T cells migrate to and mature in the thymus.

All of the following diseases are associated with autoantibodies, EXCEPT? - Wegener's disease - Rheumatoid arthritis - Systemic lupus erythematosus - Hemolytic disease of the newborn

- Hemolytic disease of the newborn HDN is associated with alloantibodies from the mother's bloodstream directed against the baby's red cell antigens. An infant is not capable of producing antibodies until 6 months of age. Wegener's disease is a condition that affects the vascular system with autoantibodies formed against neutrophil cytoplasmic antigens. Rheumatoid arthritis is a systemic disorder in which auto-antibodies are formed against IgG. Systemic lupus erythematosus (SLE) is also a systemic disorder in which several types of antinuclear autoantibodies are formed.

Which of the following blood tests can be collected in a serum separation tube (SST)? - CBC - Hepatitis B surface antigen (HBsAg) - PT - ABO group and Rh typing

- Hepatitis B surface antigen (HBsAg) Hepatitis B surface antigen (HBsAg) is a serological test meant to help in the diagnosis of acute hepatitis B. It should be collected in a Serum Separation Tube (SST) and spun immediately to have serum separated from the cells. CBC and ABO group and Rh typing should be collected in EDTA tubes. PT should be collected in sodium citrate tube (light blue).

What Anti-Nuclear Antibody (ANA) staining pattern is presented in the microscopic image? - Speckled - Centromere - SSA/Ro - Homogeneous

- Homogeneous A homogeneous or diffused pattern is correct. This pattern characterizes anti-DNA nucleoprotein antibodies (i.e., antibodies to nDNA, dsDNA, ssDNA, DNP, or histones). The antinuclear antibody (ANA) test pattern that is seen in this image, viewed using fluorescent microscopy, is characterized by smooth staining in the nuclei of the interphase cells (a) and smooth staining in the chromosomal areas of the metaphase mitotic cells (b). The nucleoli may or may not stain. Although vacuoles may be seen, the whole nucleus fluoresces evenly. Notice the smooth staining in the chromosomal areas of the metaphase mitotic cells (b). In order for the ANA to be positive, there must be a clearly discernible pattern in the nuclei of the interphase cells. Note: (a) points to the nuclei of two interphase cells. the nucleus of the interphase cell is the primary consideration for discerning the ANA pattern. (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in the identification of the ANA pattern. Metaphase mitotic cells are used to assist in the identification of the ANA pattern. This pattern is typically seen in rheumatoid disorders. High titers of homogeneous ANA suggest Systemic Lupus Erythematosus (SLE); low titers may be found in SLE, Rheumatoid arthritis, Sjorgen's syndrome, and mixed connective tissue disease. The speckled pattern occurs in the presence of antibodies to any extractable nuclear antigen devoid of DNA or histone. The antibody is detected against the saline extractable nuclear antigens, anti-RNPand anti-Sm. A grainy pattern with numerous round dots of nuclear fluorescence, without staining of the nucleoli, is seen in this pattern type. Antibodies to anti-RNP have been found in patients with a wide variety of rheumatic disorders , including SLE. Antibodies to Sm antigen have been shown to be highly specific for patients with systemic lupus erythematosus (SLE). The anticentromere antibody reacts with centromeric chromatin of metaphase and interphase cells. The particular pattern on tissue culture cells is discrete and speckled. This antibody is found infrequently in the serum of patients with systemic lupus erythematosus (SLE). Anti-Ro (SS-A) antibody is included in the nonhistone protein (NhPs) and NhP-RNA complexes in systemic rheumatic disease. The incidence of the antibody is 50% in cases of SLE. Detection of antibodies to SS-A/Ro varies according to the fixation method. alcohol diminishes or destroys the SS-A/Ro speckled ANA pattern, leading to a negative ANA.

The Major Histocompatibility Complex (MHC) I genes encode for: - Human Leukocyte Antigens (HLA)-A,B,C - Human Leukocyte Antigens (HLA)-DR,DQ,DP - Complement - Cytokines

- Human Leukocyte Antigens (HLA)-A,B,C MHC I codes for HLA-A,B,C MHC II codes for HLA-DR,DQ,DP MHC III codes for complement MHC III codes for cytokines

All of the following are advantages of HEp-2 and HEp-2000® over rodent tissue as cell substrates for ANA testing, EXCEPT? - Human cell lines are more sensitive than rodent - Human cell lines do not express Ro (SS-A) antigen - Human cell lines express relevant nuclear antigens in the human tumor cell - Nucleolar reactivity is detectable in human cell lines

- Human cell lines do not express Ro (SS-A) antigen Human cell lines do express Ro (SS-A) antigen, contributing to the sensitivity of the test. Human cell lines such as HEp-2 and HEp-2000 are considered the gold standard as they are more sensitive than rodent lines for detection of ANAs. Human cell lines do express relevant nuclear antigens in the human tumor cell that may not be found in rodent tissue. Nucleolar reactivity is detectable in human cell lines and may not be readily detected in rodent tissue.

All of the following are true about hybridization in PCR procedures, EXCEPT? - Hybridization cannot happen between a strand of DNA and a strand of RNA - Hybridization is the process of single strands of nucleic acid bonding together to form double strands - Hybridization can also be called annealing - Complementary bases link together with hydrogen bonds

- Hybridization cannot happen between a strand of DNA and a strand of RNA Hybridization or annealing is the process of binding known nucleic acid strands to the unknown for synthetization of complementary strands. This can occur between a strand of DNA and a strand of RNA. Complementary bases link by hydrogen bonds to create the DNA double helix. The process of complementary single strands of DNA to form into double stranded DNA is called hybridization or annealing.

Rocky Mountain spotted fever (RMSF), caused by Rickettsia rickettsii, is MOST reliably diagnosed by which laboratory technique? - Blood culture - Electron microscopy - IFA testing - Serial dilution

- IFA testing The gold standard for diagnosis of RMSF is the indirect immunofluorescence antibody (IFA) assay with R. rickettsii antigen, demonstrating a significant (four-fold) rise in antibody titer in two serum samples. Timing of the samples should be at onset of symptoms, and within a few weeks, allowing time for antibodies to develop. However, treatment should be initiated before confirmation. Blood culture, electron microscopy, and serial dilution are not usual methods for confirming RMSF.

A major macrophage-activating cytokine is: - IFN-? (Interferon gamma) - Interleukin 3 (IL-3) - Interleukin 4 (IL-4) - Interleukin 5 (IL-5)

- IFN-? (Interferon gamma) The sources of IFN-??are TH1lymphocytes, cytotoxic T cells, and natural killer (NK) cells. IFN-? is associated with innate and adaptive immunity. It is a major macrophage-activating cytokine and serves a critical function in innate immunity and in cell-mediate immunity. IFN-? induces MHC class II molecules on many cells and can synergize with tumor-necrosis factor (TNF). It also augments NK cell activity and is an antagonist to IL-4. The origin of the cytokine, IL-3 (formerly multicolony-stimulating factor), is activated T cells. It promotes expansion of early blood cells (hematopoiesis) that differentiate into all known mature cell types. IL-3 supports growth and differentiation of T lymphocytes from bone marrow through immune responses. The origin of the cytokine, IL-4, is helper T cells (TH2), and mast cells. IL-4 is a key regulator of humoral and adaptive immunity. IL-4 induces differentiation of naive helper T cells (TH0) to TH2cells . The origin of the cytokine, IL-5, is TH2 and mast cells. IL-5 is associated with adaptive immunity. The principal function of IL-5 is to activate eosinophils and serve as a link between T cell activation and eosinophilic inflammation.

Examples of cytokines originating from activated T-cells include: - IL-3, IL-8 - IL-18, IL-19 - IL-1 superfamily, IL-2 - IL-2, IL-3

- IL-2, IL-3 IL-2, IL-3 are cytokines previously called T-Cell growth factor (IL-2) and Multicolony stimulating factor (IL-3), and are two of the known cytokines that originate from activated T-cells. IL-22 is another cytokine originating in activated T-cells. IL-2 is associated with adaptive immunity. It has a high capacity to induce activation of almost all clones of cytotoxic cells, increase the cytotoxic function of T killer and NK cell, promote production of perforins and gamma interferon. In addition, it activates monocytes-macrophages. IL-3 promotes the expansion of early blood cells (hematopoiesis) that differentiate into all known mature cell types. IL-3 also supports the growth and differentiation of T cells from bone marrow through an immune response. IL-3 originates from activated T cells, but IL-8 does not. IL-8 originates from macrophages and certain types of epithelial cells, e.g. endothelium. IL-18 originates from macrophages, and IL-19 originates from monocytes. IL-2 originates from activated T cells, but IL-1 superfamily originates from monocytes, activated macrophages, fibroblasts, and dendritic cells.

The most frequently encountered immunoglobulin demonstrated in patients with Multiple Myeloma is: - IgM - Ig G - Ig A - IgE

- Ig G The most commonly encountered form of immunoglobin in patients suffering from Multiple Myeloma is IgG at 52%. Four subtypes of IgG heavy chains are known to exist among patients with IgG myeloma (IgG1, IgG2, IgG3, IgG4). The subclasses of cases of IgG myeloma are distributed as follows: 65% gamma G1, 23%IgG2, 8% IgG3, 4% IgG. IgM occurs in 12% of patients with Multiple Myeloma. Ig A occurs in 22% of patients with Multiple Myeloma. IgE is rarely detected in patients with Multiple Myeloma.

Which antibody class is best described with that characteristic that it is the only one capable of residing in mucosal linings? - IgA - IgM - IgG - IgE

- IgA The five distinctive heavy-chain molecules distinguish the antibody class of isotype. Each heavy chain imparts characteristic features, which permit them to have unique biological functions. IgA, which possesses alpha heavy chains, is the only antibody class capable of residing in mucosal linings. Both IgM and IgG can activate complement. IgM is the largest immunoglobulin, as it is a pentamer. IgG immunoglobulins have the ability to cross the placental barrier. Finally, immediate hypersensitivity reactions are associated with IgE immunoglobulins.

The antibody mediator associated with a Type I Hypersensitivity Reaction is: - IgM - IgG - IgA - IgE

- IgE A Type I Hypersensitivity Reaction is associated with IgE. The mast cell carries high-affinity receptors for the Fc portion of IgE. Allergen-specific IgE, occupying these receptors, induces mast cell degranulation immediately after allergens are encountered. IgM and IgG are not associated with a Type I Hypersensitivity Reaction but can be associated with immune complex Type III Hypersensitivity Reactions. IgG and possibly other immunoglobulins are not associated with a Type I Hypersensitivity Reaction but can be associated with cytotoxic, Type II Hypersensitivity Reactions. IgA is not associated with any Hypersensitivity Reaction. The functional characteristics of IgA are mucosal immunity and defense of external body surfaces.

Which immunoglobulin is associated with anaphylactic shock? - IgA - IgD - IgE - IgG

- IgE IgE is associated with anaphylaxis. It promotes mast cell degranulation in immediate hypersensitivity reactions. Type I hypersensitivity reactions can range from life-threatening anaphylactic reactions to milder manifestations associated with food allergies. Anaphylaxis results from degranulation of mast cells or basophils mediated by IgE. The IgE molecule is unique in that it binds strongly to a receptor or mast cells and basophils and, together with antigen, mediates the release of histamine and heparin from these cells. IgA is associated with mucosal immunity. It defends external body surfaces and is secreted into the lumens of the gastrointestinal and respiratory tracts. IgD is important for B-cell activation and/or immunoregulation. IgG has multiple functions, including opsonization of antigens for phagocytosis by macrophages and neutrophils.

Antibodies of which of the following immunoglobulin subclasses is predominantly associated with the secondary antibody response? - IgA - IgD - IgG - IgM

- IgG IgG antibody production is stimulated in the secondary immune response and demonstrates a rapid and strong response to secondary exposure to the corresponding antigen. The IgA immunoglobulin subclass is associated with severe anaphylactic reactions when IgA is transfused in plasma-containing products to IgA deficient recipients. The IgD immunoglobulin can impact the maturation of B cells into plasma cells but is the least significant immunoglobulin subclass in immunohematology. The primary immune response to a foreign antigen is characterized by a lag period and the initial production of IgM antibodies.

