Human herpesviruses 6 and 7 as potential pathogens after liver transplant:Prospective comparison with the effect of cytomegalovirus

Because cytomegalovirus (CMV) is an important opportunistic infection after liver transplant, we conducted a prospective study to see if the same appl ied to human herpesviruses (HHV)-6 and -7. We used polymerase chain reactio n (PCR) methods optimised to detect active, not latent, infection and studi ed patients not receiving antiviral prophylaxis for CMV. Post-transplant, 5 36 blood samples were tested by PCR (median 7; range 4-50). Active infectio n with CMV was detected in 28/60 (47%), HHV-6 in 19/60 (32%), and HHV-7 in 29/60 (48%) of patients. The PCR-positive samples were tested by quantitati ve-competitive PCR to measure the virus load of each betaher-pesvirus. The median peak virus load for CMV was significantly greater than that for HHV- 6 or HHV-7. Detailed clinicopathological analyses for the whole population showed that CMV and HHV-6 were each significantly associated with biopsy-pr oven graft rejection. Individual case histories suggested that HHV-6 and HH V-7 may be the cause of some episodes of hepatitis and pyrexia. It is concl uded that HHV-6 is a previously unrecognized contributor to the morbidity o f liver transplantation, that HHV-7 may also be important and that both vir uses should be included in the differential diagnosis of graft dysfunction. (C) 1999 Wiley-Liss, Inc.