Detection of HIV in oral mucosal cells

OBJECTIVE: To determine the prevalence of HIV DNA and RNA and the morphologic localization of HIV in the oral cavity of HIV‐seropositive subjects. DESIGN: A cross‐sectional analysis of saliva, buccal scrapings and buccal biopsies from HIV‐seropositive injecting drug users (IDUs). SUBJECTS AND METHODS: Whole saliva, buccal mucosal scrapings and buccal biopsies were obtained from HIV‐seropositive and seronegative IDUs. Presence of HIV DNA and RNA was assessed by polymerase chain reaction (PCR) and reverse transcriptase PCR (RT‐PCR). RT in situ PCR was used to detect HIV tat/rev RNA in buccal mucosal scrapings. Host‐cell integrated HIV‐proviral DNA in buccal biopsies was detected by in situ PCR. Presence of intact HIV viral particles in buccal scrapings was assessed by electron microscopy. RESULTS: HIV DNA was detected in 40% (18/45) and HIV RNA in 69.2% (25/36) of saliva samples from HIV‐seropositive IDUs. Viral particles consistent with HIV were localized in inter‐epithelial spaces by electron microscopy. RT in situ PCR revealed the presence of HIV tat/rev RNA in 36% (8/22) of the seropositive samples tested. CONCLUSIONS: Our results suggest that epithelial cells can be productively infected by HIV. Epithelial cells in buccal mucosa may acquire HIV in the basal layers through contact with submucosal HIV‐positive lymphocytes and/or Langerhans' cells. HIV infection may also spread by inter‐epithelial cell contact. As HIV infected cells mature they travel to more superficial layers and are shed into the oral cavity.