Which of the following antibody types is the predominant serum antibody seen in the secondary immune response: - IgG - IgA - IgM - IgD

- IgG In primary responses, the first and predominant major class of antibody produced is IgM. In the secondary response, IgG is produced quickly and becomes the predominant antibody. IgA is not seen as a predominant antibody in the serum, however, it is found as the predominant antibody in the mucosa. In primary responses, the first and predominant major class of antibody produced is IgM. In the secondary response, IgG is produced quickly and becomes the predominant antibody. IgD is found primarily in B lymphocytes and does not play a major role in serum immune responses.

What characteristic differentiates a secondary immune response from a primary immune response? - IgM is the predominant antibody class produced in the secondary immune response compared to the primary immune response. - The IgG antibody levels produced are lower in the secondary immune response than in a primary immune response. - The lag phase of IgM and IgG antibody development is longer in the secondary immune response than in a primary immune response. - IgG is the predominant antibody class produced in the secondary immune response compared to the primary immune response.

- IgG is the predominant antibody class produced in the secondary immune response compared to the primary immune response. The important comparative characteristics of a secondary immune response are: IgG is the predominant antibody class produced in the secondary immune response. The IgG antibody level is higher in the secondary immune response. The lag phase (the time between exposure to antigen and production of antibody) is shorter in the secondary immune response. The primary immune response is characterized by a predominance of IgM antibodies rather than IgG. IgM is not the predominant antibody class produced in the secondary immune response compared to the primary immune response. The IgG antibody levels produced are higher in the secondary immune response than in a primary immune response. The lag phase of IgM and IgG antibody development is shorter in the secondary immune response than in a primary immune response.

Which of the following antibody types is chiefly seen in the primary immune response: - IgG - IgA - IgM - IgD

- IgM IgM is the main immunoglobulin seen in the primary immune response, after the first exposure to an antigen. IgG is chiefly seen in the secondary immune response or the memory response produced upon a second or subsequent exposure to an antigen. IgA is the predominant immunoglobulin in body secretions. Finally, IgD is found in very small quantities and accounts for less than 1% of the total immunoglobulin pool.

All of the following conditions are associated with a polyclonal (broadbased) increase in gamma globulins except? - Liver disease - Chronic inflammation - Immune reaction - Immunodeficiency

- Immunodeficiency Immunodeficiency would, of course, generally be associated with a decrease in serum immunoglobulin levels, and an associated decreased gamma band. Polyclonal increases are associated with infection, inflammation, liver disease, rheumatoid diseases, and lymphoproliferative disorders.

In an autoimmune disorder, conditions influencing the development of a disorder include the following factors with the exception of: - Genetic factors - Exogenous factors - Immunopathogenic mechanisms - Increased discrimination of self from non-self antigens

- Increased discrimination of self from non-self antigens Decreased rather than increased discrimination of self from non-self antigens is the dysfunction in autoimmunity. Autoimmunity represents a breakdown of the immune system's ability to discriminate between "self" and "nonself." The term autoimmune disorder refers to a varied group of chronic illnesses that involve almost every human organ system. In all of these disorders, the underlying problem is similar: the body's immune system becomes misdirected, attacking the organs it was designed to protect. An autoimmune disorder is usually prevented by the normal functioning of immunologic regulatory mechanisms. When these controls dysfunction, antibodies to "self" antigens may be produced and bind to antigens in the circulation to form circulating immune complexes or to antigens deposited in specific tissue sites. Genetic factors are a risk factor for the development of an autoimmune disorder. Any genetic change that reduces deletion or enhances activation of autoreactivity may be a risk factor for the development of an autoimmune disorder. The association of genetics and autoimmune disorders focuses on common allelic variants, not mutations. In autoimmune disorders, there is a tendency for familial aggregates to occur. In addition, there is a tendency for more than one autoimmune disease to occur in the same individual. Another factor related to genetic inheritance is that autoimmune disorders and autoantibodies are found more frequently in women than in men. Exogenous factors are risk factors for the development of an autoimmune disorder. Ultraviolet radiation, drugs, viruses, and chronic infectious disease may all play a role in the development of autoimmunity. These factors may alter antigens, which the body then perceives as nonself antigens. Immunopathogenic mechanisms are risk factors for the development of an autoimmune disorder. Autoimmune disorders are usually prevented by the normal functioning of immunologic regulatory mechanisms. If these controls malfunction, antibodies to self-antigens may be produced and bind to antigens in the circulation to form circulating immune complexes or to antigens deposited in specific tissue sites. Wherever antigen-antibody complex accumulate, complement can be activated, with the subsequent release of mediators of inflammation.

All of the following are features of systemic lupus erythematosus (SLE), EXCEPT: - Increased serum complement - Positive ANA - Circulating immune complexes - Elevated erythrocyte sedimentation rate

- Increased serum complement Serum levels of complement are actually decreased (not increased) in active cases of systemic lupus erythematosus (SLE) because complement is consumed during the immune reactions involved in the disease. Anti-nuclear antibodies (ANA) and circulating immune complexes consisting of auto-antibodies bound to their respective antigens are found in the majority of patients with SLE. The erythrocyte sedimentation rate, an indicator of inflammation, may be elevated in SLE as well.

The classic TORCH panel of tests includes the following diseases with the exception of: - Rubella - Toxoplasma gondii - Infectious mononucleosis - Cytomegalovirus

- Infectious mononucleosis Infectious mononucleosis is not in the TORCH grouping of assays. The TORCH panel is an acronym for Toxoplasma gondii; other viruses, rubella, cytomegalovirus, and herpes viruses. It is important in diseases that do not manifest decisive clinical signs and symptoms, or under conditions in which a rapid therapeutic decision may be required. TORCH specifically evaluates the presence of IgM or IgG. This panel is used to screen newborns, and sometimes, pregnant women for certain infections that can cause birth defects.

The vast MAJORITY of would-be invaders are killed or inactivated primarily by which part of the immune system? - Cell mediated immunity - Specific immunity - Humoral immunity - Innate immunity

- Innate immunity The innate immunity system is inherent and nonspecific; meaning that all pathogens are attacked similarly. The skin, mucus in respiratory tracts, acid pH, and others are all examples of the innate immunity system that the body has to prevent infection upon first exposure. Cell mediated immunity is part of the specific or adaptive immunity system that will react when pathogens breach the initial barriers of the inmate immune system. Specific immunity, also called adaptive or acquired immunity, is a result of a pathogen breaching one of the inmate barriers, being processed by antigen processing cells resulting in a cell mediated, humoral response, or both. Humoral immunity is the aspect of immunity that is mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides. Humoral immunity is so named because it involves substances found in the humors, or body fluids.

Which of the following is correct regarding C-reactive protein (CRP)? - Is a highly specific test - Corresponds to serum complement levels - Is usually elevated in pediatric bacterial infections - Does not react with pneumococcal C-polysaccharide

- Is usually elevated in pediatric bacterial infections C-reactive protein was first found to precipitate pneumococcal C-polysaccharide in patients who had recovered from pneumococcal pneumonia. It was subsequently found to be elevated in numerous other conditions. It is often elevated in pediatric bacterial infections, and usually not elevated in pediatric viral infections, and thus may help the pediatrician to differentiate these entities. It can also be used to follow the disease activity in autoimmune conditions.

All of the following is true about real-time RT-PCR, EXCEPT? - It is the most sensitive method for evaluating RNA - It requires the least amount of initial product - It does not require the use of reverse transcriptase - Can detect infection before antibodies appear

- It does not require the use of reverse transcriptase PCR does require reverse transcriptase to create a copy of DNA from the original RNA specimen. PCR is highly sensitive in detecting RNA because is amplifies what is present to make it able to be detected and measured. PCR can use a sample of less than 1 mL for testing. PCR is highly sensitive and can detect infection in individuals before antibodies appear.

The immunoglobulin molecule is made up of both heavy and light chains - the light chains can be comprised of which of the following? - Alpha or beta - Alpha or lambda - Kappa or beta - Kappa or lambda

- Kappa or lambda Only kappa or lambda chains can compose the light chains of an immunoglobulin molecule. Each chain contains between 200 and 220 amino acids.

Identify a characteristic of an organ-non specific disorder that distinguishes it from an organ specific disorder. - Lesions caused by deposition of antigen-antibody immune complexes - Antigens only available to lymphoid system in low concentrations - Lymphoid invasion, parenchymal destruction by questionable cell-mediated hypersensitivity or antibodies - Tendency to develop cancer in a specific location of the body

- Lesions caused by deposition of antigen-antibody immune complexes In organ non-specific disorders, lesions are caused by the deposition of antigen-antibody immune complexes. Immune complexes are formed from the binding of an antibody to an antigen. An immune complex deposition is an associated feature of several autoimmune diseases, including systemic lupus erythematosus (SLE), cryoglobulinemia, rheumatoid arthritis, scleroderma, and Sjögren's syndrome. Antigens are only available to the lymphoid system in low concentrations in organ-specific disorders. In organ non-specific disorders, antigens are accessible at higher concentrations. Lymphoid invasion, parenchymal destruction by questionable cell-mediated hypersensitivity, or antibodies occurs in organ-specific disorders. In comparison, organ non-specific disorders exhibit lesions caused by deposition of antibody (immune) complexes. A tendency to develop cancer in a specific location of the body is associated with organ-specific disorders. In organ non-specific disorders, the comparative characteristic is that there is a tendency to develop lymphoreticular neoplasia.

What part of an immunoglobulin (Ig) molecule exists as kappa or lambda chains? - Fc - Fab - Heavy chains - Light chains

- Light chains All immunoglobulins have a common, basic polypeptide structure with a three-dimensional configuration. The polypeptide chains are linked by covalent and noncovalent bonds, which produce a unit composed of a four-chain structure based on pairs of identical heavy and light chains. There are two types of light (L) chains: kappa (?)or lambda (?), which are common to all Ig classes. The L chain subtypes have different amino acid sequences and are antigenically different. In human beings, about 65% of Ig molecules have kappa chains, and about 35% have lambda chains. The larger H chains extend the full length of the molecules. IgG, IgD, and IgE occur only as monomers of the four-chain unit; IgA occurs in both monomeric and polymeric forms, and IgM occurs as a pentamer with five four-chain subunits linked together. Fc is the third fragment formed in addition to the two Fab fragments if a typical monomeric IgG is digested with a proteolytic enzyme. This fragment is relatively homogeneous and sometimes crystallizable. The Fc receptor is the portion of the Ig molecule responsible for binding to antibody receptors on cells and the C1q component of complement. Fab fragments are two of the three fragments formed if a typical monomeric IgG is digested with a proteolytic enzyme. These fragments retain the ability to bind antigens, specific receptors on cells, and are called antigen-binding fragments. Fab is composed of two light chains, and portions of two heavy chains joined by disulfide bonds in the hinge region of Ig. Heavy (H) chains extend the full length of an immunoglobulin (Ig) molecule. In addition, each monomer of an immunoglobulin consists of two heavy chains paired with two light chains. the first 110 to 120 amino acids of both L and H chains a variable sequence that forms the V region of the Ig. The remaining portion of the H chain is constant for each type of Ig. The class and subclass of an immunoglobulin molecule are determined by its H-chain type.

Nephelometry involves the measurement of: - Light absorption - Light transmission - Light scatter - Atomic absorption

- Light scatter When light strikes a particle in a solution, it can be absorbed, transmitted, reflected, or scattered. Nephelometry is used to measure the light scattered by particles in a solution. It is useful for measuring protein levels in fluids, and antigen-antibody complexes.

Nephelometry and turbidimetry measure different properties of: - Fluorescence in turbid solutions - Free ions in solution - UV light at 360 nm - Light transmission and scatter by particles in suspension

- Light transmission and scatter by particles in suspension When light strikes a particle in a solution, it can be absorbed, transmitted, reflected, or scattered. Nephelometry is used to measure the light scattered by particles in a solution. Turbidimetry measures the light transmitted by particles in a solution. These are useful techniques for measuring protein levels in fluids and antigen-antibody complexes.

What is the primary target of HBV? - Heart - Liver - Lungs - Brain

- Liver The liver is the primary target organ for the Hepatitis B virus (HBV). The inflammation caused by HBV can result in permanent liver damage, including cirrhosis, liver failure, and even hepatocellular carcinoma. The infection presents as acute or chronic hepatitis with a pathologic effect on the liver (not heart, lungs, or brain), resulting in self-limited or fatal outcomes.

