Question 1

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

Accepted Answer

IgE antibodies bind to mast cells and basophils, causing degranulation and release of mediators such as histamine.

Question 2

A patient experiences hives and difficulty breathing minutes after eating peanuts. Which mediator is primarily responsible for the increased permeability of blood capillaries in this reaction?

Accepted Answer

Histamine

Question 3

Which equation represents the calculation of the probability of a child being born with hemolytic disease of the newborn (HDNB) if the mother is Rh- and the father is Rh+ (heterozygous)?

Accepted Answer

$$P(HDNB) = 0.5 	imes 1.0$$

Question 4

Which of the following is a key difference between systemic and localized anaphylaxis?

Accepted Answer

Systemic anaphylaxis may result in circulatory collapse and is treated with epinephrine, while localized anaphylaxis is typically limited to symptoms like hives and asthma.

Question 5

During a skin prick test for allergies, a wheal forms at the site of antigen inoculation. What does this indicate?

Accepted Answer

The patient has IgE-mediated hypersensitivity to the antigen.

Question 6

Which of the following best explains the role of desensitization therapy in preventing anaphylactic reactions?

Accepted Answer

It increases the production of IgG antibodies that intercept and neutralize antigens before they bind to IgE.

Question 7

A patient receives a blood transfusion and develops hemolysis. Laboratory tests show the presence of anti-A antibodies. Which blood type did the patient most likely receive?

Accepted Answer

Type A

Question 8

Which of the following equations correctly represents the formation of an immune complex in Type III hypersensitivity?

Accepted Answer

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

Question 9

Which autoimmune disease is characterized by antibodies, T-cells, and macrophages attacking the myelin sheath of nerves?

Accepted Answer

Multiple sclerosis

Question 10

Which of the following best describes the mechanism of delayed cell-mediated (Type IV) hypersensitivity?

Accepted Answer

T cells are sensitized by antigen presentation and, upon reexposure, release cytokines that cause tissue damage.

Question 11

Which of the following is an example of a cell-mediated autoimmune disease?

Accepted Answer

Insulin-dependent diabetes mellitus

Question 12

Which statement about the ABO blood group system is correct?

Accepted Answer

Type O individuals are universal donors because their RBCs lack A and B antigens.

Question 13

Which of the following best describes the process of tissue typing for organ transplantation?

Accepted Answer

Identifying and comparing HLAs using standardized antisera or monoclonal antibodies.

Question 14

Which type of graft uses tissue from a genetically identical twin?

Accepted Answer

Isograft

Question 15

Which of the following is a plausible consequence of a xenotransplantation product?

Accepted Answer

Hyperacute rejection due to response to nonhuman antigens.

Question 16

Which equation best represents the process of complement activation in cytotoxic hypersensitivity?

Accepted Answer

$$Ag_{cell} + Ab_{IgG/IgM} + C' \rightarrow Cell\ lysis$$

Question 17

Which of the following is a mechanism for self-tolerance in the immune system?

Accepted Answer

Ability to discriminate self from nonself and avoid immune response to self-antigens.

Question 18

Which autoimmune disease is characterized by immune complexes forming in the kidney glomeruli?

Accepted Answer

Systemic lupus erythematosus

Question 19

Which of the following best describes the role of embryonic stem cells (ESCs) in transplantation?

Accepted Answer

ESCs are pluripotent and can generate all types of cells for tissue and organ regeneration.

Disorders Associated with the Immune System (Chapter 19): Hypersensitivity, Autoimmunity, and Transplantation

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