These data collectively suggest that CD8+ and CD2+ EVPs may be significant in two respects: 1) CSF EVPs possessing CD8 and/or CD2 may be used as a potential biomarker for viral-mediated neurological diseases such as HAM, and 2) CD8+ and/or CD2+ EVPs may themselves mediate areas of the disease process in infected individuals. This evidence concerns the gene CD2 and tropical spastic paraparesis.