Expression of the cytomegalovirus genome in kidney allografts during active and latent infection.

Cytomegalovirus (CMV) infection is suggested to be a risk factor for chronic rejection. Here we investigated whether CMV can persist in renal allografts, and in which structures the viral genome is found during an acute infection and a latent period after an active infection. CMV infection was diagnosed in 72/157 patients by CMV antigenemia tests and by viral cultures. CMV antigens were demonstrated in 38 available biopsies by immunohistochemistry, and CMV genome by DNA hybridization in situ. Standard histology was also performed. CMV antigens were detected in 7/15 biopsies obtained during acute infection, in three with acute rejection, and chronic changes in the other biopsies. CMV genome was located in inflammatory cells, in tubuli and in the capillary endothelium. During a latent period without a positive finding in blood or urine, CMV antigens were still found in 6/31 biopsies. CMV DNA was found in inflammatory cells, tubular and glomerular structures and in the endothelium of the arterioles. During the latent period with persistent CMV in the graft, in most cases (10/12) mild to moderate chronic changes were recorded.