Of note, our results provide mechanistic evidence for the previously described immunovirological and clinical impact observed in vivo with IFN-β therapy in HAM/TSP patients, in an open-label trial (Oh et al., 2005), as well as two case reports with remarkable clinical response (Costa et al., 2012; Viana et al., 2014). Here, IFNB1 is linked to tropical spastic paraparesis.