Circulating immune complexes in nephritis.

Serum samples from 115 patients with various kidney disease were studied by means of precipitation in 3.5% polyethylene-glycol (the PEG test) and by inhibition of agglutination of IgG-coated polystyrene particles induced by C1q, two tests developed for the detection of circulating immune complexes. Positive results were found in acute glomerulonephritis, particularly in its early stages, and also in chronic forms of glomerulonephritis: membranous, focal sclerosing, mesangiocapillary and focal glomerulonephritis. High levels of circulating immune complexes were found in lupus nephritis. In most cases the test results showed a good correlation with the clinical course of the diseases.