The late steps of complement activation and formation of the "membrane attack" complex (MAC) results in: - Immune complex removal - Lysis of cells - Opsonization in phagocytosis - Polymorphonuclear (PMN) leukocyte activation

- Lysis of cells Lysis of cells is the result of the late steps of complement activation and formation of the "membrane attack" complex (MAC). When fully assembled in the correct proportion, C7, C6, C5b, and C8 form the MAC. The C5bC6C7C8 complex polymerizes C9 to form a tubule (pore) which spans the membrane of the cell being attacked, allowing ions to flow freely between the cellular interior and exterior. By complexing with C9, osmotic cytolysis Removal of an immune complex from tissues occurs with the activation of classic complement components C1q and covalently bonded fragments of C3 and C4. Opsonization in phagocytosis is facilitated by covalently bonded fragments of C3 and C4. Activation of polymorphonuclear (PMN) leukocytes is facilitated by C5a, C3a, and C4a.

Antigen processing is primarily accomplished by what type of cells? - Basophils - Eosinophils - Polymorphonuclear neutrophils - Macrophages

- Macrophages Antigen-presenting cells (APCs) are a group of functionally defined cells capable of taking up antigens and presenting them to lymphocytes in a form that these cells can recognize. APCs include macrophages, dendritic cells, B cells and even tissue cells. Macrophages along with the network of reticular cells of the spleen, thymus, and other lymphoid tissues, are organized into the mononuclear phagocyte systems. Kupffer cells are specialized macrophages located in the liver, lining the walls of the sinusoids that form part of mononuclear phagocyte system. Functionally, monocytes-macrophages have phagocytosis as their major role, but these cells perform at least three distinct but interrelated functions in host defense. The categories of host defense functions of monocytes-macrophages include phagocytosis, antigen presentation and induction of the immune response, and secretion of biologically active molecules. The phagocytic property of the macrophage is particularly important in the processing of antigens as part of the immune response. After digesting a pathogen, a macrophage will present the antigen on its cell surface to the corresponding helper T cell. The presentation is done by integrating it into the cell membrane and displaying it attached to an MHC class II molecule, indicating to other white blood cells that the macrophage is not a pathogen, despite having antigens on its surface Basophils are capable of participating in phagocytosis but they possess less phagocytic activity and do not process antigens. . The ineffectiveness of cells results from the very small number of cells in the circulating blood and lack of powerful digestive enzymes. Basophils are functionally important in body defense in the acute, systemic, hypersensitivity reactions. Eosinophils are capable of participating in phagocytosis but they do not process antigens. The ineffectiveness of cells results from the small number of cell in the circulating blood and lack of powerful digestive enzymes. The eosinophil is considered a homeostatic regulator of inflammation. The eosinophil may also play a role in the host defense mechanism because of its ability to kill certain parasites such as Schistosoma. Polymorphonuclear neutrophils (PMNs)are particularly effective in host defense against bacterial and fungal infections. The antimicrobial function is essential in the innate immune response. PMNs do not process antigens.

A cause of FALSE-POSITIVE result in the rapid plasma reagin (RPR) test for syphilis is: - Gastroenteritis - Gonococcal urethritis - Malaria - Streptococcal pharyngitis

- Malaria The RPR test can show false positive results in the absence of syphilis if infectious mononucleosis, SLE, antiphospholipid antibody syndrome, hepatitis A, leprosy, or malaria are present. The RPR test results may also be positive due to other treponemal diseases such as pinta and yaws. Gastroenteritis, gonococcal urethritis, or streptoccocal pharyngitis do not produce false-positive RPR reactions.

CD5 antigen is normally found on which of the following lymphocyte populations? - Mature T cells - Normal B cells - Both mature T cells and normal B cells - None of the above, CD5 is not a lymphoid marker

- Mature T cells The cluster of differentiation or CD system was developed to identify antigens on the surface of blood cells using monoclonal antibodies in flow cytometry. CD5 is a lymphoid marker present on mature T cells but is not present on normal B cells.

When evaluating the patterns of fluorescent anti-nuclear antibody (FANA) testing, cytoplasmic patterns: - Are not considered in pattern assessment - May demonstrate anti-mitochondrial antibodies seen primary biliary cirrhosis - Indicate the presence of anti-histone antibodies - Indicate the presence of anti-Smith antibodies

- May demonstrate anti-mitochondrial antibodies seen primary biliary cirrhosis Anti-mitochondrial antibodies have been associated with primary biliary cirrhosis, and the patterns are found in the cytoplasm of cells in the FANA preparation. Positive patterns in the cytoplasm in FANA should be considered and reported as they may be associated with organ-specific autoimmune conditions. Antihistone antibodies are present in the nucleus and are seen in diffuse or homogeneous FANA patterns. Anti-Smith antibodies are associated with speckled patterns in FANA testing.

What is the purpose of the Total Complement Activity (CH50) assay? - Measures classic or terminal complement pathways - Detects a deficiency in factor B, factor D, or properdin - Detects a Lectin pathway component deficiency - Measures the alternative complement pathway

- Measures classic or terminal complement pathways The most frequent initial evaluation of complement for a suspected complement deficiency includes testing for both the classic (CH50) and alternative (AH50) pathways. Total Complement Activity (CH50) assay is the best screening test for deficiency of classic or terminal complement pathways. Initial testing may also include mannose-binding lectin testing, depending on the clinical circumstances. Hemolytic activity of the complement system is measured as hemolysis of sheep erythrocytes sensitized by specific antibodies. The degree of hemolysis is measure by CH50. One CH50 unit is defined as the volume or dilution of serum that lyses 50% of erythrocytes in the reaction mixture. A low level of CH50 suggests deficiency of a classic or terminal complement component. A deficiency in factor B, factor D, or properdin is detected by the alternative (AH50) complement pathway. A low level of both CH50 and AH50 suggests a deficiency of one of the components shared by both pathways, e.g. C3-C9. Detection of a Lectin pathway component deficiency is initially detected by the Mannose-binding lectin testing depending on the clinical circumstances. The alternative (AH50) complement pathway measures alternative-pathway complement function. This test is available only in specialized laboratories. A low level of AH50 detects a deficiency in factor B, factor D, or properdin.

Class II Major Histocompatibility Complex genes encode for: - Molecules that present antigen to CD8+ T cells - Molecules that present antigen to CD4+ T cells - Complement molecules - Cytokine molecules

- Molecules that present antigen to CD4+ T cells Class II Major Histocompatibility Complex genes encode for molecules that present antigen to CD4+ T cells. Molecules that present antigen to CD8+ T cells are encoded by class I MHC genes. Complement molecules are encoded by class III MHC genes. Cytokine molecules are encoded by class III MHC genes.

Tumor markers are especially valuable when used to: - Rule out cancer - Screen the general population for cancer - Monitor response to cancer therapy - Confirm other assays

- Monitor response to cancer therapy Tumor markers are substances produced by either a tumor or as a response by the healthy tissue to a tumor. While sometimes used for other purposes, tumor markers are generally most valuable for evaluating progression of the disease and for monitoring response to cancer treatment. Tumor markers represent a diverse group of molecules which include serum proteins, hormones, receptors, enzymes, oncofetal antigens, and metabolites.

Which of the following BEST describes the relation of nephelometry to turbidimetry? - Nephelometry measures the amount of light absorbed by particles in solution, and turbidimetry measures the amount of light transmitted through a solution - Nephelometry directly measures the amount of light scattered by particles in solution, and turbidimetry measures the decrease in incident-light intensity - Nephelometry measures the amount of light emitted by particles in solution, and turbidimetry measures the amount of light reflected by particles in solution - Nephelometry measures the amount of light absorbed, and Turbidimetry measures the amount of light scattered

- Nephelometry directly measures the amount of light scattered by particles in solution, and turbidimetry measures the decrease in incident-light intensity The best description of nephelometry to turbidimetry is: nephelometry directly measures the amount of light scattered by particles in solution, and turbidimetry measures the decrease in incident-light intensity. In other words, nephelometry refers to the way a nephelometer measures how much light is scattered by suspended particles in the water. The greater the scattering, the higher the turbidity. These are useful techniques for measuring protein levels in fluids and antigen-antibody complexes.

The antibody most frequently present in systemic lupus erythematosus (SLE) patients is directed against: - Myelin - Nuclear antigen - Surface antigens of bone marrow stem cells - Surface antigens of renal cells

- Nuclear antigen The anti-nuclear antigen test, or ANA test, is a valuable screening tool for systemic lupus erythematosus (SLE). Demonstration of ANAs can indicate various systemic autoimmune connective tissue disorders characterized by antibodies that react with different nuclear components such as double stranded DNA, single-stranded DNA, and Sm (Smith) antigen. ANAs are classified into antibodies to DNA, antibodies to histones, antibodies to nonhistone proteins, and antibodies to nuclear antigens. Antimyelin-associated glycoprotein is associated with chronic sensorimotor demyelinating neuropathy. Various hematologic conditions can be caused by alloantibodies or autoantibodies. Antibodies associated with autoimmune conditions can be secondary to Mycoplasma pneumoniae infection, viral infections , lymphoma, or drugs. Immunologic renal disease can be associated with four categories of diseases, one of which is circulating immune complexes. Renal diseases associated with circulating immune complexes are caused by nonrenal antigens and their corresponding antibodies. Studies have suggested that potentially damaging immune complexes may be formed in situ and involve antigens already present or fixed in the glomerulus. In addition, immune complex activation of complement in the glomerular basement membrane may be augmented by the presence of cells with receptors for C3 located in that area. Activation probably releases biologically active products such as chemotactic substances and causes an inflammatory type of tissue injury. A renal complication of this type can be manifested in SLE. Neuropathy syndromes are associated with antibodies directed against peripheral nerve components. For example, the antibody antimyelin-associated glycoprotein is associated with chronic sensorimotor demyelinating neuropathy. Various hematologic conditions can be caused by alloantibodies or autoantibodies. Antibodies associated with autoimmune conditions can be secondary to Mycoplasma pneumoniae infection, viral infections, lymphoma or drugs. Immunologic renal disease can be associated with four categories of diseases, one of which is circulating immune complexes. Renal diseases associated with circulating immune complexes are caused by nonrenal antigens and their corresponding antibodies. Studies have suggested that potentially damaging immune complexes may be formed in situ and involve antigens already present or fixed in the glomerulus. In addition, immune complex activation of complement in the glomerular basement membrane may be augmented by the presence of cells with receptors for C3 located in that area. Activation probably releases biologically active products such as chemotactic substances and causes an inflammatory type of tissue injury. A renal complication of this type can be manifested in SLE.

Which test is NOT used as a screen for retroviruses in donated blood? - Antibody to HIV type 1 or type 2 - Nucleic acid testing to detect HIV-1 RNA - Antibody to HTLV types I and II - Nucleic acid testing for HCV

- Nucleic acid testing for HCV Three tests are currently used as a screen for retroviruses in donated blood: antibody to HIV type 1 or type 2 (anti-HIV-1/2), nucleic acid testing (NAT) to detect HIV-1 RNA, and antibody to HTLV types I and II (anti-HTLV-I/II). Positive results using NAT for HCV are approved by the FDA to confirm a reactive HCV antibody test. Also, hepatitis C is not considered a retrovirus.

This antinuclear antibody (ANA) test is viewed using fluorescent microscopy, which pattern is this? - Homogeneous - SSA/Ro - Nucleolar - Speckled

- Nucleolar This nucleolar pattern is characterized by staining in the nucleoli of the interphase cells (a). The nucleolar staining can display subtle variations in staining inside the nucleoli including smooth, speckled and clumpy. All are reported as ANA positive, Nucleolar. In this sample staining is present in the chromosomal area of the metaphase mitotic cells (b) along with some staining in the area outside of the chromosomal area. The staining of the mitotic cells can be different with different anti-nucleolar antibodies. An ANA pattern is determined by staining in the interphase cells and the mitotic cells are used to assist in interpretation. Note: (a) points to the nuclei of the interphase cells, the primary consideration for discerning the ANA pattern and (b) indicates a metaphase mitotic cell. Observing the chromosomal area and cytoplasm of the metaphase cell may assist in identification of the ANA pattern. A homogeneous or diffused pattern characterizes anti-DNA nucleoprotein antibodies (i.e. antibodies to nDNA, dsDNA, ssDNA, DNP or histones). A homogeneous pattern is characterized by smooth staining in the nuclei of the interphase cells and smooth staining in the chromosomal areas of the metaphase mitotic cells. The nucleoli may or may not stain. Although vacuoles may be seen, the whole nucleus fluoresces evenly. In order for the ANA to be positive there must be a clearly discernible pattern in the nuclei of the interphase cells. Anti-Ro (SS-A) antibody is included in the non-histone protein (NhPs) and NhP-RNA complexes in systemic rheumatic diseases. The incidence of the antibody is 50% in cases of SLE. Detection of antibodies to SS-A/Ro varies according to the fixation method. alcohol diminishes or destroys the SS-A/Ro speckled ANA pattern, leading to a negative ANA. A speckled pattern occurs in the presence of antibody to any extractable nuclear antigen devoid of DNA or histone. The antibody is detected against the saline extractable nuclear antigens, anti-RNP and anti-Sm. A grainy pattern with numerous round dots of nuclear fluorescence, without staining of the nucleoli, is seen in this pattern type. Antibodies to anti-RNP has been found in patients with a wide variety of rheumatic disorders , including SLE. Antibodies to Sm antigen have been shown to be highly specific for patients with systemic lupus erythematosus (SLE).

