Detection of IgG subclasses with anti-IgE activity in patients with atopic diseases.

Significantly increased levels of IgG anti-IgE were seen in atopic patients as compared with controls. A correlation was observed between the levels of anti-IgE autoantibodies and serum IgE in the groups of atopic patients studied. No significant correlation was found between IgG anti-IgE levels and severity of the disease or between IgG subclasses with anti-IgE activity and clinical status. Analysis of IgG subclasses with anti-IgE activity showed that IgG1 and IgG4 were clearly factors in differentiating the atopics from the controls. IgG2 and IgG3 anti-IgE levels were not statistically significantly elevated. The lack of these autoantibodies may be explained by the presence of immune complexes or the lack of specificity of the monoclonal antibodies used in this study. These observations have not yet determined whether these autoantibodies and the isotypic selection and restriction observed play a role in the dysregulation of the immune response and in the evolution towards atopy.