Concurrent with the STALWART study, two phase III trials were evaluating the clinical efficacy of intermittent IL-2 plus ART compared to ART alone in approximately 6,000 patients with HIV infection: ESPRIT (Evaluation of Subcutaneous Proleukin® in a Randomized International Trial) and SILCAAT (Subcutaneous Recombinant IL-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy). The gene discussed is CD4; the disease is HIV infectious disease.