SEROEPIDEMIOLOGY, VIRAL ISOLATION, AND MOLECULAR CHARACTERIZATION OF HUMAN T-CELL LEUKEMIA LYMPHOMA VIRUS TYPE-I FROM LA-REUNION-ISLAND, INDIAN-OCEAN/

Data indicate the presence in the Seychelles Islands of a high level o f human T cell leukemia/lymphoma virus type I (HTLV-I) endemicity as w ell as the presence of tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM). We present here the results of an hospital surve y performed since 1988 in La Reunion Island, located in the Indian Oce an southeast of the Seychelles archipelago, aimed at evaluating HTLV-I endemicity, detecting HTLV-I-associated diseases, and characterizing viral isolates. Seven individuals were found to have HTLV-I-specific a ntibodies in their sera. These include 3 of 257 patients from St. Pier re Hospital, 1 of them exhibiting a typical clinical feature of TSP/HA M (the first described case in this region), 1 blood donor of 3900, an d 3 relatives. A further nine individuals exhibiting only ''gag-encode d proteins'' by Western blot (p19 and/or p24 bands) were found negativ e by polymerase chain reaction using LTR, pol, and tar HTLV-I specific primers. A long-term T cell line, designated Mel.J, exhibiting T cell activation markers (CD4(+), CD25(+), HLA-DR(+)), and producing HTLV-I antigens and viral particles, was established from one of the HTLV-I, -seropositive patients. The sequence of a 522-bp fragment correspondin g to the carboxy terminus of gp46 and the majority of gp21 were determ ined for five HTLV-I-seropositive individuals, including the TSP/HAM p atient. Alignment and phylogenetic comparison of these five nucleotide sequences with all the 53 other available HTLV-I env sequences demons trated that the virus from La Reunion Island belongs to the group of t he HTLV-I cosmopolitan subtype and is not related to the Melanesian HT LV-I variants.