CX3CL1 and tropical spastic paraparesis: In HTLV-1 infected subjects, classical monocytes express high levels of CCR5, CXCR3 and CX3CR1 and a correlation has been observed between the proviral load and the migratory capacity of classical monocytes toward CCL2, CCL5, and CX3CL1, suggesting that migration of monocyte into inflammatory sites is related with persistence of HTLV-1 infection and progression of HTLV-1 associated inflammatory diseases, such as Myositis, Uveitis, and HAM/TSP (de Castro-Amarante et al., 2016).