Which of the following types of lymphocytes express CD4? - Only T-helper cells - Only T-suppressor (cytotoxic) cells - All T cells - B cells

- Only T-helper cells T- helper cells express CD4. Neither T-suppressor cells nor B cells express CD4. CD3 is expressed by all mature T cells (helper and suppressor), but is not expressed by B cells.

Phagocytosis by cells of the mononuclear phagocytic system is greatly enhanced by which of the following? - Hemolysins - Opsonins - Specific antitoxins - Neutralizing antibodies

- Opsonins 'Opsonins' is the correct answer. An opsonin is a chemical substance that binds to antigens and increases the rate and quality of action by phagocytes to destroy invading microorganisms or particles. This process is called opsonization. In opsonization, the complement component C3b is attached to a particle, which promotes the adherence of phagocytic cells because of the C3 receptors. An antibody, if present, augments this process by binding the Fc receptors. Hemolysin is a substance such as streptolysin O produced by most group A streptococci that disrupt the membrane integrity of red blood cells, causing the release of hemoglobin. An antitoxin is an antibody that interlocks with and inactivates toxins (a poisonous substance)produced by certain bacteria. Neutralizing antibodies are antibodies that defend or neutralize the biological effect of a cell from an antigen or infectious microorganism by inhibiting or neutralizing any effect.

Important applications of polymerase chain reaction (PCR) include the following with the general exception of: - Search for mutations with large deletions - Amplification of DNA - Identification of a target sequence - Synthesis of an anti-sense probe

- Search for mutations with large deletions The search for mutations with large deletions in polymerase chain reaction (PCR) product sequence is not an application of the polymerase chain reaction (PCR)technique. In fact, it is a weakness. Only short sequences can be amplified (generally) Amplification of DNA is an important application of polymerase chain reaction (PCR) technique. PCR is a method that amplifies low levels of specific DNA sequences in a sample to higher levels suitable for further analysis. Identification of a target sequence is an important application of polymerase chain reaction (PCR) technique. Qualitative PCR detects the presence or absence of a specific DNA product. Synthesis of an anti-sense probe is an important application of polymerase chain reaction (PCR) technique. Antisense RNA is a single-stranded RNA that is complementary to a messenger RNA (mRNA) strand transcribed within a cell.

Two biologically functional characteristics of immunoglobin G (IgG) are: - First effective defense against bacteria; activation of the classical complement pathway. - Opsonization of antigens for phagocytosis by macrophages and neutrophils; neonatal immunity by transfer of maternal antibodies across the placenta and gut of the fetus. - Mucosal immunity, defends external body surfaces. - Provides protection against parasitic helminithic infection; mediates the release of histamines and heparin from mast cells and basophils.

- Opsonization of antigens for phagocytosis by macrophages and neutrophils; neonatal immunity by transfer of maternal antibodies across the placenta and gut of the fetus. Opsonization of antigens for phagocytosis by macrophages and neutrophils; neonatal immunity by transfer of maternal antibodies across the placenta and gut of the fetus are hallmark characteristics of IgG. In addition, it is the predominant antibody class in plasma or serum and combats microorganisms and their toxins in extravascular fluid. IgM is the first effective defense against bacteria; activation of the classical complement pathway. IgA functions in mucosal immunity to defend external body surfaces. IgE provides protection against parasitic helminthic infection; mediates the release of histamines and heparin from mast cells and basophils.

How does the laboratory immunologic assessment of Waldenstrom's Primary Macroglobulinemia differ from other monoclonal gammopathies? - Frequently an increase in IgG, possibly an M spike on serum protein electrophoresis. - Overproduction of IgM antibodies. - Only kappa or lambda monoclonal light chains or Bence-Jones protein seen on serum protein electrophoresis. - Characterized by the presence of monoclonal proteins composed of the heavy chain portion of the immunoglobulin molecule.

- Overproduction of IgM antibodies. Waldenstrom's macroglobulinemia (WM) is a B-cell disorder characterized by the infiltration of lymphoplasmacytic cells into bone marrow and the presence of an IgM (19S)monoclonal gammopathy. The basic abnormality in this macroglobulinemia is the uncontrolled proliferation of B lymphocytes and plasma cells. As a result, there is a heavy accumulation of monoclonal IgM in the circulating plasma and plasmacytoid lymphocytes in the bone marrow. In many cases, WM is associated with mixed cryoglobulinemia, which reflects the binding of IgG and IgA antiidiotypic antibodies to the mutant IgM. In a small number of patients, dysplastic tumor cells secrete 7S IgM monomers, ...chains, or other monoclonal immunoglobulins or fragments. But the major IgM production indicates that the immunoglobulin (gene) lesion sometimes degenerates and codes for more than one M component. Serum electrophoresis usually demonstrates the overproduction of IgM antibodies. Diagnosis of WM is made by the demonstration of a homogeneous M component composed of monoclonal IgM. Blood samples are described as having hyperviscosity. In addition, cryoglobulins can be detected in the patient's serum. The characteristics of an increase in IgG with possibly an M spike on serum protein electrophoresis is diagnostic of Multiple Myeloma (MM). MM is the most common form of dysproteinemia. MM is the prototypical monoclonal gammopathy. IgG myeloma is the most common form of MM. In light Chain Disease (LCD), only kappa or lambda monoclonal light chains or Bence-Jones proteins are seen on serum protein electrophoresis. LCD represents about 10% to 15% of monoclonal gammopathies. The presence of monoclonal proteins composed of the heavy chain portion of the immunoglobulin molecule is characteristic of Heavy Chain Disease. This monoclonal gammopathy can display alpha, gamma or Mu forms of the disease.

Components of the second line of defense in the human body are: - Intact skin; unbroken mucosal membrane surfaces - Phagocytic cells; complement - Dendritic cells; specific antibodies - Lymphocytes; complement

- Phagocytic cells; complement Phagocytic cells e.g., neutrophils, macrophages, dendritic cells, are an important component of natural immunity, the second line of body defense. The elements of natural resistance include phagocytic cells, complement, and the acute inflammatory reaction. If a microorganism penetrates the skin or mucosal membranes, the second line of cellular and humoral defense mechanisms becomes operational. Complement proteins are the major humoral fluid component of natural immunity in the second line of body defense. Other substances of the humoral component include lysozymes and interferon. Interferon is produced rapidly by many cells in response to viral infection; it blocks the replication of the virus in other cells. Intact skin and unbroken mucosal membrane surfaces are components of the first line of defense in the human body. These surfaces are essential in forming a physical barrier to many microorganisms because this is where foreign materials usually first contact the host. Fluids, such as tears and saliva, are components of the first line of defense, as are secretions, such as mucus. Dendritic cells are a component of the second line of defense in a human being; however, specific antibodies are formed to antigenic stimulation and become available to protect the body against foreign substances. Lymphocytes are the major cellular component of acquired immunity, and the major humoral component is the antibody. Both of these components participate in the third line of defense-adaptive immunity. Complement is the major humoral fluid component of natural immunity in the second line of body defense. Phagocytic cells e.g., neutrophils, macrophages, dendritic cells, are an important component of natural immunity, the second line of body defense. The elements of natural resistance include phagocytic cells, complement, and the acute inflammatory reaction. If a microorganism penetrates the skin or mucosal membranes, a second line of cellular and humoral defense mechanisms becomes operational. Complement proteins are the major humoral fluid component of natural immunity in the second line of body defense. Other substances of the humoral component include lysozymes and interferon. Interferon is produced rapidly by many cells in response to viral infection; it blocks the replication of virus in other cells.

Which components characterize the second line of human body defense against microbial pathogens? - Unbroken skin and antibodies - Tears and saliva - Phagocytic neutrophils and macrophages - Unbroken mucous membranes and antibodies

- Phagocytic neutrophils and macrophages Phagocytic neutrophils and macrophages are components of the second line of defense: Natural Immunity. Natural (innate or inborn) resistance is one of the two ways the body resists infection if microorganisms have penetrated the first line of defense. Natural immunity is characterized as a nonspecific mechanism. This second line of defense consists of particular cells (neutrophils, tissue basophils, macrophages) and soluble substances in the blood (complement, lysozyme, interferon). Neutrophils, monocytes, and macrophages can engulf invading foreign material such as bacteria. In addition to the cellular components, complement proteins are the major fluid component of natural immunity. Lysozymes and interferon are sometimes referred to as natural antibiotics. Interferon is a family of proteins produced rapidly by many cells in response to viral infection; it blocks the replication of viruses in cells. Unbroken skin is a component of the first line of defense. A component of the first line of defense or first barrier to infection is unbroken skin and mucosal membrane surfaces. These surfaces are extremely important because they form a physical barrier to many microorganisms. The constant motion of the ciliated epithelial cells provides additional protection to the respiratory tract. Tears, saliva, and other body secretions are a component of the first line of defense against microbial invasion. Other beneficial secretions include mucus, earwax, lactic acid in sweat, and stomach acid. Unbroken mucous membranes are another component of the first line of defense. The stickiness of mucous on membranes attracting dust and airborne microorganisms.

What has happened in an antibody titer, if tubes #5-7 show a stronger reaction than tubes #1-4? - Poor technique - Postzone reaction - Prozone reaction - Zone of Equivalence reaction

- Prozone reaction Prozone is a phenomenon that occurs in a serological reaction when the concentration of antibodies is so high that the optimum concentration for maximal reaction with antigen is exceeded. Reactions in the prozone region may show partial or total inhibition. In this case, there is a partial inhibition in tubes 1-4 where the antibody is in higher concentrations causing the prozone effect. In tubes 5-7, the antibody concentration is weaker, there is no prozone effect, and a stronger visible reaction will occur in these tubes. Poor technique can cause laboratory errors, including prozone. If too much serum-containing antibodies is added to the serial dilution, the prozone reaction in tubes can be significantly increased and could exceed the dilution of the last tube in a serial dilution. Postzone phenomenon occurs when excess antigen is present and lattice formation cannot occur between antigens and antibodies. This causes a false negative reaction. Zone of equivalence is when both antigen and antibody are present in optimal proportions. In equivalence, an adequate concentration of antibodies can bind to an adequate concentration of antigens which results in a lattice formation.

A false-positive result can be observed in a rheumatoid factor latex agglutination procedure reaction due to: - Poor specimen quality - Antigen excess - Excessive complement levels - Juvenile idiopathic arthritis

- Poor specimen quality Technical false-positive results may be obtained if a patient's serum is lipemic, hemolyzed, or heavily contaminated with bacteria or if the test result is read after the specified time. Serum is usually the specimen used for the rapid latex agglutination test for RA . If the test cannot be performed immediately, the specimen should be refrigerated. If the test cannot be performed within 72 hours, the specimen should be frozen. Frozen serum should be thawed rapidly at 37 °C before testing. Before the test is done, the specimen should be at room temperature. All reagents used for the rapid slide RF tests must also be at room temperature. It is always important to follow carefully all instructions provided with the testing product. RF belongs to a larger family of antiglobulins, usually defined as antibodies with specificity for antigen determinants on the Fc fragment of human or certain animal IgG. RFs have been associated with three major immunoglobulin classes: IgM, IgG, and IgA. The tests for RF are based on the reaction between antibodies in the patient's serum (RF) and an antigen derived from gamma globulin. Generally, all tests are designed to detect antibodies to immunoglobulins. A latex-coated suspension with albumin and chemically bonded with denatured human gamma globulin serves as the antigen in one common test for RF. If RF is present in the serum, macroscopic agglutination will be visible when the latex reagent is mixed with serum. Latex agglutination procedures have a 95% correlation with a clinical diagnosis of probable or definite RA Complement levels are generally normal in patients with rheumatoid arthritis, except for patients with vasculitis. Approximately 20% of children are positive for RF. So-called hidden RF can be detected in 65% of children with negative latex fixation test results.

