Background: Reactivation of human herpesvirus (HHV)-6 and HHV-7 has been linked to various posttransplant adverse events through immunomodulatory effects. The potential utility of monitoring for HHV-6 and HHV-7 viremia remains unclear.
Methods: In this clinical trial, 129 liver transplant recipients were randomized to be monitored in real-time for HHV-6 and HHV-7 viremia by polymerase chain reaction at regular intervals from 0 to 12 weeks after transplantation ("monitoring" group) or to undergo usual care ("no-monitoring" group). Therapeutic intervention for a positive polymerase chain reaction result included reduction in immunosuppression and preemptive antiviral therapy, at the discretion of the attending team. The primary outcome was a composite of adverse events indirectly attributable to viral reactivation (including opportunistic infection, graft rejection and severe hepatitis C virus recurrence).
Results: In the "monitoring" group, HHV-6 and HHV-7 viremia occurred in 23 of 64 patients (35.9%) and 21 of 64 patients (32.8%) patients, respectively. We found no cases of symptomatic HHV-6 and HHV-7 disease. Some therapeutic interventions were performed in 59.1% of viremic episodes. There were no differences in cumulative incidence of the primary outcome between the "monitoring" and "no-monitoring" groups at 1 year (58.7% vs. 52.3%; odds ratio, 0.77; 95% confidence interval, 0.38-1.55) or at 5 years after transplantation (79.0% vs. 70.3%; odds ratio, 0.63; 95% confidence interval, 0.28-1.42). However, we found a trend toward a lower incidence of graft rejection at year 1 in the "monitoring" group (30.2% vs. 44.6%; P=0.091).
Conclusion: In this first trial, no benefit could be demonstrated from routine monitoring of HHV-6 and HHV-7 viremia in graft or patient outcome after liver transplantation.
Trial registration: ClinicalTrials.gov NCT00242099.