INFECTION OF ORAL MUCOSAL CELLS BY HIV-1

HIV-1 transmission through saliva represents minimal risk, if any at a il. However, recent studies using the in situ polymerase chain reactio n (PCR) have shown that desquamated oral epithelial cells in saliva ha ve integrated HIV-1 provirus DNA in their nuclei. Additionally, a high prevalence of HIV-1 RNA (13/27, 48%) is detected in saliva, correlate d with lowered CD4 counts (64% with CD4 < 200 per mm(3) and 38% with C D4 > 200 per mm(3)). Results of in situ PCR and transmission electron microscopy on mucosal epithelial cells, obtained clinically by scrapin g, indicate that these cells contain HIV-1 provirus DNA and epithelial cell-associated viral particles consistent with HIV-1, raising the po ssibility of productive infection. Buccal oral biopsies on HIV-1 serop ositive subjects were obtained and, using in situ PCR, HIV-1 provirus DNA was detected; the signal was present in discrete foci in the epith elial layer ranging from the basal border to more superficial cells. A lso, HIV-1 was localized in cells of lymphocytic and Langerhans lineag e. The mechanism of infection and production of HIV-1 by oral mucosal cells needs to be studied further.