Development of a new quantitative real-time HHV-6-PCR and monitoring of HHV-6 DNAaemia after liver transplantation

Abstract

A quantitative HHV-6 PCR (qPCR) assay was developed and compared to an "in-house" qualitative PCR and to the commercial quantitative Argene CMV, HHV6, 7, 8 R-gene™ test. Clinical specimens consisting of 127 whole blood and 57 cerebrospinal fluid (CSF) specimens were tested using the two qPCRs and the qualitative PCR in parallel. When the qualitative PCR was used as a "gold standard," the sensitivities of the qPCRs for the blood samples were 86% for the "in-house" qPCR and 76% for the Argene's test and the specificities were 96% and 92%, respectively. With CSF specimens the sensitivities were 92% and 80% and the specificities 98% and 82%, respectively. Furthermore, the two qPCRs were compared in the monitoring of liver transplant patients and retrospectively correlated to HHV-6 antigenaemia. In total, 223 blood specimens were tested. HHV-6 antigenaemia had been found in 21/36 (58%) patients and HHV-6 DNAaemia was demonstrated in 18/36 (50%). Viral loads by the "in-house" test varied from 280 to 19700 copies/ml (median 1200) and by Argene's test from 120 to 24070 copies/ml (median 458). The correlation of viral loads between the two qPCRs was good (R=0.94, p<0.01). The new in-house test was found to be reliable for the detection and quantitation of HHV-6 DNA in clinical specimens.