[Immune complexes in allergies: evidence of IgE-containing immune complexes in Churg-Strauss vasculitis].

In five patients with vasculitis, hypereosinophilia and elevated serum-IgE levels, the diagnosis of Churg-Strauss syndrome was established. To identify a possible role of IgE in pathogenic mechanisms leading to vasculitis, a sequential precipitation of patients' sera was performed using various concentrations of polyethylene glycol 6000 (PEG). Using a radioimmunosorbent test, the precipitates obtained were tested for their IgE contents. Considerable amounts of IgE were found in the serum precipitates of all patients. In parallel studies, no IgE-containing precipitates were detected in sera from patients with different allergic diseases and high IgE serum levels. The demonstration of IgE-containing PEG precipitable material in all patients suffering from Churg-Strauss syndrome, together with the finding of an elevated C3d and C4 level and a decreased C3 level in one patient and an increased C3d level in a second patient, suggests that IgE-containing immune complexes play a pathogenic role in the Churg-Strauss syndrome.