We also found a significant smaller Th17/CD39+CD25− T-cell ratio in HAM/TSP patients as compared to HTLV-1-infected asymptomatic carriers, considering the number of IL-17 secreting cells and the frequency or number of CD39+CD25−CD4+ T cells (Fig. S 5A). This evidence concerns the gene ENTPD1 and tropical spastic paraparesis.