[Circulating immune complexes and in vivo fixation of immunoglobulin G, A and C3 onto hepatocytes in patients with Crohn's disease (author's transl)].

In vivo fixation of immunoglobulin and C3 onto the hepatocellular membrane of patients with Crohn's disease was studied by immunofluorescence. IgG binding was observed in 93% of patients with disease activity but not in patients without disease activity. C3 binding was present in 21% of patients with active disease. IgA binding was found in approximately one half of all patients with Crohn's disease irrespective of disease activity. The immunoglobulin and C3 binding to hepatocytes was not correlated with histopathological findings. Circulating immune complexes were detected with the Raji cell assay in approximately one half of all patients with Crohn's disease and showed no correlation to disease activity. The following conclusions can be derived from these studies: 1. The in vivo fixed IgG represents immune complexes, which is eliminated by the liver as part of the physiological clearance function. 2. These aggregates bind to hepatocytes predominantly via IgGFc receptors. 3. Hepatocellular bound IgG and C3 show no correlation to histopathological liver alterations. 4. In vivo bound hepatocellular IgG aggregates have different properties than the immune complexes detected by the Raji cell assay.