[Detection of circulating immune complexes by the C1q complement fraction deviation test. 1st application in the study of human glomerulopathies].

The C1q deviation test measures the interference of circulating immune complexes in the fixation of radioactive C1q on target cells. The test was carried out in a large sample of cases of glomerular nephropathies, on the serum of patients with hypertension and on control sera. Positive results were frequently obtained with the sera of patients suffering from acute glomerulonephritis and membranous glomerulonephritis. Positive results were rarer in cases of minimal change discase and of membranoproliferative glomerulonephritis. These results suggest that the deviation of C1q in the serum of patients with various types of glomerulone phropathy may be due to circulating complexes but also to other substances. They indicate that efforts should be continued to isolate and biochemically identify the C1q binding substances in pathological sera.