Mast Cells

Mast cells are long lived hematopoietic cells which are found throughout the body, often closely associated with blood vessels. In keeping with their role in host defense they are particularly prevalent at sites that interface with the environment such as the skin, airways and gastrointestinal tract. In the context of allergic disease, IgE-mediated mast cell activation leads to the release of preformed mediators such as histamine and proteases as well as the production of lipid mediators such as leukotriene C4 and prostaglandin D2. However, mast cells also produce multiple cytokines and chemokines which can have substantial immune impacts. These can be produced either in the context of degranulation or independently and selectively in response to a variety of stimuli including bacterial products, viral infection, and other microenvironmental triggers. Within the gastrointestinal tract mast cells have been implicated, not only in food allergy but also in several disorders associated with altered gut motility, epithelial barrier function, and inflammation. Mast cells are also known to be important in the regulation of angiogenesis and tissue remodeling with implications for a variety of intestinal disorders. Both animal models of mast cell deficiency and studies of human mast cells have helped to develop a better understanding of the role of these cells in host defense and disease in the gastrointestinal tract.