Glomerular detection of schistosomal antigen by immunoelectron microscopy in human mansonian schistosomiasis

Schistosomal antigens (S. mansoni) were detected in glomeruli of nine patie nts with nephropathy and nephrotic syndrome by immunoelectron microscopy. T he criteria for patients' selection were presence of intestinal schistosomi asis and absence of any surgical or other medical diseases, particularly lu pus erythematosus, syphilis, and hepatitis B and C, which could explain the renal disease. When examined by light microscopy, kidney biopsies showed t ype I membranoproliferative glomerulonephritis in four patients, focal segm ental glomerulosclerosis in two, and mesangioproliferative glomerulonephrit is, membranous glomerulonephritis, and minimal change disease in one each o f the remaining three patients. Immunofluorescence showed mainly immunoglob ulin G (IgG), IgM, and different complement components (C3, C1q) deposits, particularly in the mesangial area, in eight patients. All patients had gol d-labeled schistosomal antigen deposits in their glomeruli, chiefly in mesa ngial cells and matrix, along the glomerular membrane, and occasionally in the cytoplasm of epithelial cells. Although membranous glomerulonephritis h as been rarely described in association with schistosomiasis and minimal ch ange disease may be occasionally caused by an infectious disease like syphi lis, the absence of definite experimental models and epidemiologic data sug gests that coincidental pathologies without causal relationship with schist osomiasis cannot be ruled our to explain these findings.