Detection of HTLV Type I Provirus by in Situ Polymerase Chain Reaction in Mouthwash Mononuclear Cells of HAM/TSP Patients and HTLV Type I Carriers

Molecular studies have revealed the presence of HTLV-I provirus DNA in saliva of HTLV-I-infected subjects. However, cellular localization has not been determined. In the present study, we have used in situ PCR technique to study saliva-associated cells for localization of HTLV-I proviral DNA. We found that HTLV-I proviral DNA was present in the nuclei and cytoplasm of salivary lymphocytes in five (71%) of seven HTLV-I-sero-positive subjects. The percentage of infected cells in positive mouthwash samples ranged from 0.5 to 2%. None of the HTLV-I-negative patients had HTLV-I provirus in saliva. The localization of HTLV-I provirus DNA suggests that salivary lymphocytes can serve as vector for HTLV-I infection through saliva.