Antigen-independent effects of immunoglobulin E.

Immunoglobulin E (IgE) is an important mediator in immediate hypersensitivity, as it facilitates mast cell degranulation and the release of immunomodulatory mediators, such as histamine, prostaglandins, and cytokines. Antigen-specific IgE is a hallmark of allergic diseases. Upon interaction with polyvalent antigen, IgE molecules crosslink and transmit signals that drive this process. Recently, an alternative function of IgE has come to light. Rather than merely priming the mast cell, in the absence of antigen, IgE influences mast cells, including their survival, receptor expression, and mediator release. The mechanisms by which IgE induces these effects and the biological consequences are being discovered and are showing that IgE has an important and active role in facilitating immune responses.