IgG autoantibody to IgE in atopic patients.

An IgG type of antibody directed against IgE has been studied in serum from healthy and allergic individuals. The technique used is based on a solid phase paper radioimmunoassay in which the discs were sensitized with purified IgE myeloma. After incubation with patients' serum, human IgG labeled with iodine 125 was added. The anti-IgE antibodies were partially blocked by endogenous IgE in the serum and heating the serum samples at 56 degrees C disrupted the immune complexes (ie, IgG-aIgE:IgE), thereby increasing the detectable levels of IgG anti-IgE. The specificity of anti-IgE autoantibody was confirmed by both competitive inhibition and absorption experiments, using IgG, IgM, IgA, IgE, and rabbit anti-human IgG. Significantly raised levels of anti-IgE autoantibody were found in patients suffering from atopic disorders in comparison to the controls. These observations may suggest that the anti-IgE autoantibody could play a certain role in the modulation of IgE-mediated immune system and the pathogenesis of atopic diseases.