Transplantation
Which region of the immunoglobulin molecule can bind antigen? A) Fab B) Fc C) CL D) CH
A) Fab The Fab (fragment antigen binding) is the region of the immunoglobulin molecules that can bind antigen. 2 Fab fragments are formed from hydrolysis of the immunoglobulin molecule by Papain. Each consists of a light chain and the V(H) and C(H1) regions of the heavy chain. The variable regions of the light and heavy chains interact, forming a specific antigen-combining site.
Select the best donor for a man, blood type AB, in need of a kidney transplant: A) His brother, type AB, HLA matched or class II antigens B) His mother, type B, HLA matched for class I antigens C) His cousin, type O, HLA matched for major class II antigens D) Cadaver donor, type Oh, HLA matched or some class I and II antigens
A) His brother, type AB, HLA matched or class II antigens A twin or sibling donor of the same blood type and HLA matched for class II antigens is the best owner in this situation. Class II antigens (HLA - D, HLA - DR, DQ, and DP) determine the ability of the transplant recipient to recognize the graft. The HLA genes are located close together on chromosome 6, and crossover between HLA genes is rare. Siblings with closely matched class II antigens most likely inherited the same class I genes. The probability of siblings inheriting the same HLA haplotypes from both parents is 1:4.
Indications for an autologous hematopoietic progenitor cell (HPC) transplant include patients who have: A) Hodgkin lymphoma with high-dose chemotherapy B) congenital Hemoglobinopathies C) congenital immunodeficiency disorders D) inborn errors of metabolism
A) Hodgkin lymphoma with high-dose chemotherapy Autologous HPC transplants are used to restore hematopoietic rescue after high-dose chemotherapy. All the other clinical situations are treated with allogeneic HPC transplants. [AABB Tech Manual 2017, p 668;Harmening 2012, p 392]
A patient underwent renal transplant, receiving a kidney from an unrelated donor. This type of transplant is termed: A) allograft B) syngraft C) autograft D) xenograft
A) allograft Allograft is transplantation between nonidentical individuals of the same species. [Mahmoudi 2016, p 62]
Which of the following precludes cadaveric renal transplantation? A) positive cross-match B) Donor blood type O C) two antigen HLA match with donor D) Blood pressure of 180/100mmHg E) Hemoglobin level of 8.2g/dL
A) positive cross-match A positive cross-match means that the recipient has circulating antibodies that are cytotoxic to donor-strain lymphocytes. This incompatibility, which almost always leads to an acute humoral rejection of the graft, precludes transplantation
What is an alloreaction?
An alloreaction is the response of one individual against antigens (proteins) which differ among members of the same species.
What is an alloantigen?
An antigen that differs between members of a species. The alloantigen's that are involved in tissue and bone marrow transplantation are histocompatibility (MHC or HLA) proteins.
Which types of graft are most likely to be successful?
Autografts and syngeneic/isografts are likely to be successful because autografts and syngeneic/isografts and the recipient have identical MHC.
HLA typing of a family yields the following results: Source locus A locus B Father (8, 12) (17, 22) Mother (7, 12) (13, 27) On the basis of these genotypes, predict the possibility of ankylosing spondylitis in this percentage of their children: A) 25% of their children B) 50% of their children C) 75% of their children D) 100% of their children
B) 50% of their children HLA-B27 is associated with ankylosing spondylitis. There is a 50% chance of the mother will transmit her B27 allele to her children. [Mahon 2006, p 172]
The area of the immunoglobulin molecule referred to as the hinge region is located between which domains? A) V(H) and V(L) B) C(H1) and C(H2) C) C(H2) and C(H3) D) C(H3) and V(L)
B) C(H1) and C(H2) Immunoglobulin structure, hinge is between CH1 and C H2
A cross-match is performed by incubating: A) Donor serum with recipient lymphocytes and complement B) Donor lymphocytes with recipient serum and complement C) Donor lymphocytes with recipient lymphocytes D) Recipient serum with a known panel of multiple donor lymphocytes E) Recipient serum with donor red blood cells and complement
B) Donor lymphocytes with recipient serum and complement The purpose of a crossmatch is to determine whether the recipient has circulating antibodies against donor HLA antigens. Such antibodies do not occur naturally, but rather are the result of prior sensitization during pregnancy, blood transfusions, or previous transplantation. A complement-dependent lymphocytotoxicity cross-match is performed by adding recipient serum and complement to donor cells (T cells, B cells, or monocytes). If specific anti-donor antibodies are present, antibody binding results in complement fixation and cell lysis. This is detected by addition of a vital dye, which is taken up by the damaged cell membrane, resulting in a positive crossmatch. If a positive cross-match is detected to donor T cell (HLA Class I), transplantation will result in hyperacute rejection.
