Trial Information

Natural History of HTVL-I: A Cross-Sectional Study of a Cohort of Blood Donors in Jamaica

Southern Japan and the Caribbean are both endemic for human T-lymphotropic virus type I
(HTLV-I) infection. In these areas, however, epidemiology of HTLV-I appears to differ.
Various observations from population-based studies indicate that differences in host immune
response to virus infection is likely to result in different frequencies of disease
manifestations across geographic regions. While gender, age and route of infection may
partly determine host immune response, the observed geographic differences may also reflect,
in part, host genetic background as evidenced by the distribution of human leukocyte
antigens (HLA) and presence of other environmental factors.

The reported differences underscore the need for comparative studies in these endemic areas.
In addition, analyses of larger, pooled data of HTLV-I carriers from different geographic
areas are needed to ensure statistical power in studies of gene-environment interactions
with extended use of molecular markers. However, existing population-based studies from
Japan and the Caribbean are unfortunately no comparable with respect to the study subject's
age and gender distributions. In order to address this issue, we proposed a study of blood
donors in Jamaica, which enrolls a large number of both HTLV-I positive and HTLV-I negative,
consisting of subjects that are more comparable to existing Japanese study with respect to
age and sex. The proposed study will provide a basis for a comparative study of HTLV-I
carriers in Japan and Jamaica and a comprehensive analysis of host genetic background of
HTLV-I associated illnesses in the Black population.