Renal lesions in MRL mice.

Female MRL-Mp-lpr/lpr mice spontaneously develop autoimmune disease at three to five months of age and die most commonly from immune complex glomerulonephritis. Kidneys of two-month-old females appeared nearly normal by electron microscopy, and glomerular deposits of IgG an complement component 3 (C3) barely were detectable. In five-month-old females, immunofluorescence revealed numerous deposits of IgG and C3; glomerular mesangial cells were hypertrophic and hyperplastic and contained electron-dense material. There were subepithelial and subendothelial deposits of electron-dense material with swelling of epithelial cell cytoplasm. This disease has many features similar to the immune complex glomerulonephritis observed in New Zealand Black and White hybrid mice and in man.