Exposing the mast cell: its novel integrated role in allergy

New discoveries have suggested that the mast cell has the potential to regulate allergic inflammation by inducing IgE synthesis from B cells. Under allergic inflammatory conditions, "primed" mast cells appear to express higher levels of the high affinity receptor for IgE and the ligand for the surface antigen CD40, involved in T/B cell interactions leading to immunoglobulin production, as well as Th2-type cytokines, IL-4 and IL-13. The critical role of these cells in the induction of IgE synthesis is supported by the findings that anti-ligand for the surface antigen CD40, anti-IL-4, and anti-IL-13 monoclonal antibodies inhibit IgE production. Mast cells also have the potential to function as antigen presenting cells with the ability to shift T cells into Th2 subtypes. These recent findings suggest that mast cells can modulate important regulatory functions of the allergic response by acting directly on B cells and inducing IgE production.