IFNG and tropical spastic paraparesis: The presence of HTLV-1 in CNS induces inflammation and cytokine release by the resident CNS cells and migratory immune cells characterized by increased levels of TNF, IFN-γ, IL-1α, IL-β, and IL-6 in CSF and spinal cords of HAM/TSP patients (Umehara et al., 1994; Banerjee et al., 2007b; Champs et al., 2019).