Which of the following systems plays an important role in Transfusion-Related Acute Lung Injury (TRALI), transfusion associated graft-versus-host disease (TA-GVHD), platelet refractoriness, and Febrile Non-hemolytic Transfusion Reactions (FNHTR) as well as in hematopoietic stem and organ transplantation rejection? A) Rh B) HLA C) Lewis D) Diego
B) HLA human leukocyte antigens (HLA) are found on most nucleated body cells with some exceptions such as neurons. The antigens and antibodies of this system play a significant role in several different transfusion -related reactions and in transplantation rejections. [AABB Tech Manual 2017, p 447;Harmening 2012, p 376]
Bone marrow transplant donors and the recipients must be matched for which antigen system(s)? A) ABO-Rh B) HLA C) CD4/CD8 D)P1^a1
B) HLA mismatches and HLA antigens between a donor and recipient of a bone marrow transplant can lead to graft-versus-host disease, in which T lymphocytes in the bone marrow graft mount an immune response against foreign histocompatibility antigens of the immunocompromised recipient. [Stevens 2017, p 266]
Which method, classically used for HLA - D typing, is often used to determine the compatibility between a living organ donor and recipient? A) Flow cytometry B) Mixed lymphocyte culture (MLC) C) Primed lymphocyte test (PLT) D) Restriction fragment length polymorphism (RFLP)
B) Mixed lymphocyte culture (MLC) Flow cytometry can be used in transplantation to type serologically defined HLA antigens. The one - way mixed lymphocyte reaction is used to identify HLA-D antigens on the donor's lymphocytes and is used for cross matching living donors with transplant recipients. The assay is time-consuming and would not be used as part of a workup for a cadaver donor transplant. HLA-D incompatibility is associated with the recognition phase of allograft rejection. The primed lymphocyte test is used to identify HLA-DP antigens.
Interpret the following microcytotoxicity results: A9 and B12 cells damaged; A1 and Aw19 cells intact. A) Positive for A1 and Aw19; negative for A9 and B12 B) Negative for A1 and Aw19; positive for A9 and B12 C) error in test system; retest D) Impossible to determine
B) Negative for A1 and Aw19; positive for A9 and B12 The microcytoTOXICITY test is based upon the reaction of specific anti-Sarah and HLA antigens on test cells. Cells damaged by the binding of antibodies and complement are detected with a supra-vital dye such as eosin.
SITUATION: Cells type negative for all HLA antigens and a complement-dependent cytotoxicity assay. What is the most likely cause? A) Too much supravital dye was added B) Rabbit complement is inactivated C) All leukocytes are dead D) antisera is too concentrated
B) Rabbit complement is inactivated Inactive rabbit complement may not become fixed to antibodies that have bound test leukocytes; therefore, no lysis of cells will occur. When the supravital dye is added, all cells will appear negative (exclude the dye) for all HLAs.
