Detection and isolation of human T-cell leukemia/lymphoma virus type I (HTLV-I) from cultured lymphocytes of a Brazilian TSP/HAM patient.

Some Brazilian regions are considered to be endemic for human T-cell leukemia/lymphoma virus type I (HTLV-I) infection. Several studies have shown a high prevalence of HTLV-I infection among different groups such as blood donors, hemophiliacs and patients suffering from hematological and neurological diseases. Cases of adult T-cell leukemia/lymphoma as well as tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM) have already been described in Brazil. We report the isolation of an HTLV-I strain from cultured lymphocytes of a TSP/HAM patient. An IL-2-dependent HTLV-I-infected T-cell line (ROB) expressing viral antigens was established and reverse transcriptase activity could be detected in the culture supernatant. Ultrastructural analysis showed immature and mature HTLV retrovirus particles. Finally, HTLV-I provirus type I was demonstrated by the polymerase chain reaction. This is the first isolation completely carried out in Latin America. The molecular analysis of viral strains, now in progress, should clarify the molecular epidemiology of HTLV-I in Brazil.