Background: Renal allografts are a frequent site of subclinical cytomegalovirus (CMV) infection diagnosed by culture, but histologic inclusions occur in less than 1% of biopsies. The natural history of this subgroup of patients has been reported only occasionally, mostly before the availability of ganciclovir therapy.
Methods: We analyzed the clinical parameters and pathologic findings in 10 patients with CMV inclusions at allograft biopsy.
Results: The patients were 29-72 years old, and 9 of 10 (90%) had previous episodes of acute rejection, 3 of whom needed OKT3 administration. Histopathologic examination of the allografts showed interstitial inflammation with tubulitis in 7 of 10 (70%) patients; in 3 of 10 (30%) patients, viral inclusions were present in the glomerular capillary endothelia without any associated inflammatory response. Morphologic criteria for acute transplant glomerulopathy or proliferative glomerulonephritis were not satisfied. Extrarenal viral inclusions were documented in the gastrointestinal tracts of 2 of 10 (20%) patients. The patients were treated with reduced immunosuppression and ganciclovir. Five patients lost their grafts 56.6+/-86.6 days (range, 4-210 days; median, 21 days) after initial diagnosis. The serum creatinine in the remaining five patients was 3.3+/-2.0 mg/dl (range, 1.2-6.5 mg/dl; median, 2.5 mg/dl) 77+/-16 days (range, 56-101 days; median, 77 days) after transplantation. Histopathologic examination showed no residual viral inclusions in 5 of 7 (71.4%) follow-up specimens available for examination.
Conclusions: CMV inclusions in renal allograft biopsies typically occur after treatment for rejection. Ganciclovir eradicates replicative virus, but graft outcome is determined by coexisting acute rejection and chronic allograft nephropathy. Graft loss primarily attributable to CMV was not observed.