CXCL10 produced by astrocytes in the spinal cord of HAM/TSP patients recruits CXCR3-positive cells (including HTLV-1-infected cells and inflammatory cells) into the spinal cord; in addition, interferon γ produced by the recruited cells further induces CXCL10 production from astrocytes in the spinal cord lesions (Ando et al., 2013). Here, CXCL10 is linked to tropical spastic paraparesis.