An indirect latex agglutination assay was used to test for C-reactive protein in a patient sample. The results of the serial dilution are provided in the image. Choose the correct reportable result (titer): - Positive 1:3 - Positive 1:6 - Positive 1:12 - Positive 1:24

- Positive 1:12 The presence of C-reactive protein (CRP) in a patient serum is an indicator of inflammation. An indirect latex agglutination assay can be used to detect CRP levels in a patients serum. Patient serum that is positive for C-reactive proteins require a serial dilution to determine the titer (concentration) of the protein in the serum. The titer is the last tube showing a positive reaction or the lowest dilution at which a particular reaction takes place.

Hyperacute rejection of a transplanted organ is caused by: - Pre-formed humoral antibodies in a patient - Patient sensitization to donor antigens - Development of allogeneic reaction to donor antigens - Disturbance of host-graft tolerance

- Pre-formed humoral antibodies in a patient The presence of pre-formed humoral antibodies in a patient reacting with donor tissue cellular antigens is the entire cause of hyperacute rejection. The preformed antibodies are usually anti-A or anti-B related antibodies to the ABO system or antibodies to class I MHC antigens (hypersensitivity type II). Previous patient sensitization to donor antigens is a T cell-mediated cause of accelerated rejection of graft rejection in kidney grafts. It is comparable to the second-set rejection phenomenon observed in animal models of graft rejection. The development of an allogeneic reaction to donor antigens is the cause of acute rejection. This type of rejection can result after the first exposure to antigens. Although the early process of rejection, equivalent to a first-set allograft rejection in experimental animals, is mediated by T cells, later rejection may involve antibodies and complement, possibly antibody cell-mediated cytotoxicity). Disturbance of host-graft tolerance, chronic graft rejection, is a cell-mediated process that develops later than 3 months after transplantation. Chronic rejection occurs in most graft recipients. The process produces a slow but continual loss of organ function.

All of the following characteristics describe T lymphocytes EXCEPT? - CD4 & CD 8 positive - Production of surface immunoglobulins - Production of cytokines and chemokines - Recruitment of inflammatory cells to site of inflammation or infection

- Production of surface immunoglobulins T and B lymphocytes cannot be distinguished by their peripheral blood smear morphology. Only mature B lymphocytes produce surface immunoglobulins, IgM and IgD, T lymphocytes do not. T lymphocytes characteristically exhibit CD4 and CD8 cell surface markers on flow cytometry. T lymphocytes also recruit neutrophils, eosinophils, and basophils to inflammation or infection sites. T lymphocytes help integrate immune responses by producing cytokines and chemokines. T lymphocytes also assist B lymphocytes to make antibodies.

Which of the following types of molecules is most likely to be antigenic/immunogenic? - Nucleic acids - Carbohydrates - Lipids - Proteins

- Proteins Proteins are complex molecules with a high molecular weight and are more antigenic than the other types of molecules. Carbohydrates are the second most antigenic molecules. Lipids are the third antigenic molecules from this list. Nucleic acids are not generally antigenic.

Which one of the following are normal genes that induce DNA synthesis, promote cell division, and inhibit cell death? - Tumor suppressor genes - Proto-oncogenes - Oncogenes - Mismatch repair genes

- Proto-oncogenes Proto-oncogenes are normal genes that promote cell growth and division. Mutations in proto-oncogenes can convert them into oncogenes, which are abnormal genes that cause the continuous cell division and uncontrolled cell growth characteristic of cancer. Tumor suppressor genes are normal genes that inhibit cell division. Mismatch repair genes are normal genes that play a role in the repair of errors that can occur during DNA replication.

The primary purpose of neutrophil granules is to: - Facilitate nuclear maturation. - Help distinguish neutrophils from lymphocytes. - Prepare cells for removal from circulation. - Provide microbicidal action.

- Provide microbicidal action. Neutrophils are a key component of the innate defense system. Neutrophil granules contain enzymes and other proteins that break down substrates, kill ingested bacteria, and secrete their contents during an inflammatory response. The granules do not have a role in nuclear maturation or in preparing cells for removal from circulation. While granules are a feature that helps distinguish neutrophils from lymphocytes, this is not their primary purpose.

Which testing method is appropriate for identifying specific allergens? - Complement fixation - C-reactive proteins - Radioimmunoassay (RIA) - Radioallergosorbent tests (RAST)

- Radioallergosorbent tests (RAST) Radioallergosorbent tests (RAST) is a procedure that detects the presence of IgE (and IgG) antibodies to allergens; a method used to measure antigen-specific IgE by means of a noncompetitive solid-phase immunoassay. Complement fixation is a traditional procedure that detects the presence of a specific antigen-antibody reaction by causing in vitro activation of complement. If complement is not fixed, lysis of the preantibody-coated reagent erythrocytes (RBCs) occurs. The acute-phase protein, CRP, is used clinically for monitoring infection, autoimmune disorders, and, more recently, healing after myocardial infarction. Radioimmunoassay (RIA) is an older and less frequently used laboratory technique that uses radioactive substances to evaluate immunoglobulins. Traditional RIA is done with specific antibodies in a liquid solution. Solid-phase RIA uses antibody-bound to a solid support, e.g. glass beads.

Vaccines can be divided into the following non-experimental types with the exception of: - Live, attenuated - Inactivated - Toxoid - Recombinant vector

- Recombinant vector Recombinant vector vaccines are experimental vaccines similar to DNA vaccines, but they use an attenuated virus or bacterium to introduce microbial DNA to cells of the human body. Vector refers to the virus or bacterium used as the carrier. Researchers are working on recombinant vector vaccines for HIV, rabies, and measles. Live attenuated vaccines contain a version of the living microorganisms that have been weakened in the laboratory to prevent the organism from causing disease. A live attenuated vaccine is the closest thing to exposure to a natural infection. Inactivated vaccines are manufactured by killing an infectious microbe with chemicals, heat, or radiation. This type of vaccine is more stable and safer than live vaccines. The disadvantage of inactivated vaccines is that they stimulate a weaker immune system response than live vaccines. Usually, a weaker response necessitates additional doses or booster shots to maintain immunity, e.g., influenza vaccination. Toxoid vaccines are used when a bacterial toxin is the main cause of illness. Toxins can be inactivated. Such "detoxified" toxins called toxoids are safe for use as vaccines. A toxoid vaccine containing a harmless toxoid stimulates the immune system to produce antibodies that react to and block the toxin. Vaccines against diptheria and tetanus are examples of toxoid vaccines.

Given the following results, what is the immune status of the patient? HBsAg: negative HBeAg: negative Anti-HBc: positive Anti-HBs: positive - Acute infection - Chronic infection - Recovery - Immunization

- Recovery If the hepatitis B antigens are no longer present (HbsAg and HbeAg), there is no longer virus present. The fact that the Anti-HBs and Anti-HBc are BOTH positive, indicates that there is a recovery process occurring after infection with hepatitis B virus. It is important to note that Anti-HBs also develops in a person who has been successfully vaccinated against hepatitis B. Since this patient displayed a positive Anti-HBc result, immunization could not be the correct answer.

The prozone effect can be described by all of the following EXCEPT: - Results in a false negative reaction - The result of antibody excess - Dilution of antibody can help prevent its occurrence - Results in a false positive reaction

- Results in a false positive reaction Prozone is the result of antibody excess--where the concentration of antibody exceeds the concentration of antigen; it appears as a false negative, which can become positive as the patient's serum is diluted. It does not yeild a false positive reaction.

What molecular technique is appropriate for HIV-1 genotyping? - Reverse Transcriptase Polymerase Chain Reaction - Multiplex Polymerase Chain Reaction - Real-Time Polymerase Chain Reaction - Strand Displacement Amplification

- Reverse Transcriptase Polymerase Chain Reaction Reverse Transcription Polymerase Chain Reaction (RT-PCR)/nucleic acid sequencing is the procedure that can be modified to include the conversion of RNA to DNA using reverse transcriptase in the initial steps. RT-PCR is useful in the identification of RNA viral agents, such as human immunodeficiency virus (HIV) and, in particular, HIV-1 genotyping. Multiplex Polymerase Chain Reaction uses numerous primers in a single reaction tube to amplify nucleic acid fragments from different targets. Specific nucleic acid amplification should occur if the appropriate target DNA is present in the sample test. Real-Time Polymerase Chain Reaction uses fluorescence-resonance energy transfer to quantitate specific DNA sequences of interest and to identify point mutations. Strand Displacement Amplification is a method that amplifies target nucleic acid without the use of a thermocycler. A double-stranded DNA fragment is created and becomes the target for exponential amplification.

A patient had a differential diagnosed of Systemic Lupus Erythrematosus (SLE).Laboratory Results: ANA = positive (homogeneous pattern), titer 1:320, RA=positive, Complement = decreased. All of the following specific laboratory tests meet the criteria for a definitive diagnosis of SLE, EXCEPT? - A positive antinuclear antibody (ANA) - Smith (Sm) antibodies - Double-stranded DNA (dsDNA) antibodies - Ribonucleic protein (RNP) antibodies

- Ribonucleic protein (RNP) antibodies Ribonucleic protein (RNP) antibodies are not specific for Systemic Lupus Erythematosus (SLE). In addition, Anti-Sjögren's syndrome antigen A (SSA, or Ro) and anti-Sjögren syndrome antigen B (SSB, or La) antibodies and histone antibodies are not specific for SLE. Anti-ribosomal P (anti-P) is associated with neurolupus but not particularly useful in management or diagnosis of neuropsychiatric lupus. Chromatin antibodies detection is of primary use in the diagnosis of drug-induced lupus not SLE. The initial laboratory results demonstrated a positive ANA test, or anti-nuclear antibody, which is a screening test for Lupus erythrematosus; an RA test, or rheumatoid factor, screening assay for the presence of an antibody linked with rheumatoid arthritis and other conditions, such as lupus erythematosus. Renal disease in patients with Systemic Lupus Erythematosus is indicated by an assessment of the levels of C3 and C4. In this case, there was a decreased level. A decrease in complement proteins indicates that the classic complement pathway may have been activated resulting in immune complexes, a clinically significant indication of tissue damage, particularly renal disease. Patients with SLE are characterized by the presence of antibodies to multiple antigens but some of these antibodies are not exclusive to SLE. An extractable nuclear antibody, Smith (Sm) antibody, is highly specific for SLE, but occurs in only 20-30 or35% of cases. Double-stranded DNA (dsDNA) antibodies (titer >1:10) detected by immunofluorescence assay (IFA) is seen in up to 50-60% of patients with Systemic Lupus Erythematosus (SLE). These antibodies indicate an active disease.

Which of the following would be considered most significant as it relates to serological testing: - Presence of an antibody titer is generally diagnostic - Rise of antibody titers is diagnostic - Concentration of antibody is diagnostic - Cross reactivity is not significant

- Rise of antibody titers is diagnostic Serological diagnosis of active or recent infection generally requires the demonstration of IgM antibody, or the demonstration of a fourfold rise in the titer of specific IgG antibody.

Which of the following blood smear observations would support the diagnosis of Multiple Myeloma if a patient demonstrated plasma cells in his bone marrow and had an elevated serum IgG? - Anisocytosis - Target cells - Microcytic RBC's - Rouleaux formation

- Rouleaux formation Plasma cells produce antibodies (immunoglobulins). Multiple myeloma is a neoplastic condition of the plasma cell. Plasma cells in the bone marrow with an increase in IgG is suggestive of multiple myeloma; which is strongly associated with rouleaux formation due to the increased immunoglobulins present. Rouleaux is the sticking together of RBC's, resembling a stack of coins. This happens because of the increase in immunoglobulin production, given immunoglobulins are large proteins. This excessive plasma protein creates a 'sticky' environment for the RBC's. Anisocytosis, which refers to an increased variation in the size of RBC's, is not a distinguishing characteristic of multiple myeloma. Target cells, also known as codocytes, are not a key laboratory finding in multiple myeloma. Microcytic RBC's, which are represented by a low MCV, are not a distinguishing characteristic of multiple myeloma.

Which one of the following statements is FALSE? - Fever can have a direct effect on the growth or death of pathogenic microorganisms. - Low pH of stomach, skin, and vagina can inhibit microbial growth. - Secretory cells of the innate immune system are antigen specific. - Oxygen tension can result in the death of microorganisms due to oxidation.

