Cytomegalovirus glomerulopathy and cytomegalovirus interstitial nephritis on sequential transplant kidney biopsies

Cytomegalovirus (CMV) nephropathy may be seen in kidney transplant biopsy specimens. We report a CMV-negative patient who received a kidney transplant from a CMV-positive donor and subsequently developed CMV glomerulopathy and CMV-associated interstitial nephritis, as observed in 2 sequential kidney biopsies. The first biopsy specimen showed CMV-positive endothelial cells in glomerular capillaries and CMV-infected monocytes in glomerular capillary lumens. The second biopsy specimen showed CMV-positive cells in the interstitium with associated lymphoplasmacytic infiltrate and tubular injury, but no evidence of direct CMV infection in tubular epithelial cells. Moreover, the second biopsy specimen showed persistent monocytes with cytoplasmic viral particles within glomerular capillary loops by electron microscopy. Our case shows that CMV glomerulopathy can be caused by direct CMV infection of glomerular capillary endothelial cells. CMV-positive circulating monocytes may play an important role in the different histopathologic manifestations of CMV nephropathy in kidney transplant grafts.