2015 Fall - Patho I, Ch.9 - Alterations in Immunity and Inflammation

"What does the 'combined' mean in severe combined immunodeficiency disease?" asks Mrs. Quoit, whose son has SCID.

"Combined" refers to two parts of the immune system that do not work in SCID: the antibody part, also called humoral immunity, and the T lymphocyte part, also called cell-mediated immunity. In some other immunodeficiencies, one or the other of the parts does not work, but because both parts are not working in SCID, it is called a combined immunodeficienc.

Which definition is true? A. Allergy means the deleterious effects of hypersensitivity. B. Immunity means an altered immunologic response. C. Hypersensitivity means the protective response to an antigen. D. Autoimmunity means the normal response to foreign antigens.

A. Allergy means the deleterious effects of hypersensitivity. (Allergy means the deleterious effects of a hypersensitivity reaction.)

Histamine release leads to which of the following? (Select all that apply.) A. Bronchial smooth muscle contraction B. Bronchoconstriction C. Decreased vascular permeability D. Vasoconstriction E. Edema

A. Bronchial smooth muscle contraction B. Bronchoconstriction E. Edema (Histamine contracts bronchial smooth muscle, which causes bronchoconstriction. Vascular permeability, edema, and vasodilation also increase.)

What antibody binds to a mast cell? A. Cytotropic B. Allergen C. Antigen D. Fc

A. Cytotropic (A cytotropic antibody (also called a skin-sensitizing antibody or reagin) is the antibody that binds to the mast cell. An allergen is an environmental antigen that induces an allergic response. An antigen stimulates the immune response and antibody to bind to the mast cell. The Fc is the portion of the mast cell where IgE binds.)

Which statement is true of serum sickness? A. The formation of immune complexes in the blood cause serum sickness. B. It is the deposition of complexes in the blood vessels. C. It occurs through cytotoxic T cells. D. It binds antigen to the cell surface.

A. The formation of immune complexes in the blood cause serum sickness. (Serum sickness reactions are caused by the formation of immune complexes in the blood and their deposition in target tissues. An Arthus reaction deposits complexes into the walls of blood vessels. Type IV mechanisms occur through either cytotoxic T lymphocytes or lymphokine-producing T-helper (Th) 1 cells. Antigen is bound to the cell surface in type II reactions.)

Which statement is true regarding hypersensitivity reactions? A. They require sensitization against a particular antigen. B. They occur after the primary immune response. C. Reactions are always delayed. D. The most delayed reaction is anaphylaxis.

A. They require sensitization against a particular antigen. (A hypersensitivity reaction requires sensitivity to an antigen and occurs after an adequate secondary immune response. These reactions may then be immediate or delayed. The most immediate reaction is anaphylaxis.)

Define: Hypersensitivity

Altered immunologic response to an antigen that results in disease or damage to the host

What does ANA mean? Why is it important in SLE (systemic lupus erythematosus)?

Antinuclear antibodies (antibodies against normal nuclear antigens) are important autoantibodies that participate in the pathophysiology of SLE.

Hypogammaglobulinernia is classified as a ______ lymphocyte deficiency.

B

Which is an example of an alloimmune disease? A. Tuberculin reaction B. Graves disease C. Contact dermatitis D. Penicillin allergy

B. Graves disease (Graves disease, myasthenia gravis, immune thrombocytopenic purpura, alloimmune neutropenia, and systemic lupus erythematosus are all examples of alloimmune diseases during which the child can be affected because the mother has the disease. Tuberculin reaction is a type IV reaction. Contact dermatitis is a type I reaction. Penicillin is an allergen that induces type I hypersensitivity.)

Which statement best describes a type I reaction? A. Most type I reactions are mediated by IgA. B. Most type I reactions are allergic. C. Most occur against medications. D. Seldom does this type contribute to autoimmune diseases.

B. Most type I reactions are allergic. (Most type I reactions are allergic. They are mediated by IgE. Most occur against environmental antigens and can contribute to some autoimmune diseases.)

Which statement is true regarding atopic individuals? A. If one parent has allergies, then a 4% chance exists that the offspring will have similar allergies. B. If two parents have allergies, then a 50% chance exists that their offspring will have similar allergies. C. Atopic individuals tend to produce higher quantities of IgE. D. No genes are associated with an atopic state.

C. Atopic individuals tend to produce higher quantities of IgE. (Higher quantities of IgE are present in atopic individuals. If one parent has an allergy, then the individual has a 40% of having allergies; with two parents, the individual has an 80% of having allergies. Multiple genes have been associated with the atopic state.)

