Mast Cell Interleukin-2 Production Contributes to Suppression of Chronic Allergic Dermatitis

SummaryThe incidence of chronic allergic dermatitis is rapidly increasing. Regulatory control of this disease has not been adequately explored. Here we report that mast cell-derived interleukin-2 (IL-2) contributes to the suppression of chronic allergic dermatitis. Mice deficient in IL-2 production, or deficient in mast cells (KitW-sh/W-sh), showed exacerbated dermatitis upon repeated oxazolone challenge when compared to their wild-type counterparts. Adoptive transfer of wild-type, but not Il2-/-, mast cells into KitW-sh/W-sh mice dampened the inflammatory response. During the course of disease, mast cell expansion occurred at the site of inflammation and also in the spleen, where production of IL-2 by mast cells was markedly enhanced. In the absence of mast cell IL-2 production, the ratio of activated to regulatory T cells at the site of inflammation was increased. Thus, MC-derived IL-2 contributes to the maintenance of suppression in chronic allergic skin inflammation.

► Mast cells are suppressive in the late stages of chronic allergic dermatitis ► Mast cell-derived IL-2 is required for this suppression ► Mast cell IL-2 controls ratio of activated to regulatory T cells at site of inflammation