Use of only male donors as a source of plasma intended for transfusion is advocated to reduce which type of reaction? A) allergic B) TRALI C) hemolytic D) T ACO (circulatory overload)
B) TRALI TRALI is most commonly caused by donor HLA or granulocyte-specific antibodies (human neutrophil antibodies, HNA) that react with the recipient antigens, causing damage to the lung basement membrane and bilateral pulmonary edema within 6 hours of transfusion. Multiparous females are more likely to have antibodies than males. Using male donors as the sole source of plasma products as a strategy for reducing the risk of TRALI. [AABB Tech Manual 2017, p 582;Harmening 2012, p 376]
Which of the following is associated with the risk of developing a transfusion associated graft-versus-host disease (TA-GVHD)? A) patients receiving leukocyte reduced blood components B) directed donation from first-degree family member C) patients transfused with irradiated blood components D) autologous blood donation prior to surgery
B) directed donation from first-degree family member Patients who are immunocompromised, on immunosuppressive drugs, of neonatal age, and those with disorders such as acute leukemia and lymphoma are at risk for TA-GVHD. TA-GVHD can also occur in non-immunocompromised patients if the donor is homozygous for an HLA haplotype and the recipient is heterozygous for that allele, as could be the case in a first-degree relative and a directed donation. This allows the donor lymphocytes to mount an immune response against the recipient, resulting in nearly always fatal TA-GVHD. Blood components for at risk patients should be irradiated to inactivate donor lymphocytes. [AABB Tech Manual 2017, p 590;Harmening 2012 p 381; Johns 2015 p 231]
How is HLA typing using the investigation of genetic diseases? A) for prediction of the severity of the disease B) for genetic linkage studies C) for direct diagnosis of disease D) is not useful in this situation
B) for genetic linkage studies HLA typing is useful in predicting some genetic diseases and for genetic counseling because certain HLA types show strong linkage to some diseases. HLA typing is not specifically used to diagnose a disease or assess its severity. In linkage studies, a disease gene can be predicted because it is located next to the locus of a normal gene with which it segregates. For example, the relative risk of developing ankylosing spondylitis is 87% in persons who are positive for HLA-B 27. An analysis of family pedigrees for the linkage marker and disease can be used to determine the probability that a family member will inherit the disease gene.
HLA antibodies are: A) naturally occurring B) induced by multiple transfusions C) directed against granulocyte antigens only D) frequently cause hemolytic transfusion reactions
B) induced by multiple transfusions HLA antibodies are formed in response to pregnancy, transfusion or transplantation and are therefore not naturally occurring. They are associated with febrile non-hemolytic transfusion reactions and TRALI. They are directed against antigens found on granulocytes and other cells such as platelets. [AABB Tech Manual 2017, p 447]
What is the main advantage of the recovery and re-infusion of autologous stem cells? A) It slows the rate of rejection of transplanted cells B) it prevents graft-versus-host disease C) no HLA testing is required D) Engraftment occurs in a more efficient sequence
B) it prevents graft-versus-host disease The main advantage to the patient from the reinfusion of autologous stem cells is that the procedure prevents graft-versus-host disease, especially in the immunocompromised patient. Although HLA testing is not required, this is not the primary advantage for patient care.
What type of serological testing does the blood bank technologist perform when determining the blood group of a patient? A) genotyping B) phenotyping C) both genotyping and phenotyping D) polymerase chain reaction
B) phenotyping Phenotyping, or the physical expression of a genotype, is the type of testing routinely performed in the blood bank. An individual, for example, may have the AO genotype but phenotypes as group A.
