Question 1

Which of the following best describes the difference between Type 1 and Type 3 hypersensitivity reactions?

Accepted Answer

Type 1 reactions are mediated by IgE and have an immediate onset, while Type 3 reactions are mediated by immune complexes (IgG, IgM, or IgA) and have a delayed onset.

Question 2

A patient receives a blood transfusion and develops fever, anemia, and jaundice. Laboratory tests reveal hemolysis of red blood cells. Which immunological mechanism is most likely responsible for this reaction?

Accepted Answer

Type 2 hypersensitivity, involving IgG or IgM antibodies binding to RBC antigens and activating the complement cascade.

Question 3

Which of the following is a plausible explanation for the increased prevalence of allergies in industrialized countries, according to the hygiene hypothesis?

Accepted Answer

Reduced exposure to microbes during childhood leads to insufficient immune system training, increasing susceptibility to allergies.

Question 4

A child is born with a genetic defect resulting in the absence of both B and T lymphocytes. Which disease does this child most likely have?

Accepted Answer

Severe combined immunodeficiency (SCID)

Question 5

A patient develops a butterfly-shaped rash across the nose and cheeks, kidney failure, and blood abnormalities. Laboratory tests reveal autoantibodies against multiple tissues. Which autoimmune disease is most likely?

Accepted Answer

Systemic lupus erythematosus

Question 6

Which of the following best explains the mechanism of molecular mimicry in the development of autoimmune diseases?

Accepted Answer

Microbial antigens resemble self-antigens, leading to cross-reactive immune responses against normal tissues.

Question 7

A patient with a history of allergies is prescribed epinephrine for emergency use. Which of the following best describes the physiological effect of epinephrine in anaphylaxis?

Accepted Answer

Epinephrine reverses airway constriction by causing bronchodilation and slows the release of allergic mediators.

Question 8

Which of the following is NOT a typical chemical mediator released by mast cells during a Type 1 hypersensitivity reaction?

Accepted Answer

Interleukin-2

Question 9

A patient develops inflammation at the site of a tuberculin skin test 36 hours after injection. Which type of hypersensitivity is this, and which immune cells are primarily responsible?

Accepted Answer

Type 4 hypersensitivity; T cells

Question 10

A newborn develops hemolytic disease due to maternal antibodies attacking fetal red blood cells. This occurs when the mother is Rh negative and the fetus is Rh positive. Which immunological principle does this illustrate?

Accepted Answer

Type 2 hypersensitivity involving IgG-mediated cell lysis

Question 11

Which of the following best describes the role of neutrophils in acute post-streptococcal glomerulonephritis (APSGN)?

Accepted Answer

Neutrophils are attracted to immune complexes deposited in the glomeruli, causing inflammation and tissue damage.

Question 12

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

Accepted Answer

Acquired Immunodeficiency Syndrome (AIDS) caused by HIV infection

Question 13

A patient with rheumatoid arthritis experiences joint pain and swelling. Which immunological process is primarily responsible for the joint damage?

Accepted Answer

Autoantibodies form immune complexes that activate phagocytes and stimulate cytokine release in the synovial membrane.

Question 14

Which of the following best explains why children with DiGeorge syndrome are at high risk for infections by fungi, protozoa, and viruses?

Accepted Answer

They lack cell-mediated immunity due to abnormal thymus development, resulting in deficient T cell function.

Question 15

Which of the following is the correct genotype for a person with blood type B in the ABO system?

Accepted Answer

$$BB or$$ $$BO$$

Question 16

A patient with multiple sclerosis (MS) experiences muscle weakness and vision problems. Which of the following best describes the immunological basis of MS?

Accepted Answer

Autoantibodies and T cells attack the myelin sheath surrounding nerve cells, impairing nerve impulse transmission.

Question 17

Which of the following is a primary immunodeficiency disease characterized by the absence of gamma globulin?

Accepted Answer

Agammaglobulinemia

Question 18

Which of the following best describes the universal donor and universal acceptor blood types?

Accepted Answer

Universal donor: type O; Universal acceptor: type AB

Question 19

A patient is diagnosed with Type 1 diabetes. Which of the following best explains the immunological mechanism underlying this disease?

Accepted Answer

Cytotoxic T cells attack insulin-producing beta cells in the pancreas, often triggered by molecular mimicry.

Question 20

Which of the following is a plausible consequence of drastic changes in the gut microbiome, according to current research?

Accepted Answer

Disruption of immune system training, increasing the risk of autoimmune diseases.

Disorders in Immunity: Hypersensitivities, Autoimmunity, and Immunodeficiencies

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