Q: Which equation best represents the agglutination reaction during a transfusion mismatch?

$$\text{Antigen} + \text{Antibody} \rightarrow \text{Agglutination}$$

Q: Which equation best represents the formation of immune complexes in Type III hypersensitivity?

$$\text{Antigen} + \text{Antibody} \rightarrow \text{Immune Complex}$$

Question 1

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

Accepted Answer

Antibody (such as IgE) on sensitized cells’ membranes binds antigen, causing degranulation and release of inflammatory mediators.

Question 2

A patient experiences acute anaphylaxis after a bee sting. Which molecule is primarily responsible for the rapid onset of symptoms?

Accepted Answer

Histamine

Question 3

Which cell type is most directly involved in the degranulation process during an allergic reaction?

Accepted Answer

Mast cells

Question 4

A person with blood type O is considered a universal donor. Why is this the case?

Accepted Answer

Type O blood contains no antigens, so it does not trigger an immune response in recipients.

Question 5

Which equation best represents the agglutination reaction during a transfusion mismatch?

Accepted Answer

$$	ext{Antigen} + 	ext{Antibody} ightarrow 	ext{Agglutination}$$

Question 6

A Rh-negative woman is pregnant with a Rh-positive fetus. What is the risk in subsequent pregnancies if untreated?

Accepted Answer

The mother will develop antibodies against the fetus’s Rh antigen, leading to hemolytic disease of the newborn.

Question 7

Which hypersensitivity type is most associated with immune complex deposition in tissues, such as in glomerulonephritis?

Accepted Answer

Type III (Immune Complex–Mediated)

Question 8

A patient with systemic lupus erythematosus (SLE) produces autoantibodies against DNA. What is the consequence of these autoantibodies?

Accepted Answer

Formation of immune complexes that deposit in tissues, causing inflammation.

Question 9

Which of the following is a characteristic feature of Type IV (Delayed or Cell-Mediated) hypersensitivity?

Accepted Answer

Inflammation occurs 12–24 hours after contact with antigen, mediated by T cells.

Question 10

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

Accepted Answer

Type IV (Delayed or Cell-Mediated)

Question 11

Which immunosuppressive drug class acts by blocking T cell responses?

Accepted Answer

Cyclosporine

Question 12

A patient develops intensely irritating skin rash after exposure to poison ivy. Which hypersensitivity type is involved?

Accepted Answer

Type IV (Delayed or Cell-Mediated)

Question 13

Which equation best represents the formation of immune complexes in Type III hypersensitivity?

Accepted Answer

$$	ext{Antigen} + 	ext{Antibody} ightarrow 	ext{Immune Complex}$$

Question 14

Which of the following is NOT a plausible cause of autoimmune diseases?

Accepted Answer

Excess production of histamine by mast cells.

Question 15

A patient with Bruton-type agammaglobulinemia is stung by a bee and exposed to poison ivy. Which hypersensitivity reaction is he LEAST likely to experience?

Accepted Answer

Type I (Immediate) hypersensitivity to bee venom.

Question 16

Which equation best represents the effect of epinephrine in treating anaphylactic shock?

Accepted Answer

$$	ext{Epinephrine} ightarrow 	ext{Relaxation of smooth muscle} + 	ext{Reduced vascular permeability}$$

Question 17

Which of the following is a primary immunodeficiency disease characterized by a lack of T cells and B cells?

Accepted Answer

Severe combined immunodeficiency disease (SCID)

Question 18

Which equation best represents the effect of glucocorticoids in transplantation?

Accepted Answer

$$	ext{Glucocorticoids} ightarrow 	ext{Anti-inflammatory} + 	ext{Kill T cells}$$

Question 19

Which of the following is a systemic autoimmune disease characterized by autoantibodies against DNA and a facial rash?

Accepted Answer

Systemic lupus erythematosus (SLE)

Immune Disorders: Hypersensitivities, Autoimmunity, and Immunodeficiency

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