Endonuclease analyses of DNA of human herpesvirus-6 isolated from blood before and after bone marrow transplantation.

Three strains of human herpesvirus-6 (HHV-6) were isolated from peripheral blood mononuclear cells of a leukemic child with the antibody of HHV-6 before and after bone marrow transplantation (BMT); two strains were obtained before BMT and one after BMT. The DNA extracted from the three isolates was analyzed by six different restriction endonucleases. The cleavage profiles of two strains obtained before BMT were different, but the third strain isolated after BMT was identical with one of the two, which suggest reactivation of HHV-6 from the recipient's own body after BMT and possible mutation or super-infection of the virus in an immunocompromised patient.