Mast Cell Degranulation Type I — FRCA Primary MCQ

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EasyPhysiology - Endocrine & MetabolicMast Cell Degranulation Type IFRCA Primary

Regarding type 1 (immediate) hypersensitivity the cell that degranulates releasing histamine and other mediators is the:

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Correct answer: A — Mast cell

In Type I hypersensitivity: antigen cross-links IgE molecules bound to FcεRI receptors on mast cells and basophils triggering degranulation. Released mediators include: histamine / tryptase (mast cell specific — measured to confirm anaphylaxis) / leukotrienes / prostaglandins / and PAF. Tryptase peaks at 1-2 hours and should be measured at 1 / 6 / and 24 hours.

Reference: Power Kam 2018 Principles of Physiology for the Anaesthetist