Segmental subepithelial deposits in primary glomerulonephritis: scanning electron microscopic examination of...

More accurate perception of the structural alterations in glomerular basement membrane (GBM) produced by subepithelial immune complex deposits is possible with a recently adapted technique that uses scanning electron microscopy of acellular material. With this procedure frozen tissue is treated sequentially by osmotic lysis, detergents, and DNase to solubilize both cellular components and immune complex deposits. Four patients with glomerulonephritis (acute postinfectious glomerulonephritis [one patient], segmental membranous glomerulonephritis [two patients], membranoproliferative glomerulonephritis, type III [one patient]) in whom segmental subepithelial deposits were found were studied by this technique; the resulting observations were correlated with the results of routine morphologic studies and a previous study of minimal change disease and diffuse membranous glomerulonephritis. Four types of structural alterations of the subepithelial GBM surface were observed. The differences in lesions observed in the various forms of glomerulonephritis are believed to be related to temporal, quantitative, and qualitative differences in immune complex-mediated glomerular injury.