Lupus nephritis. Clinicopathology and immunopathology of 80 biopsy cases

The clinicopathology and immunopathology of 80 cases of lupus nephritis in a total of 1,187 biopsies were presented. Histologically, they consisted of 11 cases of mesangial lupus nephritis (13.8%), 51 cases of diffuse proliferative lupus nephritis (63.7%), and 18 cases of membranous lupus nephritis (22.5%). No cases of focal proliferative type, minimal changes or end-stage kidneys were included. Ten cases were male and they had no qualitative and quantitative differences with female ones in any respects. The microtubular structures were found in glomerular endothelial cells with a 70% frequency and in the interstitial endothelial cells with a 46% frequency. In the latter case, microtubular structures tended to be localized in the perinuclear space as well as in the endoplasmic reticulum. Spherical microparticles were found in 46% of all cases and the incidences were significantly higher in the membranous type. Organized deposits with straight parallel microfilaments were found only in a single case. Electron-dense deposits with fingerprint pattern were not seen. Immunohistochemically, various immunoglobulins, complement components, and fibrinogen were found deposited more frequently in diffuse proliferative lupus nephritis. IgG was the predominant immunoglobulin deposited in capillary loops in membranous types, and IgA in the mesangium in mesangial types. Extraglomerular deposition of immunoglobulins and complements were found in 26.3% of all cases.