- Secretory cells of the innate immune system are antigen specific. The innate immunity system is inherent and nonspecific, meaning that all pathogens are attacked similarly and are not antigen-specific. Fever will have a direct effect on pathogenic microorganisms and can inhibit their growth or result in their death. pH has a direct effect on many pathogens limiting their survival or ability to reproduce. Oxygen tension has a direct effect on many pathogens results in death due to oxidation.

A 2-month old infant presented with history of chronic diarrhea and failure to thrive. The child's mother also revealed that the baby has suffered from thrush (Candida infections) since birth. Preliminary findings showed lymphopenia (<2,000), hypogammaglobulinemia, and physical findings showed a small thymus, no tonsils or lymph nodes. Which of the following immune deficiencies DOES the patient present? - T-cell activation deficiency - MCH deficiency - Deficiency in immunoglobulin production - Severe combined immunodeficiency syndrome

- Severe combined immunodeficiency syndrome Severe combined immunodeficiency syndrome, or SCID is a very serious human immunodeficiency disorder. It is actually a group of congenital disorders in which both the humoral and cell-mediated portions of a patient's immune system are dysfunctional. Children with SCID are vulnerable to recurrent severe infections, retarded growth, and early death.

Which method remains the "gold standard" for ANA detection? - Radioimmunoassay (RIA) - Ouchterlony immunodiffusion - Enzyme Immunoassay (ELISA) - Slide-based immunofluorescent assay (IFA)

- Slide-based immunofluorescent assay (IFA) The slide-based immunofluorescent assay (IFA) using HEp-2 cells is considered to be the gold standard for antinuclear antibody (ANA) testing. This is because the IFA is highly sensitive, detecting a wide range of antibodies to nuclear antigens present in their natural form and location in the cells. RIA (radioimmunoassay) is not a method used for ANA testing, due to the hazards of working with and disposing of the required radioactive labels. Ouchterlony immunodiffusion is a highly specific, but insensitive technique that has been used to identify antibodies to specific extractable nuclear antigens (ENA). Solid phase assays such as microbead and ELISA assays are automated but have a lower sensitivity than IFA, resulting in a higher number of false negative results.

Identify the anti-nuclear antibody (ANA) pattern in this microscopic image. - Homogeneous - Speckled - Anticentromere antibody - Anti-Ro (SS-A) (alcohol fixation)

- Speckled The speckled pattern occurs in the presence of antibodies to any extractable nuclear antigen devoid of DNA or histone. The antibody is detected against the saline extractable nuclear antigens, anti-RNPand anti-Sm. A grainy pattern with numerous round dots of nuclear fluorescence, without staining of the nucleoli, is seen in this pattern type. Antibodies to anti-RNP have been found in patients with a wide variety of rheumatic disorders, including SLE. Antibodies to Sm antigen have been shown to be highly specific for patients with systemic lupus erythematosus (SLE). This is an example of a cell cycle-dependent speckled ANA pattern called anti-proliferating cell nuclear antigen (PCNA). With this pattern, the antigen that the antibodies are directed against is only expressed during a limited portion of the cell's growth cycle. During other parts of the growth cycle, the antigen is not expressed. This creates a pattern where only 30-50% of the cells stain positive. The speckled staining within these positive cells varies between coarse speckled (a) and smooth speckled (b). Cells not expressing the antigen are negative (c). A homogeneous pattern characterizes anti-DNA nucleoprotein antibodies (i.e., antibodies to nDNA, dsDNA, ssDNA, DNP, or histones). The antinuclear antibody (ANA) test pattern is characterized by smooth staining in the nuclei of the interphase cells and smooth staining in the chromosomal areas of the metaphase mitotic cells . The nucleoli may or may not stain. Although vacuoles may be seen, the whole nucleus fluoresces evenly. In order for the ANA to be positive, there must be a clearly discernible pattern in the nuclei of the interphase cells. Metaphase mitotic cells are used to assist in the identification of the ANA pattern. This pattern is typically seen in rheumatoid disorders. High titers of homogeneous ANA suggest Systemic Lupus Erythematosus (SLE); low titers may be found in SLE, Rheumatoid arthritis, Sjorgen's syndrome, and mixed connective tissue disease. Anticentromere antibody reacts with centromeric chromatin of metaphase and interphase cells. The particular pattern on tissue culture cells is discrete and speckled. This antibody is found infrequently in the serum of patients with systemic lupus erythematosus (SLE). Anti-Ro (SS-A) antibody is included in the nonhistone protein (NhPs) and NhP-RNA complexes in systemic rheumatic disease. The incidence of the antibody is 50% in cases of SLE. Detection of antibodies to SS-A/Ro varies according to the fixation method. Alcohol diminishes or destroys the SS-A/Ro speckled ANA pattern, leading to a negative ANA.

There are two patterns present in this microscopic field from an antinuclear antibody ANA test. The test is viewed using fluorescent microscopy. One pattern can be seen in the interphase cells (a) and the area outside of the chromosomal area of the mitotic cells (b). The other pattern is recognizable in the chromosomal area of the metaphase mitotic cells (c). What are these two patterns? - Homogeneous and nucleolar - Speckled and homogeneous - Speckled and centromere - Centromere and nucleolar

- Speckled and homogeneous This is an example of a mix of homogeneous and speckled ANA patterns. In this sample, notice that the speckled ANA is the dominant pattern in the interphase cells (a) and some speckling is present in the area outside of the chromosomal area of the mitotic cells (b). Also notice the smooth staining of the chromosomal area of the metaphase mitotic cells (c). This represents the presence of a homogeneous ANA pattern. In addition, there is no staining of the nucleoli within the nuclei of the interphase cells, and absence of centromere staining, which would appear as numerous tiny discrete speckles in both the nondividing and dividing cells.

Patients with antibody to the following antigen are immune to Hepatitis B: - Core antigen - Surface antigen - e antigen - Delta antigen

- Surface antigen Patients who have antibodies directed against the hepatitis B surface antigen, or anti-HBs, have an immunity to hepatitis B. This is the principle behind hepatitis B vaccinations, as proteins associated with the hepatitis B surface antigen are administered to an individual, who then produces an immune response against the surface antigen. The antibodies produced through this process allow for the immunization against the hepatitis B virus. Titers with antibodies against the hepatitis B core antigen increase during the window period and will remain increased along with the hepatitis B surface antigen in chronic infections. Testing this antibody alone cannot differentiate a patient who is entering convalescence from one who has a chronic infection. Testing patients for antibodies against the hepatitis B e antigen is not routinely performed as not all strains of hepatitis B produce the e antigen, so the patient would not synthesize the corresponding antibody. Patients with antibodies to the Delta antigen have a concomitant infection to hepatitis D. As this is not common in the United States, it is not routinely tested.

T lymphocytes are characterized by all of the following functions EXCEPT which? - Secrete cytokines - Synthesize antibody - Comprise majority of cells in blood lymphocyte pool - Help regulate immune response

- Synthesize antibody T lymphocytes perform all of the listed functions EXCEPT synthesizing antibodies. B lymphocytes and plasma cell synthesize antibodies (immunoglobulins). T lymphocytes secrete cytokines, comprise the majority of cells in the lymphocyte pool, and help regulate immune response.

The VDRL and RPR are used to provide presumptive identification of which infection? - Gonorrhea - Syphilis - Chlamydia trachomatis - Haemophilus ducreyi

- Syphilis The VDRL and RPR are used to provide presumptive identification of Treponema pallidum, the causative agent of syphilis. T. pallidum is identified differently than other common pathogens and requires special serological testing for confirmation. Neisseria gonorrhea, the causative agent of gonorrhea, is best identified using nucleic acid-based methods. Chlamydia trachomatis can be diagnosed using culture, but nucleic acid amplification is increasingly being used. Haemophilus ducreyi is best identified by using molecular methods.

Which autoimmune disorder is characterized by a homogenous pattern in an immunofluorescence (IF) microscopy test for anti-nuclear antibodies (ANAs)? - Sjogren's syndrome - CREST syndrome - Systemic Lupus Erythematosus (SLE) - Scleroderma

- Systemic Lupus Erythematosus (SLE) A homogeneous ANA pattern is seen in more than 95% of patients suffering from Systemic Lupus Erythematosus (SLE). This pattern characterizes anti-DNA nucleoprotein antibodies, i.e. antibodies to nDNA, dsDNA. In addition to a homogeneous ANA pattern related to SLE, a peripheral or rim pattern of nDNA can be seen in active SLE, and a speckled pattern related to the presence of anti-Smith antibody can be observed. Because the detection of ANAs is not exclusively diagnostic for SLE, their presence cannot confirm the disorder. However, the absence of ANAs can be used to help rule out SLE. Sjogren's syndrome can be associated with a homogeneous ANA pattern, a peripheral or rim ANA pattern, a speckled ANA pattern, or a nucleolar ANA pattern. CREST syndrome is characterized by a discrete, speckled ANA pattern with antibody specificities to the centromere, DNA, RNA, and ENA. A centromere pattern is found infrequently in patients with SLE and other disorders. Scleroderma is characterized by a nucleolar pattern. Although Sjogren's syndrome and undiagnosed illnesses manifesting Raynaud's phenomenon can also demonstrate the presence of the 4-6s RNP antibody.

Jane Doe is a 30-year-old female who felt tired for several months, had pain in the joints of her fingers, and recently developed a dermatitis following exposure to the sun. The following test results were obtained on a blood sample drawn during the initial evaluation: Total Protein = 8.4 gm/dL (N = 6.0-8.0 gm/dL) ANA >1:2560; speckled pattern CRP = positive C3 = 40 mg/dL (N = 80-180 mg/dL) C4 = 5 mg/dL (N = 15-45 mg/dL) Based on the clinical and laboratory findings, what disease should be suspected? - Rheumatoid arthritis - Systemic Lupus Erythematosus (SLE) - Sjogren's syndrome - Scleroderma

- Systemic Lupus Erythematosus (SLE) The combination of laboratory results, as well as the presence of joint pain and dermatitis in a woman of child-bearing age, support a diagnosis of systemic lupus erythematosus (SLE). Anti-nuclear antibodies (ANAs) are found in over 95% of patients with SLE. A speckled pattern is commonly found in patients with SLE, indicating the presence of antibodies to a variety of nonhistone, small ribonucleoprotein (RNP) particles. While a speckled ANA pattern can be associated with systemic autoimmune rheumatic diseases other than SLE, such as rheumatoid arthritis, Sjogren's syndrome, and scleroderma, the possibility of SLE is increased in patients with a high titer, as seen in this case. A high CRP level indicates that inflammation is occurring, as in SLE, for example, but does not indicate the location or cause of the inflammation. Decreased complement levels also are associated with autoimmune diseases. Both C3 and C4 levels are typically depressed in SLE. In rheumatoid arthritis, serum complement levels are usually normal or increased due to acute-phase reactivity.

Which immune elements are involved in a POSITIVE TB skin test? - IgE - T cells and macrophages - Nk cells and IgG antibodies - B cells and IgM antibodies

- T cells and macrophages A positive tuberculosis (TB) skin test is an example of a Type IV Cell-Mediated delayed hypersensitivity reaction. Cell-mediated immunity is moderated by the link between T lymphocytes and phagocytic cells. This reaction involves antigen sensitized T lymphocytes or particles that remain phagocytized in a macrophage and are encountered by previously activated T lymphocytes for a second or subsequent time. T lymphocytes respond directly, or by the release of lymphokines, to exhibit a contact dermatitis reaction (redness and swelling of the skin around the point of contact). IgE is associated with Type I Hypersensitivity reactions. Type I hypersensitivity reactions can range from life-threatening anaphylactic reactions to milder manifestations associated with food allergies. Immediate hypersensitivity allergic reactions are caused by molecules released by mast cells when an allergen interacts with membrane-bound IgE. Type II Hypersensitivity reactions are initiated by the interaction between antibodies, except IgE and antigen. Antibody-coated cells are lysed by effector cells, such as NK cells and macrophages. NK lymphocytes lack conventional antigen receptors for T or B lymphocytes. NK cells synthesize a number of cytokines involved in the modulation of immune responses. NK cells destroy target cells through an extracellular non-phagocyte mechanism referred to as a cytotoxic reaction. Type II Cytotoxic Hypersensitivity reactions are characterized by the interaction of IgG or IgM antibodies to cell-bound antigens. This binding of an antigen and antibody can result in activation of complement and destruction of the cell (cytolysis) to which antigen is bound. Erythrocytes, leukocytes, and platelets can be lysed by this process. The association of B-type lymphocytes with this process is that after an antigenic challenge, B lymphocytes/plasma cells synthesize antibodies.