The Arthus reaction is an example of which type of sensitivity reaction? A. I B. II C. III D. IV

C. III (The Arthus reaction is a type III hypersensitivity reaction.)

Which statement is true regarding unmatched packed red blood cell (RBC) transfusions? A. Only three different RBC antigens have been identified. B. Approximately 80 major carbohydrate antigens exist. C. People with O type blood have neither A or B antigens. D. A person with type A blood contains anti-O antibodies.

C. People with O type blood have neither A or B antigens. (Type O blood does not contain type A or B antigens. However, 80 major different RBC antigens are present. A person with type A blood carries anti-B antibodies and a person with type B blood carries anti-A antibodies. Those with type O blood have anti-A and anti-B antibodies.)

"My physician said my cancer drugs gave me a secondary immunodeficiency, so I get sick easily," says Mr. Erie. "I think it is important! Why did she say it is secondary?"

Calling it a secondary immunodeficiency does not mean that It is unimportant. It means that the immunodeficiency was caused by something outside your immune system, rather than being a problem that started with your immune system. As you know, the cancer drugs suppressed your immunity. That is why we call it secondary immunodeficiency. We think it is very important also and are working to protect you from infection.

Which statement is true regarding a type IV allergic reaction? A. Is immediate in its action. B. Is infiltrated with B cells. C. Has a red, soft center. D. Can be transferred by cells.

D. Can be transferred by cells. (Type IV hypersensitivity reactions can be transferred by cells but not by serum. Their actions are delayed because their onset takes from 24 to 72 hours. The site is infiltrated with T lymphocytes and macrophages. A clear hard center surrounds the erythema (redness).)

Define: Allergy

Deleterious effects of hypersensitivity to environmental antigens

Histamine released from mast cells causes signs and symptoms of inflammation by binding to (HI, H2) receptors.

H1

Ayisha Walker, a 36-year-old woman studying medicine, has aching in her joints (arthralgia) and a new rash on her face. She states that the rash gets worse when she goes out into the sun. She also feels fatigued and gets a sharp pain in her chest when she breathes deeply. She has had "flare-ups" of these symptoms from time to time in the past, but this is the worst episode ever. Laboratory Results • Serum electrolytes normal • Hematocrit and hemoglobin low; platelet count slightly low; white blood count normal • Blood urea nitrogen (BUN) and creatinine elevated; protein present in the urine • Chest radiograph shows a small collection of pleural fluid • Anti-DNA antibodies positive; antinuclear antibody (ANA) positive Ms. Walker's diagnosis is systemic lupus erythematosus (SLE). Which of Ms. Walker's laboratory results indicate renal dysfunction? Is renal dysfunction associated with SLE, or is it more likely that she also has a renal disease unrelated to SLE?

Her elevated BUN and creatinine and urine protein indicate renal dysfunction, which is common with SLE.

Define: Alioimmunity

Immune system of one individual produces an immunologic reaction against tissues of another individual

"Why not just look at this TB skin test in an hour or so?" asks Mr. Rush. "I am going on a business trip tomorrow and cannot come back later this week."

It takes 1 to 3 days for any reaction to develop, so we would not see any response in an hour. The type of response that causes a positive test is called a delayed hypersensitivity response because it arises so slowly. It is important for you to have a qualified person look at it later this week. Let us talk about how you can arrange that.

Genetic predisposition to autoimmunity often involves (MHC, CD4) alleles.

MHC

Ayisha Walker, a 36-year-old woman studying medicine, has aching in her joints (arthralgia) and a new rash on her face. She states that the rash gets worse when she goes out into the sun. She also feels fatigued and gets a sharp pain in her chest when she breathes deeply. She has had "flare-ups" of these symptoms from time to time in the past, but this is the worst episode ever. Ms. Walker's diagnosis is systemic lupus erythematosus (SLE). Why should Ms. Walker be taught to avoid sunlight?

Photosensitivity is common with SLE. Her rash is most prominent on sun-exposed areas of her skin.

Ayisha Walker, a 36-year-old woman studying medicine, has aching in her joints (arthralgia) and a new rash on her face. She states that the rash gets worse when she goes out into the sun. She also feels fatigued and gets a sharp pain in her chest when she breathes deeply. She has had "flare-ups" of these symptoms from time to time in the past, but this is the worst episode ever. Physical Examination • Vital signs normal • Facial rash over her cheeks and the bridge of her nose • Discoid scaling red rash on extremities, especially the extensor surfaces of the arms • Finger and ankle joints with pain and stiffness on passive and active movement • Chest exam with pleural friction rub heard on deep inspiration • Cardiac, abdominal, and neurologic examinations normal Laboratory Results • Serum electrolytes normal • Hematocrit and hemoglobin low; platelet count slightly low; white blood count normal • Blood urea nitrogen (BUN) and creatinine elevated; protein present in the urine • Chest radiograph shows a small collection of pleural fluid • Anti-DNA antibodies positive; antinuclear antibody (ANA) positive Ms. Walker's diagnosis is systemic lupus erythematosus (SLE). What other aspects of her history, physical exam, and laboratory results are manifestations of SLE?

