Q: Which equation correctly represents the formation of an immune complex in a Type III hypersensitivity reaction?

$$ \text{Ag} + \text{Ab} \rightarrow \text{Ag-Ab complex} $$

Question 1

Which of the following best distinguishes primary from secondary immunodeficiencies?

Accepted Answer

Primary immunodeficiencies result from inherited genetic defects, while secondary immunodeficiencies are caused by external factors such as infections or medications.

Question 2

Which of the following is NOT a common cause of secondary immunodeficiency?

Accepted Answer

Congenital absence of the thymus

Question 3

Which statement best explains why cancer can be considered a failure of the immune system?

Accepted Answer

The immune system fails to recognize and destroy abnormal cells, allowing them to proliferate.

Question 4

Which of the following is an example of a primary immunodeficiency?

Accepted Answer

Severe Combined Immunodeficiency (SCID)

Question 5

A patient develops hives and difficulty breathing minutes after eating peanuts. This is best classified as which type of hypersensitivity reaction?

Accepted Answer

Type I (Immediate, IgE-mediated) hypersensitivity

Question 6

Which of the following best describes the mechanism of Type II hypersensitivity reactions?

Accepted Answer

Antibodies bind to cell surface antigens, leading to cell destruction via complement activation or phagocytosis.

Question 7

Which equation correctly represents the formation of an immune complex in a Type III hypersensitivity reaction?

Accepted Answer

$$ 	ext{Ag} + 	ext{Ab} ightarrow 	ext{Ag-Ab complex} $$

Question 8

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

Accepted Answer

Hemolytic disease of the newborn (Rh incompatibility)

Question 9

A patient receives a mismatched blood transfusion and develops hemolysis. Which hypersensitivity type is involved?

Accepted Answer

Type II

Question 10

Which of the following best describes the difference between Type III and Type II hypersensitivity reactions?

Accepted Answer

Type III involves immune complexes depositing in tissues, while Type II involves antibodies binding to cell surface antigens.

Question 11

Which of the following is a classic example of a Type IV (delayed, T-cell mediated) hypersensitivity reaction?

Accepted Answer

Contact dermatitis from nickel exposure

Question 12

Which of the following best explains the pathogenesis of graft-versus-host disease (GVHD)?

Accepted Answer

Donor T cells attack recipient tissues, recognizing them as foreign.

Question 13

Which of the following is a key feature of Type I hypersensitivity reactions?

Accepted Answer

IgE-mediated degranulation of mast cells

Question 14

Which of the following is a common clinical manifestation of Type III hypersensitivity?

Accepted Answer

Glomerulonephritis

Question 15

Which of the following equations best represents the complement activation pathway in Type II hypersensitivity?

Accepted Answer

$$ 	ext{Ab} + 	ext{Cell surface antigen} ightarrow 	ext{Complement activation} ightarrow 	ext{Cell lysis} $$

Question 16

A patient develops a rash 48 hours after exposure to a new medication. Which hypersensitivity type is most likely responsible?

Accepted Answer

Type IV

Question 17

Which of the following is a mechanism by which allergens trigger an immune response in Type I hypersensitivity?

Accepted Answer

Allergens cross-link IgE antibodies on mast cells, leading to degranulation.

Question 18

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

Accepted Answer

Systemic lupus erythematosus (SLE)

Question 19

Which of the following best describes the role of T cells in Type IV hypersensitivity reactions?

Accepted Answer

T cells release cytokines that recruit macrophages and cause tissue damage.

Question 20

Which of the following is a potential consequence of transplant rejection?

Accepted Answer

Destruction of the transplanted organ by recipient immune cells

Immunodeficiencies, Hypersensitivities, and Transplant Immunology: Study Notes

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