A prospective study of human herpesvirus-6 infection in renal transplantation.

Sixty-five kidney transplant recipients and their (22 living related and 43 cadaveric) donors were studied prospectively to determine the relationship between kidney transplantation and human herpesvirus-6 (HHV-6) infection. The virus isolation from peripheral blood and other tissues and sequential determination of neutralizing antibodies to HHV-6 were performed during 3 months following the transplantation. All of the donors and their recipients examined had neutralizing antibodies to HHV-6 at the time of renal transplantation and the virus was not isolated from them. HHV-6 was isolated from 3 renal tissues (2 living related and 1 cadaveric) obtained during transplant surgery, but not from their blood at that time. HHV-6 viremia occurred in 9 (14%) of the 65 recipients around 2 to 4 weeks after the transplantation. An additional 27 recipients showed a significant rise in the antibody titer. Thus, the infection with HHV-6 was confirmed in 36 (55%) of the 65. These results indicate that the virus is activated in many cases in the early posttransplant period and that HHV-6 establishes in vivo latency in the kidney tissue. There was no correlation between HHV-6 infection and acute rejection or the antirejection prophylaxis.