In HAM/TSP patients, a previous report on the TCR analysis showed a direct demonstration of clonal expansions within both CD4+ and CD8+ cells in HTLV-1 infections (Eiraku et al. 1998) and shared amino acid motif in the CDR3β in Tax-specific CTL in HLA-A*0201 HAM/TSP patients (Bourcier et al. 2001; Saito et al. 2001). This evidence concerns the gene HLA-A and tropical spastic paraparesis.