Regulation of the low affinity ige fc receptor (CD23) in atopic dermatitis

Alterations in the production of CD23, the IgE Fc receptor, may play a role in the etiology of atopic dermatitis and other allergic conditions. Interleukin-4 (IL-4), interferon-γ (IFN-γ), and interferon-α (IFN-α) are involved in coor-dinate regulation of CD23. IL-4 stimulates production of both CD23 and IgE. IFN-γ also stimulates production of CD23, but suppresses production of IgE and inhibits IL-4-mediated production of CD23. IFN-α also suppresses these IL-4-mcdiated activities and, in addition, suppresses IFN-γ-mediated stimula-tion of CD23 production. Changes in this coordinate regulation may be in-volved in the development of atopic dermatitis. Expression of CD23 by Langerhans cells is stimulated by IL-4 and IFN-γ. Further, levels of CD23-positive T cells are elevated in atopic dermatitis subjects as compared to non-atopic controls, and observed skin changes appear to be related to changes in CD23- positive mononuclear cell populations. Coordinate regulation of CD23 by IFN-γ and IL-4 may also be important in other allergic conditions, parasitic infections, and a variety of disease states.