RESUMEN
BACKGROUND: Human herpesvirus-6 (HHV-6) frequently reactivates in immunocompromized individuals. Most commonly HHV-6 DNA is detected without organ localized disease. This HHV-6 DNAemia usually occurs in patients who also have CMV reactivations. The question if reactivation of one virus causes reactivation of the other, or whether both viruses reactivate independently, cannot be answered in populations with high seroprevalence for both viruses. Our study is the first in which 35 patients have been included who were CMV seronegative prior to transplantation. OBJECTIVE: We investigated the occurrence of HHV-6 reactivations in relation to the CMV-serostatus of renal transplantation donor and recipient. STUDY DESIGN: 9 consecutive patients receiving a renal transplantation were included. All available stored whole blood samples were tested for HHV-6 DNA by quantitative PCR. Details including CMV serostatus of donor and recipient were recorded. RESULTS: CMV-seropositive recipients have a 68% chance of developing HHV-6 DNAemia if the kidney came from a CMV-seropositive donor, compared to 26% if the kidney came from a CMV-seronegative donor. CMV-seronegative recipients, who are bound to undergo primary CMV infections following transplantation with a renal graft from a CMV-seropositive donor, have 88% chance of developing HHV-6 DNAemia. If they receive a graft from a CMV-seronegative donor the chance of developing HHV-6 DNAemia is 22%. CONCLUSION: Receiving a renal transplant from a CMV-seropositive donor increases the chance of developing HHV-6 DNAemia. HHV-6 DNAemia is a sign of impending primary CMV infections following sero-discordant renal transplantations.