Mast Cells and Basophils

Mast cells and basophils are key effector cells in allergic reactions. They play central roles in the initiation, propagation, and amplification of immediate hypersensitivity (allergic) responses. Both cell types are granulocytes that store potent inflammatory mediators (e.g., histamine, heparin) within cytoplasmic granules. Upon activation, typically by allergens cross-linking IgE bound to high-affinity FcεRI receptors on their surface, they rapidly degranulate, releasing these mediators into surrounding tissues or circulation. This process leads to classic symptoms of allergic reactions such as vasodilation, increased vascular permeability (edema), smooth muscle contraction (bronchoconstriction), mucus secretion, itching, and recruitment of other immune cells. Mast cells are tissue-resident cells, while basophils circulate in the bloodstream. While best known for their role in allergy/anaphylaxis, mast cells also participate in wound healing, defense against parasites/bacteria via pattern recognition receptors (PRRs), tissue remodeling, angiogenesis, and modulation of both innate/adaptive immunity. Basophils contribute similarly but are less abundant than mast cells.

Other names

Allergic Effector CellsTissue mast cellsCirculating basophils

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