IgE‐Containing Circulating Immune Complexes in Churg‐Strauss Vasculitis

Abstract
In 5 patients with vasculitis, hypereosinophilia and elevated serum IgE levels a diagnosis of Churg-Strauss syndrome was established. To identify a possible role of IgE in pathogenic mechanisms leading to the vasculitis, a sequential precipitation of the patients'' sera with different concentrations of polyethylene glycol (PEG) 6000 was performed. Using a radio immunosorbent test, the precipitates obtained for IgE were tested. Considerable amounts of IgE were traced in the serum precipitates of all patients, especially after the 2nd precipitation step (4.0% PEG). No IgE-containing precipitates were detectable in sera from patients with different allergic diseases and high IgE serum levels. Together with an increase in C3d serum levels and the failure to demonstrate C1q-binding material in patients'' sera, these data suggest the involvement of IgE-containing immune complexes in the pathogenesis of Churg-Strauss vasculitis, activating the complement via the alternate pathway.