Immune complex diseases. I. Pathological changes in the kidneys of BALB-c mice neonatally infected with Moloney leukaemogenic and murine sarcoma viruses.

The pathological alterations in renal glomeruli of BALB/c mice infected neonatally or by vertical transmission from the mother with Moloney leukaemogenic virus or mouse sarcoma virus have been studied by light microscopy, immunofluorescence and electron microscopy. The abnormalities observed by light microscopy were an initial proliferation of mesangial, endothelial and epithelial cells, followed by thickening and deposition of PAS-positive material in the basement membrane, localized necrosis and a variable degree of glomerulosclerosis, with the overall characteristics of a chronic, proliferative glomerulonephritis. The abnormalities were more severe when leukaemia became manifest. By electron microscopy few alterations were noted in the early stages, mainly a marked swelling and reticulation of the endothelial cells of some animals, and in stages of intermediate severity thickening of the mesangial area and of the basement membrane with local formation of subepithelial projections and fusion of the foot processes of the epithelial cells. Only a few virus particles were occasionally detected in some glomeruli. Immunoglobulin and viral antigens were demonstrated in practically all glomeruli by immunofluorescence and antibody capable of neutralizing MLV was eluted from the kidney of the infected mice. These findings appear to be consistent with an immune complex aetiology of this glomerular disease.