Use of real-time PCR to monitor human herpesvirus 6 reactivation after allogeneic bone marrow transplantation

Reactivation of human herpesvirus 6 (HHV-6) is common following allogeneic marrow transplantation, however, little is known about the immune control a nd pathogenic potential of HHV-6 infection after transplantation. In order to determine whether reactivation of HHV-6 plays an important role in the d evelopment of complications in patients undergoing allogeneic bone marrow t ransplantation or not, we developed a very rapid quantification of viral DN A using a LightCycler. The amount of viral DNA was determined using a super natant of a chronically infected cell line [TaY(OK)] which contains a known amount of viral DNA. Peripheral blood cells were collected from 5 patients undergoing allogeneic bone marrow transplantation once before transplant a nd once per week after transplant for 8-24 weeks. The real-time PCR system revealed that there was a linear correlation in the range of 10(1) to 10(5) molecules of reference. Using this system, we have found the presence of n on-diagnosed HHV-6 reactivation as well as symptomatic infection, indicatin g the potential for routine implementation of this technology for laborator y diagnosis of HHV-6 infection. Our study shows that this method of rapid q uantification of HHV-6 genomes by the real-time PCR using a LightCycler may be useful not only to understand the reconstitution of the immune system f ollowing marrow transplantation but also to manage the care of patients.