Most of individuals after infection remain as asymptomatic carriers (~ 90 to 95%) and are potential disseminators, while less than 10% develop diseases with unfavorable outcomes, among them HTLV-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), a chronic inflammatory neurodegenerative disease with important morbidity for the patients [2, 3], and about 1–5% of them undergo clonal expansion of infected CD4+ T-cells and develop ATL after a long latency period. This evidence concerns the gene CD4 and tropical spastic paraparesis.