Question 1

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

Accepted Answer

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

Question 2

A patient experiences hives and difficulty breathing within minutes after eating peanuts. Which treatment is most appropriate for this systemic anaphylactic reaction?

Accepted Answer

Administration of epinephrine

Question 3

Which of the following statements about desensitization therapy for allergies is correct?

Accepted Answer

It involves repeated injections of increasing doses of allergen to stimulate production of IgG blocking antibodies.

Question 4

A person with blood type O can safely donate blood to which of the following recipients?

Accepted Answer

All blood types (A, B, AB, O)

Question 5

Hemolytic disease of the newborn (HDNB) is most likely to occur under which of the following conditions?

Accepted Answer

An Rh– mother carries a second Rh+ fetus after being sensitized during a previous pregnancy.

Question 6

Which of the following best explains the mechanism of a Type III (immune complex) hypersensitivity reaction?

Accepted Answer

Immune complexes of antibodies and soluble antigens deposit in tissues, activating complement and attracting neutrophils, which release enzymes causing tissue damage.

Question 7

Which autoimmune disease is characterized by antibodies, T cells, and macrophages attacking the myelin sheath of nerves, leading to scar tissue formation?

Accepted Answer

Multiple sclerosis

Question 8

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

Accepted Answer

Insulin-dependent diabetes mellitus

Question 9

A transplant between genetically identical twins is called:

Accepted Answer

Isograft

Question 10

Which of the following best describes the role of the HLA complex in transplantation?

Accepted Answer

It encodes self-antigens that must be matched between donor and recipient to reduce transplant rejection.

Question 11

Which of the following is a limitation of the immune system's ability to eliminate cancer cells?

Accepted Answer

Tumor cells may lack antigenic epitopes or reproduce too rapidly for the immune system to respond.

Question 12

Which of the following is a characteristic of congenital immunodeficiencies?

Accepted Answer

They are caused by defective or missing genes present from birth.

Question 13

Which of the following best describes the attachment of HIV to a host cell?

Accepted Answer

The gp120 glycoprotein spike binds to the CD4 receptor and a coreceptor (CCR5 or CXCR4) on the host cell.

Question 14

Which of the following is a reason why HIV is difficult to eliminate from the body?

Accepted Answer

HIV can establish latent infection in memory T cells, serving as a reservoir.

Question 15

Which of the following drugs is a protease inhibitor used in the treatment of HIV?

Accepted Answer

Atazanavir

Question 16

A patient develops a red, blistering rash after contact with poison ivy. This is an example of which type of hypersensitivity reaction?

Accepted Answer

Type IV (delayed cell-mediated) hypersensitivity

Question 17

Which of the following is a real-world example of a disease caused by immune complex deposition in tissues?

Accepted Answer

Glomerulonephritis

Question 18

Which of the following best describes the function of a blocking antibody in allergy desensitization?

Accepted Answer

It binds to the allergen, preventing it from interacting with IgE on mast cells.

Question 19

Which of the following is a route of HIV transmission?

Accepted Answer

Contaminated needles

Disorders Associated with the Immune System: Hypersensitivity, Autoimmunity, Transplantation, Cancer, and Immunodeficiencies

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