The purpose of irradiation of blood components is to: A) prevent post-transfusion purpura B) prevent graft-versus-host disease C) sterilize components D) sees prevent non-cardiogenic pulmonary edema
B) prevent graft-versus-host disease irradiation inhibits proliferation of T cells and subsequent GVHD. [Harmening 2012, p 382]'s
Which of the following statements is correct about hematopoietic progenitor cell (HPC) transplantation? A) successful allogeneic transplantation requires that at least 5 out of 10 HLA loci match B) sources for HPC collection include bone marrow, umbilical cord blood (UCB), and mobilized peripheral blood C) bone marrow collection of HPC is preferred to Apheresis collection because of fewer side effects D) HPC products are infused into the patient over a period of at least 6 hours
B) sources for HPC collection include bone marrow, umbilical cord blood (UCB), and mobilized peripheral blood Bone marrow, UCB, and mobilized peripheral blood are the most common sources of HPCs. Successful allogeneic transplants require 8/10 or 10/10 HLA loci matches. Apheresis HPC collections have fewer adverse effects than bone marrow collection. HPC products are generally administered by central line infusion and as quickly as the patient can tolerate. [AABB Tech Manual 2017, p 667;Harmening 2012, p 393]
Testing blood donors the presence of antibodies to human neutrophil antigens (HNAs) can help prevent which of the following adverse events associated with transfusion? A) transfusion-associated circulatory overload (TACO) B) transfusion-related acute lung injury (TRALI) C) anaphylaxis D) citrate toxicity
B) transfusion-related acute lung injury (TRALI) One mitigation strategy to help prevent TRALI is to eliminate the transfusion of plasma -containing components that demonstrate both HNA and HLA antibodies. Other mitigation strategies include the use of plasma-containing products from only male donors, never-pregnant females or females tested since their last pregnancy and found to be negative for both HLA and HNA antibodies. [AABB Tech Manual, 2017, p 428]
T regulator cells, responsible for controlling autoimmune antibody production, express which of the following phenotypes? A) CD3, CD4, CD8 B) CD3, CD8, CD25 C) CD3, CD4, CD25 D) CD8, CD25, CD 56
C) CD3, CD4, CD25 T regulator cells are believed to be the primary immune suppressor cells and express CD3, CD4, and CD25. CD25 is the interleukin 2 receptor. CD25 may be expressed by activated T cells, but is constitutively expressed by the T-regulator cells. CD25 expression on T-regulator cells occurs in the thymus and is regulated by the FOXP3 protein.
The most widely accepted QC test to measure probable Hematopoietic Progenitor Cell (HPC) engraftment is: A) clonogenic essay B) cell viability C) CD34 positive cell enumeration D) manual differential
C) CD34 positive cell enumeration CD34+ enumeration is the most widely used and accepted, I'll be at surrogate, QC test to evaluate HPC engraftment. [AABB Tech Manual 2017, p 676]
Which of the following statements is true about Class II HLA antigens? A) they are found on the surface of most nucleated cells. B) Bg antigens are part of HLA class II C) HLA-DR, HLA-DQ and HLA-DP are all class II D) they are only located on neurons and platelets
C) HLA-DR, HLA-DQ and HLA-DP are all class II HLA-DR, HLA-DQ and HLA-DP are class II antigens which are only found on monocytes, macrophages, Be lymphocytes, dendritic cells, early hematopoietic cells and intestinal epithelial cells. [AABB Tech Manual 2017, p 436;Harmening 2012, p 476]
What is the major barrier to successful transplantation across animal species (xenotransplantation)? A) Acute rejection B) Chronic rejection C) Hyperacute rejection D) Infection E) ABO incompatibility
C) Hyperacute rejection The major barrier to successful xenotransplantation has been hyperacute rejection, which refers to the binding of preformed human antibodies to donor endothelial cells. This results in the activation of complement, cell lysis, and eventually vascular thrombosis
Which of the following are efficient antigen-presenting cells found in the epidermis? A) Macrophages B) T cells C) Langerhans cells D) Dendritic cells E) B cells
C) Langerhans cells Processing and presentation of antigen in association with class II molecules is critical for activation of T cells. Langerhans cells are potent antigen-presenting cells (APCs) found in skin. Macrophages are the major APCs in the body Dendritic cells are APCs found in lymphoid tissue
