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

Abstract

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. 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. 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. 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.