[Immunochemical studies in glomerulonephritis with mesangial immunoglobulin A precipitation].

Serum IgA, C3 and circulating immune complexes were examined in 20 patients with morphologically proved chronic glomerulonephritis with mesangial IgA precipitates and in 39 clinically healthy controls. The immune complexes were analyzed. 10 patients were with Berger's disease, 8 patients--with secondary IgA glomerulonephritis accompanying chronic liver disease and 1 patient was with Henoch-Schönlein's purpura. No significant differences were found between the mean values of IgA, C3 and the circulating immune complexes in the patients and the healthy controls as well as between the actively ill patients and those in remission. IgA and IgM in the immune complexes were significantly higher in the patients than in the healthy controls. IgA level in the immune complexes was significantly higher in the patients with active disease than in the patients in remission. In the patients with liver disease C3 and C4 often were not found in the immune complexes. In these patients it is possible that aggregates of immunoglobulins are found instead of immune complexes. The IgA level in the immune complexes could serve as a criterion for the disease activity.