The fact that HTLV-1-specific CD8+ cytotoxic T lymphocyte (CTL) clones derived from patients with HAM/TSP are actively producing CCL3 and CCL4 chemokines (Cocchi et al., 1995), reinforces the hypothesis that HTLV-1 can influence HIV-1 replication via chemokine expression and release. This evidence concerns the gene CCL4 and tropical spastic paraparesis.