The impact of cytomegalovirus disease and asymptomatic infection on acute renal allograft rejection

Cytomegalovirus (CMV) disease is a risk factor for allograft rejection in renal transplant (RTx) recipients. However, the role of asymptomatic CMV infection remains controversial. To determine the impact of CMV disease and asymptomatic infection on biopsy-proven acute rejection (BPAR) during 12 months post-RTx. A total of 106 consecutive RTx recipients at risk for CMV (donor and/or recipient CMV seropositive) were followed prospectively for 12 months post-RTx. CMV activity was monitored using nested PCR from whole blood. Three-month prophylaxis with valacyclovir or ganciclovir was given to 94 patients. BPAR episodes were classified according to the Banff 97 criteria. Multivariate Cox proportional hazards model was used to estimate the effect of CMV disease, asymptomatic infection, and other covariates on BPAR. Asymptomatic CMV infection occurred in 23% of the patients and 10% developed CMV disease. The incidence of BPAR was 29%. CMV disease was an independent risk factor for BPAR (HR = 3.0, P = 0.014), while asymptomatic CMV infection was not ( P = 0.987). In addition to CMV disease, expanded criteria donor and donor age were independent predictors for BPAR. In univariate analysis, valacyclovir (HR = 0.26, P = 0.008) decreased the risk of BPAR. A similar trend was observed with ganciclovir (HR = 0.42, P = 0.058). Only valacyclovir remained significant in multivariate analysis (HR = 0.18, P = 0.044). CMV disease, but not asymptomatic infection, is an independent risk factor for BPAR during the first 12 months post-RTx.