After using a cellular digestion technic to extract cells from the basement membranes of frozen kidney tissue, we used scanning electron microscopy to examine the acellular glomerular basement membranes (AGBM) and acellular tubular basement membranes (ATBM) from normal kidneys and from the kidneys of patients with lupus nephritis. This method revealed, in the AGBM, previously unrecognized three-dimensional patterns of pathologic changes. These patterns correlated with the World Health Organization (WHO) subclass of lupus nephritis and with the quantity of immune-complex deposition seen with two-dimensional microscopy. These pathologic changes included epimembranous, crater-like deformities with and without material resembling immune complexes; severely distorted, "moth-eaten" glomerular basement membrane; and the formation of secondary basement membrane within glomerular capillaries. We did not see similar abnormalities in the ATBM.