A new paradigm for immunoglobulin E in allergic diseases.

Recent observations at the level of the antigen presenting cell, as well as the T cell, point toward a pivotal role for interleukin (IL)-10 in the control of immunoglobulin E (IgE)-mediated allergic diseases, such as asthma and rhinitis. This has led to restructuring of the Th1/Th2 paradigm with IL-10 acting to modulate Th2-driven IgE antibody (Ab) responses. The modified Th2 response to cat allergen is associated with high-dose allergen exposure and the presence of high titer IgG and IgG4 Ab; however, IgE Ab and allergic symptoms are absent. Characteristics of this immune response indicate that it is a variant of the allergic response, which develops in an IL-10-dependent manner, but it is distinct from other types of nonallergic or tolerant responses. These observations point toward a new paradigm for the development of IgE-mediated responses. This may be important for advancing our understanding of the response to immunotherapy and anti-IgE, and for defining immune mechanisms that drive allergic responses.