Development of a lesion resembling diabetic nephropathy in a renal homograft

One month following a cadaver renal transplant for obstructive uropathy, a 27-year-old man developed diabetes mellitus. Two years later, marked proteinuria and decreased renal function were detected. Eight months later, a second decline in function occurred. Light microscopy of graft biopsy specimens obtained after each decline in renal function showed increased mesangial cells and matrix, thickening of Bowman capsule, and tubular atrophy with basement membrane thickening. Vascular changes, interstitial infiltrate, and fibrosis were not prominent. Electron microscopic studies of the second biopsy specimen confirmed the light microscopic changes; subepithelial dense deposits were also detected. Immunofluorescent studies of both biopsy specimens demonstrated linear staining of glomerular and tubular basement membranes and Bowman capsule for IgG and albumin. Antikidney antibodies were not detected in the patient's serum. These observations suggest development of the diffuse form of diabetic nephropathy in a renal homograft following steroid-induced diabetes mellitus.