Chronic transplant rejection is a cell-mediated and humoral immune response that involves all of the following EXCEPT: A) narrowing and occlusion of craft blood vessels B) reaction of T and B cells to graft antigen C) antibodies to MHC antigens on white cells D) arteriosclerosis of the graft arterial wall
C) antibodies to MHC antigens on white cells White cell antigen interacts with pre--existing antibodies to repeated pregnancy or blood transfusions. It is a hyperacute reaction. [Mahmoudi 2016, p 64]
9 days after being transfused within HLA-matched platelet transfusion, the patient develops a fever, watery diarrhea, skin rash and demonstrates increased liver enzymes. This patient may have transfusion-associated: A) allergic urticaria reaction B) hepatitis C C) graft versus host disease D) septicemia with endocarditis
C) graft versus host disease Patients who develop TA-GVHD is have these types of symptoms. This complication of transfusion has a mortality rate higher than 90%. [AABB Tech Manual 2017, p 590]
HLA-B8 antigen has been associated with which of the following pairs of diseases? A) ankylosing spondylitis and myasthenia gravis B) celiac disease and ankylosing spondylitis C) myasthenia gravis and celiac disease D) Reiter disease and multiple sclerosis
C) myasthenia gravis and celiac disease Individuals who are HLA-B8-Positive have a 5 times greater risk than HLA-B8-Negative persons of developing myasthenia gravis, and a 9X greater risk of developing celiac disease over a lifetime. [Turgeon 2009, p 429]
A 28-year-old man is seen by a physician because of several months of intermittent low back pain. The patient's symptoms are suggestive of ankylosing spondylitis. Which of the following laboratory studies would support this diagnosis? A) a decreased synovial fluid CH 50 level B) low serum CH 50 level C) positive HLA-B27 antigen test D) rheumatoid factor in the synovial fluid
C) positive HLA-B27 antigen test More than 95% of patients with ankylosing spondylitis are positive for the HLA-B 27 antigen; therefore, a positive result for this test would support the diagnosis. [Mahon 2006, p 181]
Incompatibility by which of the following procedures is an absolute contraindication to allotransplantation? A) MLC (mixed lymphocyte culture) B) HLA typing C) Rh typing D) ABO grouping
D) ABO grouping ABO incompatibility results in hyperacute rejection. This reaction is mediated by anti-A or anti-B antibodies that naturally occur in individuals who lack the corresponding A or B antigen. [Stevens 2017, p 266]
A renal transplant recipient is found to have a rising creatinine level and reduced urine output. The physician orders a "Urine PCR" assay. When you call to find out what organism the physician wants to identify, you are told: A) Hepatitis C virus B) Legionella pneumophila C) EBV D) BK virus
D) BK virus BK virus is a polyOma virus that can cause renal and urinary tract infections. The virus is an opportunistic pathogen and has become a well-recognized cause of poor renal function in kidney transplant recipients. Antibody testing is not practical or useful for this infection. The principal diagnostic assays are urinary cytology, and specific BK virus PCR testing in urine and serum. Although Legionella pneumophila can be diagnosed through a urinary anagen assay, that organism is not a primary cause of renal insufficiency and transplant patients.
Graft-versus-host disease (GVHD) has occurred with the transplantation of which of the following? A) Kidney B) Lung C) Heart D) Bone Marrow E) Pancreas
D) Bone Marrow Donor-type lymphoid cells transplanted within a graft may recognize the host's tissue as foreign and mount an immune response against the host. This response, termed graft-versus-host disease (GVHD), is common in bone marrow transplantation and is an important source of morbidity and mortality. Treatment requires more aggressive immunosuppression. Current cliinical practice includes depletion of lymphocytes from the marrow graft in order to prevent the development of GVHD. GVHD has been documented following liver transplantation, presumably because of the large amount of lymphoid tissue in the donor liver. GVHD has not been described following heart, lung, pancreas, or kidney transplantation.
