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 o r through a general immunomodulatory effect. To examine this possibility, 8 8 liver transplant recipients were monitored with serial HHV-6 polymerase c hain reaction (PCR), CMV antigenemia, and CMV plasma viral load. HHV-6 infe ction 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 recurre nce was significantly more common in patients with HHV-6 infection (38/48 p atients [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 infecti on remained an independent risk factor for CMV disease (P = .013; odds rati o, 7.26; 95% confidence interval, 1.52-34.72). HHV-6 is associated with CMV infection and disease, thus supporting an interaction between these viruse s.