Question 1

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

Accepted Answer

IgE antibodies bound to mast cells and basophils are cross-linked by an antigen, leading to degranulation and release of mediators such as histamine.

Question 2

A patient experiences a severe drop in blood pressure and difficulty breathing within minutes after a bee sting. Which treatment is most appropriate for this condition?

Accepted Answer

Administration of epinephrine

Question 3

Which of the following statements about the hygiene hypothesis is correct?

Accepted Answer

It proposes that limiting exposure to pathogens may lower immune tolerance and increase hypersensitivity reactions.

Question 4

A child develops hives and gastrointestinal upset after eating peanuts. Which type of hypersensitivity reaction is this, and what is the primary antibody involved?

Accepted Answer

Type I (anaphylactic); IgE

Question 5

Which of the following best explains why RhoGAM is administered to Rh-negative mothers during and after pregnancy?

Accepted Answer

To prevent the mother from becoming sensitized to Rh antigens and producing anti-Rh antibodies

Question 6

Which of the following is a characteristic of Type III (immune complex) hypersensitivity reactions?

Accepted Answer

They result from immune complexes of antibodies and soluble antigens depositing in tissues, activating complement and causing inflammation.

Question 7

A patient develops a red, itchy rash after wearing a nickel bracelet. Which type of hypersensitivity reaction is this, and what is the underlying mechanism?

Accepted Answer

Type IV (delayed cell-mediated); T cell-mediated response to haptens bound to skin proteins

Question 8

Which autoimmune disease is characterized by autoantibodies, T cells, and macrophages attacking the myelin sheath of nerves, leading to neurological symptoms?

Accepted Answer

Multiple sclerosis

Question 9

Which of the following best describes the mechanism of action for cyclosporine in preventing transplant rejection?

Accepted Answer

It suppresses IL-2 production, disrupting cytotoxic T cell activation.

Question 10

A patient with DiGeorge syndrome is most likely to have which of the following immunological defects?

Accepted Answer

Absence of a thymus, resulting in failure to develop cell-mediated immunity

Question 11

Which of the following is a reason why developing an effective HIV vaccine is particularly challenging?

Accepted Answer

HIV frequently hides as a latent provirus, evading immune detection.

Question 12

Which of the following best describes the process by which HIV integrates into the host genome?

Accepted Answer

HIV RNA is reverse transcribed into DNA, which is then integrated into the host chromosome by integrase.

Question 13

Which of the following is the most common mode of HIV transmission worldwide?

Accepted Answer

Heterosexual contact

Question 14

A patient with rheumatoid arthritis has immune complexes of IgG, IgM, and complement deposited in the joints. Which type of hypersensitivity reaction is this?

Accepted Answer

Type III (immune complex)

Question 15

Which of the following best explains why 'GalSafe' pigs are less likely to provoke hyperacute rejection in xenotransplantation?

Accepted Answer

They are genetically modified to not express galactose on their cells, reducing recognition by human antibodies.

Question 16

Which of the following is a key feature of systemic lupus erythematosus (SLE)?

Accepted Answer

Autoantibodies against DNA and immune complex deposition in the kidneys

Question 17

Which of the following best describes the function of Highly Active Antiretroviral Therapy (HAART) in HIV treatment?

Accepted Answer

It uses multiple drugs to minimize the survival of resistant HIV strains.

Question 18

Which of the following is a real-life example of a Type II (cytotoxic) hypersensitivity reaction?

Accepted Answer

Hemolytic disease of the newborn due to Rh incompatibility

Question 19

Which of the following best explains why immune complexes cause tissue damage in Type III hypersensitivity reactions?

Accepted Answer

They activate complement, leading to inflammation and tissue injury.

Question 20

A patient with myasthenia gravis experiences muscle weakness due to which of the following mechanisms?

Accepted Answer

Antibodies blocking acetylcholine receptors at neuromuscular junctions

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

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