Hypersensitivity

Question 1

List the 4 types of hypersensitivity reactions.

Answer 1

I: immediate / anaphylactic
II: antibody-mediated / cytotoxic
III: immune complex-mediated
IV: delayed / cell-mediated

Question 2

Which type of hypersensitivity reaction is dominated by IgE, mast cells, basophils, and eosinophils?

Answer 2

Type 1 / immediate / anaphylactic

Question 3

The PPD test is an example of which type of hypersensivitiy?

Answer 3

Type 4 / delayed / cell-mediated

Question 4

Hemolytic anemia following ABO mismatched blood transfusion is an example of which type of hypersensitivity?

Answer 4

Type 2 / antibody-mediated / cytotoxic

Question 5

The subcutaneous, perivascular Arthus reaction, which is characterized by neutrophil and complement activation, inflammation, and edema, is an example of which type of hypersensitivity?

Answer 5

Type 3 / immune complex-mediated

Question 6

Which types of hypersensitivity are most strongly associated with Th1 vs. Th2 CD4 T cells?

Answer 6

Th1: Type 4 / delayed / cell-mediated
Th2: Type 1 / immediate / anaphylactic
(although Th2 can also be seen in Type 4 for chronic asthma and other chronic allergies)

Question 7

Which type of hypersensitivity is seen in serum sickness vasculitis, and how long after exposure does it take to manifest?

Answer 7

Type 3 / immune complex-mediated; appears 7-10 days after exposure

Question 8

Contact hypersensitivity, such as to poison ivy or nickel ions, is an example of what type of hypersensitivity?

Answer 8

Type 4 / delayed / cell-mediated

Question 9

What kind of cells release tryptase, histamine, TNF-α, CCL3 chemokines like ECF-A, and leukotriene lipid activators like SRS-A in type 1 hypersensitivity reactions?

Answer 9

mast cells (when they degranulate)

Question 10

Describe the immediate vs. late phase for anaphylactic hypersensitivity reactions.

Answer 10

Immediate: occurs in minutes, wheal and flare, due to pre-formed mediators
Late: occurs 6-8 hours later, widespread swelling and inflammation due to cellular infiltration

Question 11

Farmer’s lung, or hypersensitivity pneumonitis, in the alveolar/capillary interface is an example of what type of hypersensitivity reaction?

Answer 11

Type 3 / immune complex-mediated

Question 12

What type of hypersensitivity is caused by antibody binding to cell surface receptors?

Answer 12

Type 2 / antibody-mediated / cytotoxic

Question 13

What type of hypersensitivty is responsible for the autoimmune diseases myasthenia gravis, Grave’s disease, Hashimoto’s disease, and insulin-resistant diabetes

Answer 13

Type 2 / antibody-mediated / cytotoxic

Question 14

What type of hypersensitivity is caused by a combination of IgG and complement-fixing soluble antigens, which together attract neutrophils that cause tissue damage?

Answer 14

Type 3 / immune complex-mediated

Question 15

Asthma, rhinitis, and allergic reactions such to food or bees are all what type of hypersensitivity reaction?

Answer 15

Type 1 / immediate / anaphylactic

Question 16

Lupus nephritis and post-strep glomerulonephritis are examples of what kind of hypersensitivity reaction?

Answer 16

Type 3 / immune complex-mediated

Question 17

What cells are stimulated and inhibited by TGF-β and IL-3?

Answer 17

Basophils increase, eosinophils decrease

Question 18

What cells are stimulated and inhibited by GM-CSF and IL-5?

Answer 18

Eosinophils increase, basophils decrease

Question 19

What is the most severe complication of anaphylaxis due to intravenous exposure, and what drug is used to treat this?

Answer 19

systemic anaphylaxis leading to hypotension; epinephrine

Question 20

Cell protein interactions with penicillin can produce abnormal antibodies that initiate inflammatory responses. What type of hypersensitivity reaction is this considered?

Answer 20

Type 2 / antibody-mediated / cytotoxic

Question 21

Celiac disease or gluten-sensitive enteropathy, which is mediated by the gliadin antigen, is an example of what type of hypersensitivity?

Answer 21

Type 4 / delayed / cell-mediated

Question 22

The Prausnitz-Kustner reaction for passive cutaneous anaphylaxis uses what type of hypersensitivity reaction?

Answer 22

Type 1 / immediate / anaphylactic

Question 23

What kind of cell is responsible for the release of chemokines, IFN-γ, TNF-α, LT (lymphotoxin) IL-3, and GM-CSF in cell-mediated hypersensitivity reactions?

Answer 23

Th1 cells

Question 24

Receiving too many tetanus boosters in <5 years, mouse-based antibodies, and snake venom antisera can all lead to antigen production followed by what type of hypersensitivity reaction?

Answer 24

Type 3 / immune complex-mediated

Question 25

Which hypersensitivity reactions can be treated by avoiding the allergens, giving anti-inflammatory drugs (like steroids), and inhibiting cytokines?

Answer 25

All 4 types

Question 26

Which hypersensitivity reactions can be treated by specifically targeting pathogenic B and T cells, blocking co-stimulatory molecules in the immune system, or inducing regulatory T-cell activity?

Answer 26

Types 2, 3, and 4

Question 27

Which hypersensitivity reactions can be treated by the humanized monoclonal omalizumab?

Answer 27

Type 1 - omalizumab is anti-IgE

Question 28

What hypothesis claims that the reason for increasing incidences of hypersensitivity in developed countries is due to less Th1 inducing infections, which protect against allergies?

Answer 28

The hygiene hypothesis

Question 29

What hypothesis claims that the reason for increasing incidences of hypersensitivity in developed countries is due to less infection-stimulated production of IL-10 and TGF-β, which downregulate both Th1 and Th2 activity?

Answer 29

The counter-regulation hypothesis