Contact dermatitis is mediated by: - B lymphocytes - Mast cells - Polymorphonuclear cells - T lymphocytes

- T lymphocytes Contact dermatitis is an example of a cell-mediated (type IV) hypersensitivity reaction that involves macrophages and T lymphocytes. When an antigen comes in contact with the skin, the antigen is processed by cells in the epidermis and comes in contact with T lymphocytes. T lymphocytes recognize the antigen as foreign and circulate through the bloodstream back to the epidermis. There, they release cytokines that produce an inflammatory response, causing a characteristic rash in the skin called contact dermatitis. B lymphocytes produce antibodies, and these are not involved in contact dermatitis. Mast cells are a key component of Type I hypersensitivity reactions, not cell-mediated hypersensitivity. Polymorphonuclear cells are recruited to the sites where immune complexes have formed in Type III hypersensitivity reactions.

What is the primary target of HIV (human immunodeficiency virus)? - Heart - Liver - Lungs - T-helper cells

- T-helper cells T-helper cells is the correct response. The targets of the HIV virus are the CD4+ T cells (T-helper cells), macrophages, and monocytes. As the virus replicates patients will eventually suffer from a decrease of the T-helper cells, which are critical to the host's immune response. Patients suffering from HIV infections suffer a decreasing functional CD4+ T cell population as the disease progresses, which leads to the acquired immune deficiency syndrome (AIDS). The heart, liver, and lungs do not possess the CD4 receptor to which the HIV virus must attach in order to enter a cell for replication.

The purified protein derivative (PPD) test is also known as: - Targeted tuberculin testing - RPR - QuantiFERON® assay - SPOT TB® assay

- Targeted tuberculin testing The purified protein derivative skin test is also known as a targeted tuberculin testing. This form of skin testing for Mycobacterium tuberculosis. It is performed by injecting 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm. The rapid plasma reagin test (RPR) is not a skin test. It is a serologic test for venereal disease (syphilis). QuantiFERON® assay is not a skin test. It is an interferon-gamma release assay (IGRA) performed in the laboratory. SPOT TB® assay is not a skin test. It is an interferon-gamma release assay (IGRA) performed in the laboratory.

You are performing a manual antibody titer in a clinical laboratory. You have made serial dilutions of a patient's plasma sample and you are looking for anti-streptolysin O antibodies. The first tube contains pure patient plasma. The second tube contains a 1:2 dilution of the first tube. The third tube contains a 1:2 dilution of the second tube and so on. The patient's antibodies no longer give visible reaction in tube 5, indicating their titer is tube 4 (or the last tube where there is a positive result). What is the concentration of antibodies in tube 4 compared to the concentration in tube 1? - The concentration of antibodies in tube 4 is the same as the concentration of antibodies in tube 1. - The concentration of antibodies in tube 4 is about 1/4 the concentration of antibodies in tube 1. - The concentration of antibodies in tube 4 is 1/8 the concentration of antibodies in tube 1. - The concentration of antibodies in tube 4 is 4 times the concentration of antibodies in tube 1.

- The concentration of antibodies in tube 4 is 1/8 the concentration of antibodies in tube 1. The correct response is the third option: The concentration of antibodies in tube 4 is about 1/8 the concentration of antibodies in tube 1.If a serial dilution is made where each sample tube contains a 1:2 dilution based upon the sample before it is in the series, then the pattern for dilution is 1:1, 1:2, 1:4, 1:8, 1:16 and so on. The dilution factor for each tube is multiplied by a factor of 2 as it proceeds through a series. In the example above, the first tube would contain only plasma. The second tube would be a 1:2 dilution, the third tube would be a 1:4 dilution and the fourth tube would contain a 1:8 dilution. Therefore, the concentration of antibodies in tube 4 is 1/8 of the concentration found in the first tube (pure patient plasma).

Koch's postulates include all of the following EXCEPT for which statement? - This microorganism can be isolated from specimens associated with the given disease. - Inoculation of the isolate into a susceptible experimental animal will produce the disease. - The organism can subsequently be recovered from an experimentally infected animal. - The isolated organism, when injected into a human host, will produce the disease.

- The isolated organism, when injected into a human host, will produce the disease. Koch's postulates did NOT include the following statement: The isolated organism, when injected into a human host, will produce the disease.

Avidity is best described by which of the following statements? - The strength with which red cells agglutinate - The strength with which multivalent antigens and antibodies bind - The strength with which univalent antigens and antibodies bind - The speed with which an antigen-antibody reaction occurs

- The strength with which multivalent antigens and antibodies bind The correct answer is the strength with which multivalent antigens and antibodies bind. The term avidity refers to the total strength of the attraction between an antibody and a multivalent antigen. The reaction between an IgM molecule (which has 10 antigen binding sites), and a multivalent antigen is therefore much stronger than that of an IgG antibody (which has only 2 antigen binding sites). The term affinity refers to the strength of attraction between a single antigenic determinant and a corresponding antigen binding site.

All of the following would be considered a part of the body's cellular immune system EXCEPT? - Macrophages - Mast cells - Neutrophils - Thrombocytes

- Thrombocytes Thrombocytes, or platelets, are of course involved with hemostasis, not immunity. Body defense systems include cellular and molecular components. The cellular component includes phagocytic cells, inflammatory mediators, and natural killer cells. The phagocytic cells include neutrophils, monocytes, and macrophages. Cells that release inflammatory mediators include basophils, mast cells, and eosinophils. The molecular component includes complement, acute phase proteins, and cytokines.

Which of the following autoantibodies are found in a patient with Graves disease but not typically seen in Hashimotos thyroiditis? - Thyroid-stimulating hormone receptor antibodies (TRAbs) - Antithyroid peroxidase (TPO) - Islet cell antibodies - Antitransglutaminase (tTG)

- Thyroid-stimulating hormone receptor antibodies (TRAbs) Thyroid-stimulating hormone receptor antibodies (TRAbs) are associated with Graves disease. While Antithyroid peroxidase (TPO) antibodies are associated with Hashimoto's thyroiditis and Graves disease, they are found in about 95% of patients with Hashimoto's and are the best indicator of the disease. Islet cell antibodies are associated with Type 1 diabetes mellitus. Antitransglutaminase (tTG) antibodies are associated with Celiac disease.

Which modified PCR technique or other method of amplification is used to detect Mycobacterium tuberculosis? - Transcription-Mediated Amplification - Reverse Transcriptase PCR - Real-Time PCR - Nucleic Acid Sequence-Based Amplification

- Transcription-Mediated Amplification Transcription-Mediated Amplification (TMA) is an isothermal assay that targets DNA or RNA but generates RNA as its amplified product. TMA is used to detect microorganisms such as Mycobacterium tuberculosis. Reverse Transcriptase PCR Reverse Transcription Polymerase Chain Reaction (RT-PCR)/nucleic acid sequencing is the procedure that can be modified to include the conversion of RNA to DNA using reverse transcriptase in the initial steps. RT-PCR is useful in the identification of RNA viral agents, such as human immunodeficiency virus (HIV) and, in particular, HIV-1 genotyping. Real-Time Polymerase Chain Reaction (Real-Time PCR) uses fluorescence-resonance energy transfer to quantitate specific DNA sequences of interest and to identify point mutations. Nucleic Acid Sequence-Based Amplification is similar to Transcription-Mediated Amplification (TMA), but only RNA is targeted for amplification. Its applications include the detection and quantitation of human immunodeficiency virus (HIV) and detection of cytomegalovirus (CMV).

HLA antibodies are responsible for which of the following transfusion reactions? - Allergic transfusion reactions - Transfusion-associated sepsis - Transfusion-associated circulatory overload - Transfusion-related acute lung injury (TRALI)

- Transfusion-related acute lung injury (TRALI) Antibodies to human leukocyte antigens (HLA) are responsible for transfusion-related acute lung injury (TRALI). The pathogenesis of this transfusion reaction is not fully understood, but there are two accepted mechanisms. The first involves antibodies to human leukocyte antigens or human neutrophil antigens transfused into a recipient. The antibodies bind and activate the recipient's leukocytes. The second mechanism involves a patient undergoing some event that primes their leukocytes. This includes a disease state, infection, or trauma). The patient is then transfused with a product that contains cytokines or anti-leukocyte antibodies, which then activate the already primed leukocytes. Both mechanisms cause leukocytes (especially neutrophils) to aggregate in the lungs. As a result, there is damage to the endothelium, which leads to an increase in pulmonary capillary permeability and noncardiogenic pulmonary edema. Allergic reactions are due to a recipient having an antibody (usually IgE) to a protein in the donor's plasma. They can also be caused by donor antibodies to a protein present in the recipient's plasma. Transfusion-associated sepsis is caused by bacterial contamination of a transfused product. Transfusion-associated circulatory overload is caused by the inability of a patient's circulatory system to handle the additional workload from the transfused product. It occurs when the volume or rate of transfusion is too high.

The lymphocyte subtype that controls autoimmunity in the peripheral blood is: - Treg - TH1 - TH2 - B

- Treg Tregare immunoregulatory CD4+T lymphocytes that control autoimmunity in the peripheral blood. The primary function of Treg cells was originally defined as the prevention of autoimmune diseases by maintaining self-tolerance. Treg cells that express the transcription factor, Foxp3, and produce IL-10 are required for systemic immunologic tolerance. Treg cells are characterized by constitutive expression of CD25 and are developed primarily in the thymus from positively selected thymocytes with high avidity for self-antigens. The TH1subset of CD4+ effector T lymphocytes secrete interferon (IFN-?) that acts on macrophages to increase phagocytosis and killing of microbes, and on B lymphocytes to stimulate the production of IgG antibodies that opsonize microbes for phagocytosis. But help for antibody production may be provided, not by classical TH1 cells, most of which migrate out of lymphoid organs to sites of infection and inflammation, but by follicular helper T cells that remain in lymphoid organs and produce (IFN-?).The role of IFN-? has been established in mice but not in human beings. The TH2 subset of CD4+ effector T lymphocytes (Helper T type 2) plays a significant role in the regulation of antibody production. This subset secretes IL-4, IL-5, and IL-13. IL-4 and IL-13 act on B cells to stimulate the production of antibodies that bind to mast cells, such as IgE. TH2 cells mediate host defense against extracellular parasites, including helminths. They are important in the induction and persistence of asthma and other allergic inflammatory disorders. TH2 cells produce Il-4, Il-5, IL-9, IL-10, IL-13, IL-25, and amphiregulin, a protein member of the epidermal growth factor (EGF) family. B lymphocytes, B1 and B2, are subsets. B-cell functions include source of natural antibody and major source of IgM; host protection; clearance of apoptotic cells; possible negative selection of self-reactive B cells; and response to stress-induced antigens.

All of the following are associated with immediate hypersensitivity, EXCEPT? - Hay fever - Urticaria (Hives) - Tuberculin reaction - Anaphylactic shock

- Tuberculin reaction Hay fever, urticaria, and anaphylactic shock are associated with immediate hypersensitivity reactions, which generally appear within 30-60 minutes of an antigen challenge. These reactions are due to the binding of IgE antibodies to receptors on mast cells and basophils, triggering them to release vasoactive mediators. The tuberculin skin reaction is a delayed hypersensitivity reaction that is due to the effects of T lymphocytes and cytokines and appears 48-72 hours after antigen exposure.

Nephelometry is based on the principle of: - Turbidity resulting from specific antigen-coated latex particles agglutinated by corresponding antibody - Agglutination resulting from physical attachment of antibody molecules to antigens on an erythrocyte membrane - Agglutination of host antibody to antigenic determinants on a bacterial agent - Precipitation of immune-related proteins in agarose gel

- Turbidity resulting from specific antigen-coated latex particles agglutinated by corresponding antibody The measurement of turbidity resulting from specific antigen-coated latex particles agglutinated by corresponding antibodies is the principle of nephelometry. In nephelometry, the light-scattering properties of antigen-antibody complexes are measured photometrically as macromolecular complexes form. Nephelometry is used in immunology to measure complement components, immune complexes, and the presence of a variety of antibodies. Agglutination resulting from the physical attachment of antibody molecules to antigens on an erythrocyte membrane is called hemagglutination. If a sufficient concentration of antibody is present, antigen-specific erythrocytes are cross-linked and agglutinated. Agglutination of host antibody to antigenic determinants on a bacterial agent is the principle of direct bacterial agglutination. Direct agglutination of whole pathogens can be used to detect antibodies directed against pathogens. Precipitation of immune-related proteins in agarose gel relies on the principle of diffusion to identify proteins. This process is used in radial and Ouchterlong immunodiffusion methods. Today, most laboratories have replaced this method with enzyme-linked immunoassays (ELISA), except in the identification of fungal diseases.

