The chemokines CCL3, CCL4, and CXCL10 and CXCL11 ligands of CCR1, CCR5, and CXCR3 were found in the cerebrospinal fluid of HTLV-1-asymptomatic carriers and HAM/TSP patients, suggesting that monocytes can migrate to the central nervous system and be involved in HAM/TSP development [232,233]. The gene discussed is CCL4; the disease is tropical spastic paraparesis.