Remissions and exacerbations of symptoms, arthralgia, pleurisy (pleural friction rub), anemia and mild thrombocytopenia, and positive ANA and anti-DNA antibodies all can occur with SLE.

How can SLE (systemic lupus erythematosus) cause such widespread tissue damage? What is the pathophysiology?

SLE is an autoimmune disease, with antibodies against selfantigens causing type ill hypersensitivity reactions and other autoimmune processes in many different body tissues.

Define: Immunologic homeostasis

Steady state of tolerance to self-antigens or lack of immune reaction against environmental antigens

DiGeorge syndrome involves deficient _______ lymphocyte immunity due to complete or partial lack of the _______ '

T; thymus

Delayed hypersensitivity reactions involve (B, T) lymphocytes, but not (B, T) lymphocytes.

T;B

Ayisha Walker, a 36-year-old woman studying medicine, has aching in her joints (arthralgia) and a new rash on her face. She states that the rash gets worse when she goes out into the sun. She also feels fatigued and gets a sharp pain in her chest when she breathes deeply. She has had "flare-ups" of these symptoms from time to time in the past, but this is the worst episode ever. Ms. Walker's diagnosis is systemic lupus erythematosus (SLE). What is the common descriptive term for Ms. Walker's facial rash?

The malar rash of SLE commonly is called a butterfly rash because it has the shape of a butterfly with extended wings.

Adolescent develops systemic anaphylaxis after being stung by a wasp. What type of hypersensitivity?

Type I (IgE-mediated)

Child develops systemic anaphylaxis after eating peanut butter. What type of hypersensitivity?

Type I (IgE-mediated)

Man develops hemolysis after mismatched blood transfusion. What type of hypersensitivity?

Type II (tissue-specific)

What is a type III hypersensitivity reaction?

Type III hypersensitivity is an immune complex-mediated reaction in which an antigen-antibody complex lodges in tissue, activating complement, and attracting phagocytes that cause tissue damage.

Man develops rejection of his transplanted heart. What type of hypersensitivity?

Type IV (cell-mediated)

Woman develops rash on legs from poison ivy after hiking in shorts.What type of hypersensitivity?

Type IV (cell-mediated)

"When immune complexes form, phagocytic cells are supposed to remove them," says a nurse. "Why does immune complex hypersensitivity occur instead?"

You are correct that phagocytic cells normally dispose of immune complexes when they form. However, in situations when immune complexes are of a certain intermediate size, they are not phagocytized as effectively. Those immune complexes are the ones that deposit in various tissues and cause type III, or immune complex-mediated, hypersensitivity reactions.

Antibodies can _______ target cell receptors, as in Graves disease; antibodies also can destroy or _______ receptors, as in myasthenia gravis.

activate; block

Cells in intact immunologically privileged sites have cell surface ligands that cause entering lymphocytes to undergo

apoptosis

In antibody-dependent cell-mediated cytotoxicity, target cells die by (necrosis, apoptosis).

apoptosis

Defective peripheral tolerance is a factor in development of (type II hypersensitivity, autoimmunity).

autoimmunity

Unusual or recurrent severe infections are common indicators of immune _______ ,

deficiency

Individuals with type 0 blood are universal (recipients, donors) because their RBCs have (no A and B antigens, both A and B antigens).

donors; no A and B antigens

Graft-versus-host disease occurs in graft recipients who are (immunocompetent, immunocompromised).

immunocompromised

Although type II hypersensitivity reactions can affect cells by several different mechanisms, they all involve antigens that are expressed in (many different, only specific) tissues.

only specific

Complement deficiencies often involve recurrent infections with encapsulated bacteria because C3b is an

opsonin

Autoimmunity occurs when the immune system reacts against _______ to such a degree that the person's own tissues are damaged by autoantibodies or autoreactive T cells.

self-antigens

Hypersensitivity reactions require _______ against a particular antigen that results in primary and secondary immune responses.

sensitization

An individual is (allergic, sensitized) when an adequate amount of antibodies or T cells is available to cause a noticeable reaction on reexposure to the antigen.

sensitized

The technical term for hives is _______ '

urticaria