The type of hypersensitivity reaction associated with macrophage activation, cytokine-mediated inflammation is: - Type I Anaphylactic (Immediate hypersensitivity) - Type II Cytotoxic (Antibody mediated and antibody dependent, complement mediated hypersensitivity) - Type III Immune complex mediated hypersensitivity - Type IV Cell mediated hypersensitivity (T-cell dependent)

- Type IV Cell mediated hypersensitivity (T-cell dependent) Type IV Cell-mediated hypersensitivity is associated with macrophage activation. Type IV is characterized by direct target cell lysis and cytokine-mediate inflammation. There are three defining characteristics of type IV hypersensitivity reactions: (1)Type IV delayed-type hypersensitivity involving antigen-sensitized T cells or particles that remain phagocytized in a macrophage and are encountered by previously activated T cells for a second or subsequent time. Delayed hypersensitivity is a major defense mechanism again various intracellular pathogens, including mycobacteria, fungi, and certain parasites. (2) Rejection of foreign tissue grafts, elimination of tumor cells bearing neoantigens. (3) Formation of chronic granulomas. Type I Immediate hypersensitivity is mast cell-derived mediators (vasoactive amines, lipid mediators, and cytokines). Cytokine-mediated inflammation involves eosinophils, neutrophils, and lymphocytes. Type I reactions can range from life-threatening anaphylactic reactions to milder manifestations associated with food allergies. Type II Antibody-mediated hypersensitivity is associated with complement and Fc receptor-mediated recruitment and activation of leukocytes (neutrophils and macrophages). Opsonization and phagocytosis of cells. Abnormalities in cellular function, e.g., hormone or neurotransmitter receptor signaling. Types II and III are initiated by the interaction between antibodies, except IgE and antigen. Three different mechanisms of antibody-mediated injury exist in type II reactions: (1) Antibody-dependent, complement-mediated cytotoxic reactions characterized by the interaction of IgG or IgM antibody with the cell-bound antigen. (2) Antibody-dependent, cell-mediated cytotoxicity that depends on the initial binding of specific antibodies to target cell surface antigens. (3) Antireceptor antibodies that disturb the functioning of receptors. Transfusion reactions are an example of an antibody-dependent, complement-mediated cytotoxic reaction. Hyperacute graft rejection is also an example of a Type II hypersensitivity reaction. Type III Immune complex-mediated hypersensitivity is associated with complement and Fc receptor-mediated recruitment and activation of leukocytes and tissue damage secondary to impaired blood flow. Type III reactions are caused by IgG, IgM, and possibly other antibody types. Immune complexes can cover a spectrum of biological activities, including suppression or augmentation of the immune response by interacting with T and B cells; inhibition of tumor cell destruction; and deposition in blood vessel walls, glomerular membranes, and other sites. These deposits interrupt normal physiologic processes because of tissue damage secondary to the activation of complement and resulting activities.

Which of the following best describes the methodology for FISH? - Uses directly labeled fluorescent nucleotides or probes with reporter molecules that are indirectly detected by fluorescent antibodies or affinity molecules - Signal amplification test that uses signal amplification and alkaline phosphatase - Target amplification test that uses thermal cycling and DNA polymerase - Target amplification test using thermal cycling and DNA ligase

- Uses directly labeled fluorescent nucleotides or probes with reporter molecules that are indirectly detected by fluorescent antibodies or affinity molecules FISH, fluorescent in situ hybridization, uses directly labeled fluorescent nucleotides or probes with reporter molecules that are indirectly detected by fluorescent antibodies or affinity molecules. Branched DNA (bDNA) uses signal amplification by measuring nucleic acid directly by signal amplification with alkaline phosphatase labels. Polymerase chain reaction (PCR) is a test amplification procedure with thermal cycling and DNA polymerase as the enzyme for amplifying the desired sequence. Ligase chain reaction (LCR) is similar to PCR, however, it uses DNA ligase to enhance amplification of the sequence using thermal cycling instead of polymerase like PCR.

What is the correct sequence of the immunologic Epstein-Barr virus (EBV) response in infectious mononucleosis? Key: VCA= viral capsid antigen VCA/IgM =viral capsid antibody (IgM) EA=early antigen EBNA=Epstein-Barr nuclear antigen - VCA, EBNA, VCA/IgM, EA - EA, EBNA, VCA, VCA/IgM - VCA/IgM, EBNA, VCA, EA - EBNA, VCA, EA, VCA/IgM

- VCA, EBNA, VCA/IgM, EA The correct sequence of the immunologic Epstein-Barr virus (EBV) response in infectious mononucleosis is --VCA (viral capsid antigen), EBNA (Epstein-Barr nuclear antigen), VCA/IgM (viral capsid antibody (IgM), and EA(early antigen). Epstein-Barr infected B lymphocytes express a variety of new antigens encoded by the virus. Infection with EBV results in the expression of VCA, EA, and EBNA with corresponding antibody responses. Patients with nasopharyngeal carcinoma have elevated titers of IgA antibodies to EBV replicative antigens, including VCA. These IgA antibodies commonly precede the appearance of the tumor and serve as a prognostic indicator of remission and relapse. VCA is the very first, more obvious antigen to be detectable in infectious mononucleosis. VCA is produced by infected B cells and can be found in the cytoplasm. EBVA is found in the nucleus of all EBV-infected cells. Although the synthesis of EBNA precedes EA synthesis during the infection of B cells, EBNA does not become available for antibody stimulation until after the incubation period of infectious mononucleosis, when activated T lymphocytes destroy the EBV genome-carrying B cells. As a result, antibodies to EBNA are absent or barely detectable during acute infectious mononucleosis. Anti-VCA IgM appears in the sequence at about 3 weeks after infection. It is usually detectable early in the course of infection but is low in concentration and disappears with 2 to 4 months. Anti-VCA IgG is usually detectable with 4 to 7 days after the onset of signs and symptoms, and persists for an extended period, perhaps lifelong. EA is the last serologic marker to be detectable at about the 5th week in the EBV response. Incorrect Answers:EA, EBNA, VCA, VCA/IgM. EA is the last serologic marker to be detectable at about the 5th week in the EBV response. Two components of EA are diffuse early antigen, EA-D, found in the nucleus and cytoplasms of the B cells, and restricted early antigen EA-R, usually found as a mass only in the cytoplasm. EBNA precedes EA synthesis. VCA is the very first more obvious antigen to be detectable in infectious mononucleosis. Anti-VCA IgM appears in the sequence at about 3 weeks after infection. VCA/IgM, EBNA, VCA, EA. Anti-VCA IgM appears in the sequence at about 3 weeks after infection. EBNA precedes EA synthesis. VCA is the very first more obvious antigen to be detectable in infectious mononucleosis. EA is the last serologic marker to be detectable at about the 5th week in the EBV response. EBNA, VCA, EA, VCA/IgM. EBNA precedes EA synthesis. VCA is the very first more obvious antigen to be detectable in infectious mononucleosis. Anti-VCA IgM appears in the sequence at about 3 weeks after infection.

Representative assays in the category of treponemal methods include the listed assays except: - Chemiluminescent immunoassays - Enzyme-linked immunosorbent assays - Venereal Disease Research Laboratory Test - Fluorescent treponemal antibody absorption (FTA-ABS)

- Venereal Disease Research Laboratory Test Venereal Disease Research Laboratory Test is a nontreponemal assay. It is a flocculation test that measures IgM and IgG antibodies to lipoidal material released from damaged host cells, to lipoprotein-like material, and possibly to cardiolipin released from the treponemes. Antilipoidal antibodies are antibodies that are not only produced as a consequence of syphilis and other treponemal diseases, but also may be produced in response to nontreponemal diseases of an acute or chronic nature in which tissue damage occurs. Chemiluminescent immunoassays are treponemal assay that detect specific IgG and/or IgM directed against T. pallidum. These assays are popular because they can be performed at a low cost with automated equipment. Enzyme-linked immunosorbent assays is an attractive treponemal assay because it can discriminate between maternally derived IgG antibodies that cross the placenta from IgM antibodies that cannot cross the placental barrier. The presence of IgG indicates active infection in the newborn. Fluorescent treponemal antibody absorption (FTA-ABS) can be used to confirm that a positive nontreponemal test result has been caused by syphilis rather than by other biological conditions that can produce a positive serologic result.

Flow cytometry is a useful tool in the study all of the following disorders, EXCEPT? - HIV - Leukemia - Viral hepatitis - Lymphoma

- Viral hepatitis Viral hepatitis is diagnosed primarily by ELISA or molecular techniques. Flow cytometry is useful in following the treatment of patients with HIV infection by monitoring CD4 and CD8 cell counts. Immunophenotyping with flow cytometry is critical in the identification of the type of cells that are causing a leukemia or lymphoma.

The most significant class of microbial targets for Natural Killer (NK) cells is: - Bacteria - Parasites - Viruses - Fungi

- Viruses Natural Killer (NK) cells are essential mediators of virus immunity. A deficiency of NK cells in human beings leads to uncontrolled viral replication and a poor clinical outcome. NK cells have a major role in controlling pathogens, especially viruses. Human patients with selective NK-cell deficiencies have recurrent, severe viral infections. NK cells destroy target cells through an extracellular non-phagocytic mechanism referred to as a cytotoxic reaction. NK cells will actively kill virally infected target cells, and if this activity is completed before the virus has time to replicate, a viral infection may be stopped. NK cells are highly responsive to IL-2, IL-7, and IL-12. These cytokines generate high cytokine-activated killer activity in these cells. The immune defense against bacteria is phagocytosis which is a function of polymorphonuclear neutrophils (PMNs), monocytes, and macrophages. Host defense against extracellular bacteria is also offered by the CD4+ subset, TH17. Eosinophils may play a role in the host defense mechanism because of their ability to kill certain types of parasites. An eosinophil can interact with the larval stages of some helminth parasites and damage them through oxidative mechanisms. Certain proteins released from eosinophilic granules damage antibody-coated Schistosoma parasites. In addition, subsets of CD4+ (TH1 and TH2) lymphocytes function in host defense against certain parasites. The TH2 lymphocyte subset mediates host defense against extracellular parasites, including helminths. Host defense against fungi and extracellular bacteria is is offered by the CD4+ subset, TH17.

Immunoglobulin M (IgM) is the characteristically overproduced gene product found in: - Multiple myeloma - Plasma Cell Myeloma - Heavy chain disease - Waldenström's disease

- Waldenström's disease Waldenström's primary macroglobulinemia is considered to be a lymphoplasmacytic lymphoma as defined by World Health Organization classification system. It is a malignant lymphocyte-plasma cell proliferative disorder. Immunoglobulin M (IgM) is the characteristic overproduced gene product. IgG myeloma is the most common form of Multiple Myeloma. Four subtypes of IgG heavy chains are known to exist among patients with IgG myeloma (IgG1, IgG2, IgG3, IgG4). Plasma Cell Myeloma refers to Multiple Myeloma. IgG myeloma is the most common form of Multiple myeloma. Heavy Chain disease is characterized by the presence of monoclonal proteins composed of the heavy-chain portion of the immunoglobulin molecule. Alpha heavy-chain disease is the most common of the heavy-chain gammopathies.

When should acute and convalescent blood specimens be collected from a patient for the detection of antibody concentration related to a specific infectious disease? 2 weeks apart4 weeks apart3 months apart6 months apart - 4 weeks apart - 3 months apart - 6 months apart

2 weeks apart4 weeks apart3 months apart6 months apart In obtaining specimens for serologic testing, it is important to consider the phase of the disease and the condition of the patient at the time of specimen collection. This is especially important in assays for the diagnosis of infectious diseases. If patient serum is being tested for the concentration (titer) of antibodies for a specific infectious organism, a blood specimen should be drawn and the serum frozen during the acute phase of the illness (when the disease is first discovered or suspected), and a second blood sample drawn during the convalescent phase, usually about 2 weeks later. A difference in the antibody titer may be noted when the two different samples are tested concurrently. In general, 4 weeks is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 3 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). In general, 6 months is too long of a gap between collecting acute and convalescent blood specimens for antibody concentrations (titers). However, some infectious diseases, such as Legionnaire's disease or hepatitis, may not manifest a rise in titer until months after the acute infections.