Monitoring of human cytomegalovirus, HHV-6 and HHV-7 infection in kidney transplant recipients by molecular methods to predict HCMV disease after transplantation: a prospective study.

Objectives: Recently, highly sensitive molecular assays to detect HCMV, HHV-6 and HHV-7 have been developed but their ability to detect patients at high risk for disease is unclear.
Methods: The positive predictive values (PPV) of pp65-antigenemia, quantitative plasma DNA and pp67-mRNA for CMV-disease were prospectively compared in 82 transplant recipients (72 renal, 10 pancreas-kidney) without CMV-prophylaxis. In addition, the prevalence of HHV-6 and HHV-7 infection were assessed using qualitative PCR. The assays were performed weekly.
Results: Three patients (3,7%) developed CMV-disease and were effectively treated. They were positive in all three CMV-assays. The PPVs of pp65-Ag, DNA viral load and pp67-mRNA were 33%, 20% and 25% in CMV-positive and 100%, 67% and 50% in seronegative recipients. Sensitivity and negative predictive value were 100% for all assays. Using cut-offs, PPVs were 75% (pp65-Ag > or = 20/200.000 cells) and 100% (PCR > or =30.000 copies/ml). Transfusion of >2 packed red cells, rejection and non-functioning graft were risk factors for CMV Five patients and one patient were positive for HHV-6 and HHV-7 resp.; both were symptomless and did not have a HCMV infection.
Conclusions: Therefore, pp65-antigenemia and plasma PCR with a cut-off could be useful for monitoring preemptive therapy.