Clinical significance of pretransplant chromosomally integrated human herpesvirus-6 in liver transplant recipients

Background. The clinical relevance of chromosomally integrated human herpesvirus-6 (CIHHV-6) after transplantation is not known. This study was aimed to determine the potential role of CIHHV-6 on the occurrence of other infections, allograft rejection, and outcomes after liver transplantation. Methods. A real-time quantitative human herpesvirus-6 (HHV-6) polymerase chain reaction assay was performed on whole blood samples of 548 liver transplant recipients. Clinical characteristics and outcomes of the patients with CIHHV-6 (defined as HHV-6 levels >1×10 genomes/mL) were compared with those of patients with low-level or no HHV-6 DNAemia. Results. Seven had CIHHV-6, 35 had low-level HHV-6 DNAemia, and 506 had no HHV-6 DNAemia before liver transplantation. Bacterial infection was significantly more common in the CIHHV-6 group compared with the group without HHV-6 (71.4% vs. 31.4%; P=0.04). A higher rate of allograft rejection was observed in the CIHHV-6 group compared with the group with low-level HHV-6 DNAemia (71.4% vs. 37.1%; P=0.12) and those without HHV-6 DNAemia (71.4% vs. 42.9%; P=0.25), although these differences did not reach statistical significance. Other opportunistic infections and outcomes were not significantly different between the CIHHV-6 group and the non-CIHHV-6 groups. Conclusion. Patients with CIHHV-6 may be at increased risk of indirect HHV6 effects after transplantation. This clinically relevant observation warrants confirmation using a larger cohort of transplant recipients.