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 type of hypersensitivity reaction is this?

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 and joint pain several days after receiving a vaccine containing a non-human protein. Which hypersensitivity type is most likely involved?

Accepted Answer

Type III

Question 5

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

Accepted Answer

Contact dermatitis from poison ivy

Question 6

Which of the following is NOT a criterion for an effective vaccine?

Accepted Answer

Requires frequent high-dose boosters

Question 7

Which hypothesis suggests that autoimmunity may be triggered when T cells encounter self-antigens that are normally hidden from the immune system?

Accepted Answer

Hidden antigen hypothesis

Question 8

A woman who is Rh-negative gives birth to an Rh-positive baby. In a subsequent pregnancy with another Rh-positive fetus, the fetus develops hemolytic disease. What is the immunological basis for this condition?

Accepted Answer

Maternal IgG antibodies against Rh antigen cross the placenta and destroy fetal red blood cells.

Question 9

Which of the following best explains why autoimmune diseases are more common in the elderly?

Accepted Answer

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

Question 10

Which of the following is an example of molecular mimicry leading to autoimmunity?

Accepted Answer

A viral infection triggers T cells to attack host tissues due to similar antigens.

Question 11

Which cell type is primarily responsible for the tissue damage seen in Type IV hypersensitivity reactions?

Accepted Answer

Activated T cells

Question 12

A patient with systemic lupus erythematosus (SLE) experiences widespread inflammation due to immune complex deposition. Which hypersensitivity type is this?

Accepted Answer

Type III

Question 13

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

Accepted Answer

Type AB

Question 14

Which of the following is a plausible reason why women are more likely to develop autoimmune diseases than men?

Accepted Answer

Estrogen may enhance cytotoxic T cell activity against self-tissues.

Question 15

Which of the following best describes the time course and cellular mechanism of a tuberculin skin test reaction?

Accepted Answer

Delayed reaction (12–24 hours) mediated by T cells and macrophages

Question 16

Which of the following is NOT a cause of autoimmune disease according to current hypotheses?

Accepted Answer

Excessive production of IgE antibodies

Question 17

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

Accepted Answer

It neutralizes fetal Rh antigens before the mother can mount an immune response.

Question 18

Which of the following is a key difference between Type II and Type III hypersensitivity reactions?

Accepted Answer

Type II involves antibodies and complement targeting cells, while Type III involves immune complex deposition in tissues.

Question 19

A patient develops urticaria (hives) within minutes of eating peanuts. Which immune cells are primarily responsible for this reaction?

Accepted Answer

Mast cells and basophils

Question 20

Which of the following best describes the role of memory cells in hypersensitivity reactions?

Accepted Answer

They mediate faster and more severe responses upon re-exposure to the antigen.

Immune Disorders: Hypersensitivity and Autoimmunity

Study Guide - Practice Questions

Study Guide - Flashcards