Question 1

Which of the following best describes the mechanism underlying a Type I hypersensitivity reaction, such as hay fever or anaphylaxis?

Accepted Answer

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

Question 2

A patient receives a blood transfusion and develops fever, hemolysis, and jaundice. Which hypersensitivity type is most likely responsible for these symptoms?

Accepted Answer

Type II (Antibody-mediated cytotoxic)

Question 3

Which chemical mediator released from mast cells is primarily responsible for the vasodilation and increased vascular permeability seen in allergic reactions?

Accepted Answer

Histamine

Question 4

A child is born with a genetic defect resulting in the absence of T cells. Which syndrome is most likely?

Accepted Answer

DiGeorge syndrome

Question 5

Which blood type is considered the universal donor, and why?

Accepted Answer

Type O, because it lacks A and B antigens on erythrocytes.

Question 6

A positive tuberculin skin test is an example of which type of hypersensitivity?

Accepted Answer

Type IV (Delayed cell-mediated)

Question 7

Which autoimmune disease is characterized by autoantibodies against acetylcholine receptors at the neuromuscular junction?

Accepted Answer

Myasthenia gravis

Question 8

What is the most common infection-induced immunodeficiency disease worldwide?

Accepted Answer

AIDS (caused by HIV)

Question 9

Which of the following best explains the hygiene hypothesis in relation to allergy development?

Accepted Answer

Reduced early-life exposure to microbes leads to an undertrained immune system and increased allergies.

Question 10

A patient develops glomerulonephritis several weeks after a streptococcal skin infection. Which immunological mechanism is most likely involved?

Accepted Answer

Deposition of immune complexes in the kidney, activating complement and attracting neutrophils.

Question 11

Which formula correctly represents the possible genotypes for blood type A in the ABO system?

Accepted Answer

$$AA$$ and $$AO$$

Question 12

A patient with systemic lupus erythematosus (SLE) produces autoantibodies against which of the following?

Accepted Answer

A wide variety of organs, tissues, and intracellular materials

Question 13

Which of the following is a plausible outcome of transfusing the wrong blood type?

Accepted Answer

Massive hemolysis, systemic shock, and kidney failure

Question 14

Which type of hypersensitivity is most likely involved in contact dermatitis from poison ivy exposure?

Accepted Answer

Type IV (Delayed cell-mediated)

Question 15

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

Accepted Answer

Microbial antigens resemble human cell markers, leading to cross-reactive antibodies.

Question 16

Which of the following is NOT a typical symptom of systemic lupus erythematosus (SLE)?

Accepted Answer

Overproduction of thyroxin

Question 17

Which of the following is a primary immunodeficiency disease present at birth due to genetic errors?

Accepted Answer

Severe combined immunodeficiency (SCID)

Question 18

Which of the following best explains why children delivered by cesarean section have a higher risk of developing food allergies?

Accepted Answer

They are not exposed to vaginal and stool bacteria that help train the immune system.

Question 19

Which of the following equations correctly represents the inheritance of Rh factor?

Accepted Answer

$$Rh^+ =$$ dominant, $$Rh^- =$$ recessive$

Disorders in Immunity: Hypersensitivity, Autoimmunity, and Immunodeficiency

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