Mast cells are tissue-based inflammatory cells of hematopoietic
origin that respond to signals of innate and adaptive immunity
with immediate and delayed release of inflammatory mediators.
They are located primarily in association with blood vessels and
at epithelial surfaces. Mast cells are central to the pathogenesis of
diseases of immediate hypersensitivity and mastocytosis, but are
also implicated in host responses to pathogens, autoimmune
diseases, fibrosis, and wound healing.