Indeed, it is highly significant that the work of Abrahäo et al. has shown that concomitant HTLV-1/HIV infection augments production of the Th-1 cytokines interleukin-2 (IL-2) and IFN above that of single HTLV-1 or HIV infected individuals which is entirely consistent with this hypothesis [39]. The gene discussed is IFNA1; the disease is HIV infectious disease.