Reactivation of human herpesvirus type 6 in multiple organ failure syndrome.

Human herpesvirus type 6 (HHV-6) and cytomegalovirus (CMV) are known to interact with the production of cytokines. In this study, we sought to determine the incidence of HHV-6 and CMV reactivation during multiple organ failure syndrome (MOFS) and to evaluate the potential effects of viral replication on both the morbidity and mortality associated with MOFS. Viral reactivation was assessed by use of specific polymerase chain reaction (PCR) analysis of the serum samples obtained from 48 consecutive patients with MOFS (the MOFS group) and from 48 sex- and age-matched patients with <2 organ failures (the control group). In addition, HHV-6 replication was assessed in 106 blood donors (the normal group). The incidence of HHV-6 replication was higher in the MOFS group than in the control and normal groups (26 [54%] of 48 vs. 7 [15%] of 48 and 5 [5%] of 106, respectively; P<.0001), with apparently no influence on morbidity and mortality rates. In contrast, reactivation of CMV was found in a single patient. Further studies are needed to evaluate the pathogenesis of HHV-6 replication in critically ill patients.