Extensive oral shedding of human herpesvirus 8 in a renal allograft recipient.

Introduction: Studies were conducted to investigate changes in the extent of human herpesvirus 8 (HHV-8) shedding and diversity of HHV-8 strains in the mouth of a renal allograft recipient who developed cutaneous post-transplantation Kaposi's sarcoma.

Methods: Matched oral and blood samples were obtained from a Saudi Arabian renal allograft recipient from 3 days before to 38 weeks after transplantation, and from his kidney donor. Polymerase chain reaction (PCR) protocols to amplify selected HHV-8 sub-genomic regions were applied to detect and quantify HHV-8 DNA. Sequence diversity was determined by cloning the PCR products and subjecting them to denaturing gradient gel electrophoresis and to nucleotide sequencing.

Results: Before transplantation, the recipient was seropositive for anti-HHV-8 immunoglobulin G, but the donor was seronegative; HHV-8 DNA could be detected in the recipient's blood, whole-mouth saliva (WMS) and buccal exfoliates, and the salivary viral load was estimated as 2.6 million genome-copies/ml. Post-transplantation, the recipient's salivary viral load initially increased to 4.1 million genome-copies/ml, and thereafter declined precipitously, coinciding with an increase in the dosage of valaciclovir given; HHV-8 DNA was detected most often in WMS compared with parotid saliva, and buccal and palatal exfoliates. Carriage of multiple HHV-8 strains was evident in blood and oral samples; whereas before transplantation strains belonging to genotypes A1 and A5 were observed, after transplantation genotype A5 strains became dominant and A2 strains emerged.

Conclusion: Immunosuppression and antiviral prophylaxis may interact to influence the spectrum of oral HHV-8 strains and the extent of post-transplantation HHV-8 shedding into the mouth.