IgG anti-IgE in circulating immune complexes in the hyper-IgE syndrome.

We fractionated, by gel chromatography, sera with high IgE content from atopic subjects and five cases with the hyper-IgE syndrome, and measured the presence of IgE in high molecular weight (HMW) fractions. Two out of four asthmatics and four out of five hyper-IgE had HMW IgE. The same serum fractions gave positive results for conglutinin binding IgG (all six) and IgA (three cases) as well as C1q binding complexes (five cases). IgG auto-antibodies to IgE were also detected together with IgE in HMW fractions. Anti-F(ab)'2 activity was present in five cases (one of them negative for IgG anti-IgE). Our data indicate that complexes made of IgE and IgG anti-IgE are present mainly in patients with chronic allergic symptoms and most frequent in cases of hyper-IgE syndrome.