Chromosomally integrated human herpesvirus-6 in kidney transplant recipients

Background. During primary infection, human herpes-virus-6 (HHV-6) may become integrated into the chromosome. This entity, termed chromosomally integrated HHV-6 (CIHHV-6), is often mistaken as active infection and treated unnecessarily. The prevalence of CIHHV-6 in kidney transplant recipients is not known. Methods. We performed quantitative HHV-6 polymerase chain reaction assay on whole blood samples collected from 47 kidney recipients. CIHHV-6 was defined as HHV-6 DNA levels >1 x 10(6) genomes/mL. Results. One of 47 kidney recipients was found to have CIHHV-6. The prevalence of CIHHV-6 was calculated at 2.1% (95% confidence interval, <0.01-12.1%). Despite an increase in HHV-6 DNA level after transplant, the patient did not develop clinical HHV-6 disease. Conclusions. CIHHV-6 may be observed in kidney transplant recipients. Clinicians should be aware of this entity so as not to provide unnecessary treatment to asymptomatic patients with CIHHV-6.