PBMCs from HAM-TSP patients further show an increased proportion of IL-17-expressing CD4 T-cells (86) and of inflammatory CD4+CD8+ T-cell populations whose IFN-γ, TNF-α, IL-17, and CXCL10 productions are one of the most pronounced among stimulated T-cells (87). The gene discussed is CD4; the disease is tropical spastic paraparesis.