CCL4 and tropical spastic paraparesis: The biology of PrPC was modulated by inflammatory cytokines and chemokines, such as IL-6, TNF-α, IL-8, and CCL4/MIP-1β, among others (Stoeck et al., 2014), which are also observed in patients with HAM/TSP (Champs et al., 2019; Souza et al., 2021; Freitas et al., 2022).