Which of the following cell surface molecules is classified as an MHC class II antigen? A) HLA - A B) HLA - B C) HLA - C D) HLA - DR
D) HLA - DR The MHC region is located on the short arm of chromosome 6 and codes for antigens expressed on the surface of leukocytes and tissues. The MHC region genes control immune recognition; their products include the antigens that determine transplantation rejection. HLA - DR antigens are expressed on B cells. HLA=DR2, DR3, DR4, and DR5 antigens show linkage with a wide range of autoimmune diseases
MHC class I includes which peptides/proteins? A) complement B) HLA-A, B, C C) cytokines D) HLA-DP, DQ, DR
D) HLA-DP, DQ, DR MHC class I codes for HLA-A, B, C. MHC class II codes for HLA-DR, DQ, DP. MHC class III codes for complement and cytokines. [Stephen 717, p 264]
Which of the following genes is not in the MHC class one region? A) HLA-A B) HLA-B C) HLA-C D) HLA-DR
D) HLA-DR Class one region contains HLA-A, HLA-B, and HLA-C. Class II region contains HLA-DR
A 37-year old man suffers extensive burns of both lower extremities. He received allografts of skin, but these were rejected starting about 11 days after the graft procedure. The main cause of rejection is: A) B-cell mediated IgG antibody response B) B cell antibody switching response of IgM to IgG antibodies C) IgE-mediated release of mast cells D) T cell-mediated reaction, mainly CD8-positive cytotoxic T cells E) Nitric oxide release by macrophages
D) T cell-mediated reaction, mainly CD8-positive cytotoxic T cells Allograft rejection is an acute process that occurs 11 to 14 days after placement of the allograft (grafts among genetically different individuals of the same species), in this case skin allografts, that is mediated by T cells. Most of the killing of allograft cells is carried out by cytotoxic CD8-positive T cells. B cell antibody responses, IgE, and nitric oxide do not play a role in the rejection of allografts. [Levinson, 7/e, pp396]
A transplant patient began to show signs of rejection 8 days after receipt of the transplanted organ, and the organ was removed. What immune elements might be found in the rejected organ? A) Antibody and complement B) Primarily antibody C) Macrophages D) T cells
D) T cells Acute rejection occurs within 3 weeks of transportation. The immune element most likely to be involved in an acute rejection is the T cell in a type IV, delayed hypersensitivity (cell-mediated) reaction. Preformed anti-body, and possibly complement, is usually involved in hyper acute (immediate) rejection and chronic rejection
A 51-year-old man who had an allogeneic bone marrow transplant about 2 months ago complains of anorexia and an erythematous maculopapular rash. On physical examination, he is jaundiced and he has hepatosplenomegaly. The cause of his disease is: A) B cell-mediated IgG antibody response B) Transplanted MHC I proteins that match the recipient's cells C) IgE mediated release of mast cells D) Transplanted allogeneic T cells E) Nitric oxide release by macrophages
D) Transplanted allogeneic T cells Graft-versus-host disease (GVHD) can develop in immunosuppressed persons who receive allogeneic bon marrow transplants that contain allogeneic T cells transferred with the donor's stem cells or develop from it. The donor cells respond to histocompatibility antigens present on the recipient's cells, which are not present on the donor cells. Bone marrow contains immunocompetent T cells; liver, kidney, and skin do not have a sufficient number of immunocompetent T cells to elicit GVH reactions. MHC I proteins identical in donor and recipient do not play a role in GVHD, but GVHD can ensue from a mismatch of MHC I and II proteins between donor and recipient. Antibody and nitric oxide are not involved in GVHD [Levinson, 7/e, pp398. Braunwald, 15/e, pp739-742]
What method may be used for tissue typing instead of serological HLA typing? A) PCR B) Southern blotting C) RFLP D) all of the others
D) all of the others PCR, Southern blotting, and testing for RFLPs, may all be used to identify HLA genes. Many laboratories use PCR technology for the routine determination of HLA type.
