Hypersensitivity and Allergy

Question 1

What is the pathologic immune mechanism of type I hypersensitivity reactions?

Answer 1

IgE antibody, Th2 cells

Question 2

What are the mechanisms of tissue injury in type I hypersensitivity reactions?

Answer 2

Mast cells, eosinophils, and their mediators

Question 3

What is the pathologic immune mechanism of type II hypersensitivity reactions?

Answer 3

IgM, IgG antibodies against cell surface or extracellular matrix antigens

Question 4

What are the mechanisms of tissue injury in type II hypersensitivity reactions?

Answer 4

Opsonization and phagocytosis of cells
Complement- and Fc receptor-mediated recruitment and activation of leukocytes
Abnormalities in cellular functions, such as hormone receptor signaling or neurotransmitter blockade

Question 5

What is the pathologic immune mechanism of type III hypersensitivity reactions?

Answer 5

Immune complexes of circulating antigens and IgM or IgG antibodies

Question 6

What are the mechanisms of tissue injury in type III hypersensitivity reactions?

Answer 6

Deposition in blood vessel walls and tissues
Complement- and Fc receptor-mediated recruitment and activation of leukocytes

Question 7

What are the pathologic immune mechanism of type IV hypersensitivity reactions?

Answer 7

1. CD4+ T cells (Th1 and Th17 cells)
2. CD8+ CTLs

Question 8

What are the mechanisms of tissue injury in type IV hypersensitivity reactions?

Answer 8

1. Cytokine-meditated inflammation and macrophage activation
2. Direct target cell killing, cytokine-mediated inflammation

Question 9

What is the mechanism of type VIa hypersensitivity reactions?

Answer 9

Th1 cells, resulting in macrophage activation
(a = 1st letter of alphabet, Th1)

Question 10

What is the mechanism of type IVb hypersensitivity reactions?

Answer 10

Th2 cells, resulting in eosinophil and mast cell activation
(b = 2nd letter of alphabet, Th2)

Question 11

What are some examples of type IVa hypersensitivity reactions?

Answer 11

Maculopapular drug eruption, fixed drug eruption, poison ivy

Question 12

What is an example of a type IVb hypersensitivity reaction?

Answer 12

DRESS

Question 13

What is the mechanism of type IVc hypersensitivity reactions?

Answer 13

CTLs, granzymes, perforin
(c = cytotoxic)

Question 14

What is an example of a type IVc hypersensitivity reaction?

Answer 14

SJS/TEN

Question 15

What is the mechanism of type IVd hypersensitivity reactions?

Answer 15

Th17 cells, resulting in neutrophil activation

Question 16

What is an example of a type IVd hypersensitivity reaction?

Answer 16

AGEP, pustular psoriasis

Question 17

Which size complexes are more likely to be deposited in blood vessels?

Answer 17

Small immune complexes

Question 18

Which size complexes are more likely to be cleared by phagocytes?

Answer 18

Large immune complexes

Question 19

What is the target antigen in autoimmune hemolytic anemia?

Answer 19

erythrocyte membrane proteins

Question 20

What is the target antigen in autoimmune thrombocytopenic purpura?

Answer 20

platelet membrane proteins

Question 21

What is the target antigen in pemphigus vulgaris?

Answer 21

desmoglein

Question 22

What is the target antigen in ANCA vasculitis?

Answer 22

neutrophil cytoplasmic (granule) proteins

Question 23

What is the target antigen in Goodpasture syndrome?

Answer 23

basement membrane proteins in kidney and lung

Question 24

What is the target antigen in acute rheumatic fever?

Answer 24

streptococcal wall antigen that cross-reacts with myocardial antigen

Question 25

What is the target antigen in myasthenia gravis?

Answer 25

acetylcholine receptor on muscle

Question 26

What is the target antigen in Graves' disease?

Answer 26

thyroid stimulating hormone (TSH) receptor

Question 27

What is the target antigen in autoimmune pernicious anemia?

Answer 27

intrinsic factor secreted by gastric parietal cells and required for vitamin B12 absorption

Question 28

Which antigen(s) are involved in systemic lupus erythematous?

Answer 28

DNA, nuceloproteins

Question 29

Which antigen(s) are involved in polyarteritis nodosa?

Answer 29

In a minority of patients, hepatitis B virus surface antigen

Question 30

Which antigen(s) are involved in post-streptococcal glomerulonephritis?

Answer 30

Streptococcal cell wall antigens