Human herpesvirus-6 is associated with cytomegalovirus reactivation in liver transplant recipients.

Human herpesvirus-6 (HHV-6) may be a risk factor for cytomegalovirus (CMV) disease in posttransplant patients, possibly through a direct interaction or through a general immunomodulatory effect. To examine this possibility, 88 liver transplant recipients were monitored with serial HHV-6 polymerase chain reaction (PCR), CMV antigenemia, and CMV plasma viral load. HHV-6 infection was defined by a positive PCR of peripheral blood lymphocytes. Forty-eight (54.4%) of 88 patients had at least 1 positive HHV-6 PCR. CMV recurrence was significantly more common in patients with HHV-6 infection (38/48 patients [79. 2%]), compared with recurrence in those without HHV-6 infection (18/40 patients [45%]; P=.001). Peak CMV viral load was 24, 147+/-6799 copies/mL in patients with HHV-6 infection versus 8391+/-4598 copies/mL in patients without HHV-6 infection (P=.001). Symptomatic CMV disease was more common in patients with HHV-6 infection than it was in those without infection (15/48 patients [31. 3%] vs. 4/10 patients [10.0%]; P=.013). In a multivariate analysis including other risk factors for CMV, HHV-6 infection remained an independent risk factor for CMV disease (P=.013; odds ratio, 7.26; 95% confidence interval, 1.52-34.72). HHV-6 is associated with CMV infection and disease, thus supporting an interaction between these viruses.