DETECTION OF HUMAN T-LYMPHOTROPIC VIRUS TYPE-I (HTLV-I) TAX RNA IN THE CENTRAL-NERVOUS-SYSTEM OF HTLV-I-ASSOCIATED MYELOPATHY TROPICAL SPASTIC PARAPARESIS PATIENTS BY IN-SITU HYBRIDIZATION

Autopsy specimens from 3 patients with human T-Lymphotropic,virus (HTL V-I)-associated myelopathy/tropical Spastic paraparesis (HAM/TSP) were examined for the presence of HTLV-I:in the central nervous system (CN S). In situ hybridization using an HTLV-I tax RNA probe detected cells containing HTLV-I RNA in Spinal cord and cerebellar sections. HTLV-I infected cells were located within the white matter and, in particular , within the anterior and lateral funiculi of the spinal cord. Consist ent with previously described HAM/TSP pathology, there were perivascul ar infiltrates in these CNS specimens. Significantly, HTLV-I RNA was n ot localized to these infiltrates but was detected deeper with;in the neural tissue. Furthermore, phenotypic analysis demonstrated that at l east some of the infected cells were astrocytes. While previous polyme rase chain reaction studies have demonstrated the presence of proviral HTLV-I in CT;TS specimens, here we provide evidence for the in situ e xpression of HTLV-I RNA in the CNS of HAM/TSP patients.