EXPRESSION OF THE HIGH-AFFINITY IgG RECEPTOR FcyRI AND TOLL-LIKE RECEPTOR 4 ON HUMAN MAST CELLS : INVOLVEMENT IN THE PATHOGENESIS OF CROHN'S DISEASE

Mast cells are major effector cells in allergic reactions, most of which are triggered by cross-linking of the high-affinity IgE receptor, FceRI. Recent studies in animal models indicate that mouse mast cells may also play a protective role in host defense and autoimmune diseases, most of which are mediated by FcγRIII or Toll-like receptors. However, the expression and function of FcyR and Toll-like receptors in human mast cells have not been thoroughly investigated. In this review article we present evidence showing that human mast cells express functional FcγRI and TLR4 on their surface, and that these receptors are upregulated by interferon-y. We discuss the roles of these receptors in the pathogenesis of Crohn's disease.