Persistent paradox of natural history of human T lymphotropic virus type I: parallel analyses of Japanese and Jamaican carriers.

Human T lymphotropic virus type I (HTLV-I) is endemic in southern Japan and the Caribbean, but the incidence of HTLV-I-associated diseases varies across geographic areas. We compared markers of disease pathogenesis among 51 age- and sex-matched HTLV-I carrier pairs from Japan and Jamaica. The mean antibody titer (P=.03) and detection of anti-Tax antibody (P=.002) were higher in Jamaican subjects than in Japanese subjects, but provirus load was similar between the 2 groups (P=.26). The correlation between antibody titer and provirus load was more prominent among Jamaican subjects than among Japanese subjects (P=.06). These findings underscore the differences in host immune response to HTLV-I infection in 2 populations.