Conflicting data regarding IL-17 production in HTLV-1 infected subjects and a possible role along with IFN-γ in the proinflammatory milieu observed in HAM/TSP patients led us to investigate the production of inflammatory cytokines of CD4+ T cells from 9 uninfected, 8 HTLV-1 asymptomatic carriers and 10 HAM/TSP patients. Here, CD4 is linked to tropical spastic paraparesis.