Phase II/III Study Evaluating the Effect of IL-2 on Preservation of the CD4 T-Lymphocytes After Interruption of Antiretroviral Treatment in HIV-Infected Patients With CD4 T-Lymphocyte Count Greater Than 500 Cells/mm3 Who Received Antiretroviral Tx

This study will examine whether interleukin-2 (IL-2) given before the interruption of antiretroviral (ARV) treatment could significantly extend the period of time that a patient is temporarily not taking ARV treatment and also preserve CD4 counts above 350 cells per microliter. There will be an evaluation of the toxicity, or extremely harmful effects, of ARV, and the effect on quality of life. The use of ARV medications has greatly improved the condition and mortality of HIV-infected patients. But when used long term, those medications have been associated with great toxicities and medication fatigue. As a result, patients may not adhere to ARV use, and resistance to viruses may grow. The CD4 molecule is on the surface of helper T-lymphocytes, or T-helper cells. It serves as the primary receptor for HIV-1 and HIV-2, allowing the virus to gain entry into its host. The CD4 count increases immediately in response to ARV, giving an estimate of the state of a patient's immune system. Thus, it is a strong marker of the immediate risk of an opportunistic infection, one that takes advantage of a person's weakened immune system. IL-2 is a molecule naturally produced by activated T cells. In patients with HIV, IL-2 treatment can increase CD4 counts but the clinical importance of this increase is not clear. This study will compare the decline in CD4 count, when ARV is interrupted, in two random groups of participants: (1) those who will receive three cycles of IL-2 (one every 8 weeks) in combination with ARV therapy for the first 24 weeks of the study before stopping ARV and (2) those who will receive ARV therapy without IL-2 for 24 weeks before stopping ARV. Patients 18 years of age or older who have HIV-1 infection and who have been on ARV therapy for at least 1 year, and who currently have a CD4 count 500 cells per microliter or higher and never had a CD4 count of less than 200 cells per microliter and a viral load less than the limit of detection, may be eligible for thi