Association of Human Herpesvirus 6 Reactivation with Severe Cytomegalovirus-Associated Disease in Orthotopic Liver Transplant Recipients

To explore the possible interaction between human herpesvirus 6 (HHV-6) and cytomegalovirus (CMV) in patients who have undergone organ transplantation, stored serum samples from 139 orthotopic liver transplant recipients were tested for HHV-6 immunoglobulin (Ig) G and IgM antibodies. HHV-6 reactivation occurred in 87 patients (62.6%) and was associated with CMV disease (P = .01), severe CMV-associated disease (P = .01), older age (P = .005), and use of muromonab-CD3 (Orthoclone; Orthobiotech) as treatment for rejection (P = .02). Trends for an association between HHV-6 reactivation and invasive fungal disease (P = .12), bacteremia (P = .10), and graft loss (P = .12) were seen. In a multivariate analysis of risk factors for severe CMV-associated disease, HHV-6 reactivation (relative risk [RR], 3.5; 95% confidence interval [CI], 1.2-10.2; P = .02), CMV donor-positive-recipient-negative match (RR, 5.7; 95% CI, 2.5-13.2; P < .001), and elevated serum creatinine level (P < .0001) were independent predictors. HHV-6 reactivation is associated with severe CMV-associated disease in liver transplant recipients.