Hypersensitivity Reactions — NDEB AFK MCQ

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ModerateBiomedical SciencesHypersensitivity ReactionsNDEB AFK

In a type IV hypersensitivity reaction, which cells are primarily responsible for the immune response?

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Correct answer: D — T lymphocytes

Type IV (delayed-type) hypersensitivity is cell-mediated, driven by sensitised T lymphocytes (CD4+ helper T cells and CD8+ cytotoxic T cells). It occurs 48-72 hours after antigen exposure. Clinical examples in dentistry include contact allergy to nickel or latex. Types I, II, and III are antibody-mediated. Mast cells are central to type I (immediate) hypersensitivity.

Reference: Abbas – Cellular and Molecular Immunology, 10th ed., 2021