Solubilization of intraglomerular deposits of IgG immune complexes by human sera or gamma-globulin in patients with lupus nephritis.

A study of the solubilization of glomerular deposition of IgG immune complexes by sera from patients with lupus nephritis is described. Renal biopsy specimens were obtained from 11 patients with lupus nephritis, five patients with IgA nephropathy and one patient with minimal change nephrotic syndrome. These renal specimens were incubated with fresh, stored or heated sera from the same patients or healthy adults and human gamma-globulins at 37 degrees C for 1 h in plastic test tubes. The sections were stained with FITC conjugated heavy chain specific anti-human IgG or C3 antisera and then examined with a fluorescent microscope. The sections were also stained with FITC conjugated human gamma-globulins and rhodamine conjugated anti-human IgG, IgM or IgA antisera and then examined by double exposure under a fluorescent microscope. It was demonstrated that fresh human sera or gamma-globulins significantly solubilize glomerular immune deposits in patients with lupus nephritis in vitro. It was indicated that the solubilization of IgG glomerular deposits from patients with lupus nephritis does not depend on complement. It is postulated that solubilization of immune deposits in glomeruli requires the excess amounts of antigenic substances in patients with lupus nephritis.