TNF and tropical spastic paraparesis: Furthermore, increased concentrations of inflammatory markers, such as neopterin [10], tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IFN-γ [11], and an increase in HTLV-1 antigen-specific intrathecal antibody synthesis [12] have been observed in the cerebrospinal fluid (CSF) of patients with HAM/TSP.