Question 1

Which of the following best describes the mechanism of Type I (immediate) hypersensitivity reactions?

Accepted Answer

IgE antibodies bind to mast cells and basophils, causing degranulation and release of inflammatory mediators upon allergen exposure.

Question 2

A patient receives a blood transfusion with incompatible blood and develops hemolysis. Which hypersensitivity type is responsible?

Accepted Answer

Type II (Cytotoxic hypersensitivity)

Question 3

Which of the following is a key characteristic of Type III hypersensitivity reactions?

Accepted Answer

Formation and deposition of antigen-antibody complexes in tissues

Question 4

A child develops a rash 48 hours after contact with poison ivy. Which hypersensitivity type is this, and what is the main cell type involved?

Accepted Answer

Type IV; Activated T cells

Question 5

Which of the following is NOT a proposed hypothesis for the development of autoimmune diseases?

Accepted Answer

Excessive production of IgE antibodies

Question 6

Which of the following best explains why RhoGAM is administered to Rh-negative mothers?

Accepted Answer

To prevent the mother's immune system from attacking fetal red blood cells in subsequent pregnancies

Question 7

Which of the following is a real-world example of a Type IV hypersensitivity reaction?

Accepted Answer

Tuberculin skin test reaction

Question 8

Which of the following blood types can safely receive blood from any donor?

Accepted Answer

Type AB

Question 9

Which immune cell is primarily responsible for the cytotoxic effects seen in Type II hypersensitivity reactions?

Accepted Answer

Plasma cells producing IgG or IgM

Question 10

A patient with systemic lupus erythematosus (SLE) experiences widespread tissue inflammation. Which hypersensitivity mechanism is most likely involved?

Accepted Answer

Type III hypersensitivity

Question 11

Which of the following is a criterion for an effective vaccine?

Accepted Answer

It should induce a strong memory response

Question 12

Which of the following best describes molecular mimicry as a cause of autoimmunity?

Accepted Answer

A pathogen shares structural similarities with host antigens, leading to cross-reactive immune responses

Question 13

Which of the following equations best represents the relationship between antigen-antibody complex formation and hypersensitivity reactions?

Accepted Answer

$$Ag + Ab \rightarrow AgAb_{complex}$$

Question 14

Which hypersensitivity type is most likely to be involved in the rejection of a transplanted organ several days after transplantation?

Accepted Answer

Type IV

Question 15

Which of the following is a plausible reason why autoimmune diseases are more common in the elderly?

Accepted Answer

Immune regulation mechanisms decline, increasing the risk of self-reactivity

Question 16

Which of the following best describes the time course and main cell type involved in Type IV hypersensitivity?

Accepted Answer

Several days; Activated T cells

Question 17

A patient develops glomerulonephritis after a streptococcal infection. Which hypersensitivity type is most likely responsible?

Accepted Answer

Type III

Question 18

Which of the following is a common misconception about the causes of autoimmune diseases?

Accepted Answer

They are always caused by viral infections

Question 19

Which of the following best explains why a person with type O blood is considered a universal donor?

Accepted Answer

Type O blood lacks A and B antigens, so it is not recognized as foreign by recipients with other blood types

Immune Disorders: Hypersensitivity and Autoimmunity

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