[Regulation of immunoglobulin E synthesis].

Immunoglobulin E plays a central role in the pathogenesis of allergic diseases. Therefore an understanding of mechanisms which regulate production of IgE is very important. Recent studies have demonstrated that the induction of IgE synthesis in B cells requires two signals. The first one, IgE isotype-specific, is delivered by interleukins 4 or 13 and results in epsilon germ line transcription. The second B-cell-activating factor is responsible for switch recombination and expression of mature epsilon RNA transcripts. This signal is delivered by lymphocytes T, but these cells can be replaced by Epstein-Barr virus infection, protein gp39 (CD40L), monoclonal antibodies to CD40 and CD58, membrane-TNF-alpha, as well as corticosteroids. Besides this a variety of factors can modulate the IgE synthesis. Interleukin-2, -5, -6, -9, -10, MIP1-alpha, RANTES and sCD23 enhance the production of IgE whereas PAF, PGE2, IL-8, -12 and 18, IFN-alpha and gamma, TGF-beta, sIL-4R, IL-1Ra, and probably sIL-1R inhibit it. In this article, we review current knowledge about the mechanisms underlying the synthesis of IgE in humans, including molecular events and clinical attempts at reduction of the total IgE level in patients with allergic diseases.