Question 1

Which of the following best describes the mechanism of tissue injury in Type I hypersensitivity reactions?

Accepted Answer

IgE-mediated degranulation of mast cells and basophils, releasing inflammatory mediators

Question 2

A patient develops urticaria (hives) minutes after eating shellfish. Which immune mediator is primarily responsible for this reaction?

Accepted Answer

IgE

Question 3

Which of the following is a classic example of a Type II hypersensitivity reaction?

Accepted Answer

Hemolytic anemia following mismatched blood transfusion

Question 4

In Type III hypersensitivity, what is the main cause of tissue damage?

Accepted Answer

Deposition of antigen-antibody complexes in tissues, leading to complement activation and neutrophil recruitment

Question 5

Which of the following best explains the late-phase response in Type I hypersensitivity?

Accepted Answer

It involves recruitment of eosinophils, neutrophils, and lymphocytes by chemotactic factors, causing tissue damage hours after exposure

Question 6

A patient with myasthenia gravis has muscle weakness due to antibodies blocking acetylcholine receptors. This is an example of which hypersensitivity mechanism?

Accepted Answer

Antibody-mediated cellular dysfunction (Type II)

Question 7

Which of the following is a key difference between Type II and Type III hypersensitivity reactions?

Accepted Answer

Type II targets cell-bound antigens, while Type III involves soluble immune complexes

Question 8

A patient receives a penicillin injection and develops anaphylactic shock within minutes. What is the most appropriate immediate treatment?

Accepted Answer

Adrenaline (epinephrine) injection

Question 9

Which of the following diseases is most closely associated with Type IV hypersensitivity?

Accepted Answer

Contact dermatitis from poison ivy

Question 10

A patient develops chills, fever, rash, and joint pain one week after receiving a foreign antiserum. Laboratory tests reveal immune complex deposition in the kidneys. What is the most likely diagnosis?

Accepted Answer

Serum sickness (Type III hypersensitivity)

Question 11

Which of the following best describes the pathogenesis of the Mantoux test (tuberculin skin test)?

Accepted Answer

It is a delayed-type hypersensitivity reaction mediated by CD4+ T cells

Question 12

Which of the following is NOT a typical mediator or cell involved in Type I hypersensitivity?

Accepted Answer

Neutrophils

Question 13

A patient with systemic lupus erythematosus (SLE) develops glomerulonephritis due to immune complex deposition in the kidneys. Which hypersensitivity type is involved?

Accepted Answer

Type III

Question 14

Which of the following best explains why desensitization therapy can be effective for IgE-mediated allergies?

Accepted Answer

It gradually increases tolerance by repeated exposure to increasing doses of allergen, reducing IgE response

Question 15

Which of the following is a possible outcome of antibody binding to cell surface receptors without activating complement or Fc receptors?

Accepted Answer

Antibody-mediated cellular dysfunction

Question 16

A patient with a latex allergy develops redness and swelling at the site of contact 48 hours after exposure. Which immune cells are primarily responsible for this reaction?

Accepted Answer

CD4+ T cells and macrophages

Question 17

Which of the following best describes the mechanism of antibody-dependent cell-mediated cytotoxicity (ADCC) in Type II hypersensitivity?

Accepted Answer

Fc receptor-bearing cells bind to antibody-coated target cells, leading to cell lysis

Question 18

Which of the following is a distinguishing feature of Type IV hypersensitivity compared to the other types?

Accepted Answer

It is cell-mediated and does not involve antibodies

Question 19

A patient with Goodpasture's syndrome develops hematuria and pulmonary hemorrhage due to antibodies attacking the basement membrane in the kidneys and lungs. Which hypersensitivity type is this?

Accepted Answer

Type II

Question 20

Which of the following best explains why small circulating immune complexes in Type III hypersensitivity are less efficiently cleared by phagocytes?

Accepted Answer

They are less likely to be recognized and removed, leading to tissue deposition and inflammation

Hypersensitivity Reactions: Types, Mechanisms, and Clinical Examples

Guida di studio - Domande di pratica

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