The procedure for compatibility testing and organ transplant medicine is very similar for the donor and the recipient. One additional procedure that the recipient must undergo that is not relevant to donor testing is: A) ABO typing B) HLA typing C) CMV testing D) anti-HLA antibody testing
D) anti-HLA antibody testing As HLA, CMV, and ABO typing is required of donors and recipients, anti-HLA antibody testing is required in addition or recipients to eliminate unacceptable donors. [Rittenhouse-Olson 2018, p 235]
MHC class III genes code for? A) antigens B) antibodies C) lymphocytes D) complement
D) complement MHC class I codes for HLA-A, B, C. MHC class II codes for HLA-DR, DQ, DP. MHC class III codes for complement and cytokines. [Stephen 717, p 264]
Genes of the major histocompatibility complex (MHC): A) code for HLA-A, HLA-B, and HLA-C antigens only B) are linked to genes in the ABO system C) are the primary genetic sex-determinants D) contribute to the coordination of cellular and humoral immunity
D) contribute to the coordination of cellular and humoral immunity MHC consists of both class I and class II HLA antigens. Discrimination of self from nonself is the primary function of the HLA system and involves many immune responses. [AABB Tech Manual 2017, p 440]
Patient in the immediate post-bone marrow transplant. Has a hematocrit of 21%. The red cell product of choice for this patient would be: A) Packed B) saline washed C) microaggregate filtered D) irradiated
D) irradiated Bone marrow transplant patients are at risk for transfusion associated graft-versus-host disease(TA-GVHD) and therefore should receive irradiated blood products. [AABB Tech Manual 2017, p 590]
To prevent donor lymphocytes from engraftment in the bone marrow of an immunosuppressive patient, all transfusion products must be: A) washed B) leukocyte-reduced C) treated with UV light D) irradiated
D) irradiated Donor lymphocytes from transfused blood can cause transfusion-associated graft-versus-host disease (TA-GVHD) and immunosuppressed patients. The only method that inactivates lymphocytes is a radiation of the blood products. [AABB Tech Manual 2017, p 590;Harmening 2012 p 381; Johns 2015 p 231]
Which of the following patient groups is at risk of developing graft- versus-host disease? A) full-term infants B) patients with history of febrile transfusion reactions C) patients with a positive direct anti-globulin test D) recipients of blood donated by immediate family members
D) recipients of blood donated by immediate family members Blood from a family member may be homozygous for a shared HLA haplotype, allowing donor lymphocytes to engraft and the recipient and cause transfusion-associated GVHD. [AABB Tech Manual 2017, p 590]
In a laser flow cytometry, applying a voltage potential to sample droplets as they stream past the light beam and using charged deflector plates results in: A) an emission of red fluorescence from cells labeled with fluorescein Isothiocyanate B) an emission of green fluorescence from cells labeled with rhodamine C) a 90° light scatter related to cell size D) the separation of cells into subpopulations based on their charge
D) the separation of cells into subpopulations based on their charge Laser flow cytometry is the underlying principle of cell sorting into subpopulations. [Turgeon 2009, p 174]
What is acute rejection?
Develops over a period of several days. Alloreactive recipient T sells recognize donor HLA presented by donor dendritic cells (direct recognition) and migrate to the graph to attack it.CD4 and CD8 T cells can mediate damage.
What is chronic rejection?
Develops over months to years and is mediated primarily by antibody against HLA. As donor cells die, they release donor HLA proteins that are processed and presented by recipient dendritic cells and B cells (indirect recognition).
How many types of class 1 protein are expressed on somatic cells?
Generally, six proteins are expressed. A child receives an HLA-A, HLA-B, and HLA-C from each parent. The high degree of polymorphism and HLA proteins means that for locus, children receive different alleles from each parent. Co-dominance means that all alleles are expressed
What distinguishes the alloreaction in solid organ transplants from the alloreaction in bone marrow transplants?
In solid organ transplants alloreactive recipient (host) T cells attacked the donated organ. In bone marrow transplants, alloreactive donor T cells attacked the recipient (host) sees.
Why is it unnecessary to do HLA typing for blood transfusions?
It is unnecessary to do HLA typing for blood transfusions because red blood cells RBC do not express HLA
Which sales would you expect to see infiltrating a "rejected" graft? In other words, which cells mediate craft rejection?
Lymphocytes, phagocytes (macrophages and neutrophils), and other inflammatory cells (mast cells, basophils) mediate graft rejection
What is hyper acute rejection?
Occurs rapidly within hours and is completed before the graft establishes itself. It is the result of pre-existing antibodies to either blood groups or MHC.
A 14-year-old boy receives a bone marrow transplant from his HLA identical sister. Several weeks after transplantation, he has a slightly elevated serum bilirubin, mild diarrhea, and a maculopapular rash on his extremities. What is the most likely cause the symptoms?
The cause of the boys symptoms is stage I graft-versus-host disease(GVHD), most likely due to T cells in the graft recognizing H-Y antigen derived peptides.
