DETECTION OF HTLV-I IN PERIPHERAL-BLOOD LYMPHOCYTES FROM PATIENTS WITH CHRONIC HTLV-I-ASSOCIATED MYELOPATHY TROPICAL SPASTIC PARAPARESIS AND ASYMPTOMATIC CARRIERS BY PCR IN-SITU HYBRIDIZATION

Less than 5% of people infected with human T-lymphotropic virus type I (HTLV-I) develop HTLV-I-associated myelopathy/tropical spastic parapa resis (HAM/TSP), a chronic progressive neurologic disease. A number of factors have been implicated in the development of HAM/TSP including heterogeneity of viral sequences, host-genetic background, viral-speci fic cellular immune responses and viral load. This study examined the presence of HTLV-I tax DNA in peripheral blood lymphocytes (PBL) from 2 chronic HAM/TSP patients and 2 asymptomatic HTLV-I carriers by using PCR-in situ hybridization (PCR-ISH) for the in situ presence of provi ral HTLV-I tax DNA. By this technique, rare PBL from these HTLV-I-infe cted individuals contained HTLV-I DNA. PCR-ISH did not detect any diff erence in the number of infected cells between HAM/TSP patients and as ymptomatic carriers.