Human Herpesvirus 6 as an Indicator of Cytomegalovirus Infection and Its Attributable Disease Symptoms in Liver Transplant Recipients.

OBJECTIVES: Human β-herpes viruses, including cytomegalovirus and human herpesvirus 6, can become activated in liver transplant patients. Here, we evaluated the effects of human herpesvirus 6 infection as an independent factor on cytomegalovirus infection and the occurrence of associated diseases in liver transplant patients.

MATERIALS AND METHODS: In this cross-sectional study, 46 patients who underwent deceased-donor liver transplant at Nemazi Hospital, Shiraz University of Medical Sciences (Shiraz, Iran) were prospectively monitored for cytomegalovirus and human herpesvirus 6 infections during 3 months posttransplant. Taq-man real-time polymerase chain reaction assay as an accurate and rapid test and pp65-anigenemia as the standard test were used to monitor cytomegalovirus infections, whereas human herpesvirus 6 infection was monitored by Taq-man real-time polymerase chain reaction assay. We also followed clinical findings from laboratory data and symptoms of cytomegalovirus infections.

RESULTS: Active cytomegalovirus infection was detected in 23 liver transplant recipients (50%), of which 17 (74%) were diagnosed with cytomegalovirus-related diseases. Active human herpesvirus 6 infection was detected in 25 patients (54%). Thirteen of 17 cytomegalovirussymptomatic patients had coinfection with human herpesvirus 6. In 10 ofthe 13 patients with coinfection, human herpesvirus 6 DNAemia appeared significantly earlier by 9 days than cytomegalovirus infection. In the pp65 antigenemia test, the mean number of cytomegalovirus-infected polymorphonuclear cells was 42.47 ± 5.41, which was correlated with incidence of clinical presentation. In symptomatic patients, average serum and polymorphonuclear cell viral loads of cytomegalovirus were 12064.59 copies/mL and 6735 copies/2 × 105 cells,respectively, with significant differences between the loads and cytomegalovirusattributable disease symptoms. Average human herpesvirus 6 DNA burden in serum samples of symptomatic patients was 11283 copies /mL, which was statistically related to cytomegalovirus-attributable disease symptoms.

CONCLUSIONS: We found that human herpesvirus 6 infection is often associated with cytomegalovirus reactivation and cytomegalovirus-attributable disease symptoms.