Glomerular cell proliferation in human and experimental glomerulonephritis. Light- and electron-microscopical, and...

Three mitoses of endothelial glomerular cells have been observed by electron microscopy in 3 different nephropathies (a mixed membranous and proliferative glomerulonephritis, an intracapillary glomerulonephritis, and a mixed IgG-IgM cryoglobulinemia). Further light- and electron-microscopical and autoradiographic investigations on the occurrence and nature of the dividing cells responsible for glomerular hypercellularity in glomerulonephritis have been carried out in rats with an immunocomplex-induced glomerulonephritis. A statistically significant difference between treated and control animals have been found in the number of mitoses and DNA-synthesizing nuclei. All dividing glomerular cells observed by electron microscopy were endothelial. It is therefore proved that in glomerulonephritis an actual glomerular cell proliferation does occur; proliferating cells are suggested to be endothelial in nature.