IL6 and tropical spastic paraparesis: HAM/TSP patients show high frequencies of Tax-specific CD8+ T cells in peripheral blood and cerebrospinal fluid, high antibody titers to HTLV and increased production of proinflammatory cytokines (IFN-γ, TNF-α, interleukin-1beta (IL-1 β), IL-6 and IL-12) [17,37].