Micro & Immunology · single question
What type of hypersensitivity reaction is Asthma (allergic/atopic asthma)?
Show answer and explanation
Correct answer: A. Type I (IgE-mediated)
A) Type I — CORRECT.
Allergic (extrinsic) asthma is a Type I (immediate) hypersensitivity reaction mediated by IgE antibodies on mast cells. Allergen exposure → IgE cross-linking → mast cell degranulation → histamine, leukotrienes, prostaglandins → bronchoconstriction, mucus production, airway inflammation.
B) Type II: Cytotoxic (e.g., hemolytic anemia, Goodpasture syndrome).
C) Type III: Immune complex deposition (e.g., lupus, serum sickness).
D) Type IV: Delayed cell-mediated (e.g., contact dermatitis, tuberculin test, Stevens-Johnson syndrome).
Allergic (extrinsic) asthma is a Type I (immediate) hypersensitivity reaction mediated by IgE antibodies on mast cells. Allergen exposure → IgE cross-linking → mast cell degranulation → histamine, leukotrienes, prostaglandins → bronchoconstriction, mucus production, airway inflammation.
B) Type II: Cytotoxic (e.g., hemolytic anemia, Goodpasture syndrome).
C) Type III: Immune complex deposition (e.g., lupus, serum sickness).
D) Type IV: Delayed cell-mediated (e.g., contact dermatitis, tuberculin test, Stevens-Johnson syndrome).
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