Among these, CXCL10 (a chemokine) and neopterin (a metabolite of guanosine triphosphate) are abundantly present in the CSF of HAM/TSP patients, and their concentrations were shown to correlate with the degree of disease progression (Nomoto et al., 1991; Narikawa et al., 2005; Sato et al., 2013). Here, CXCL10 is linked to tropical spastic paraparesis.