Pre-clinical studies in macaques chronically infected with SIV [25]–[28], as well as clinical studies in patients with HIV-1 infection or receiving treatment with immunosuppressive antineoplastic drugs [29]–[32], have documented beneficial effects of short-term courses of IL-7 therapy, resulting in the proliferation and numerical expansion of naïve and CM CD4+ and CD8+ T cells in peripheral blood and secondary lymphoid organs. The gene discussed is CD4; the disease is HIV-1 infection.