A Phase II Study of Low-Dose Interleukin-2 by Subcutaneous Injection in Combination With Antiretroviral Therapy Versus Antiretroviral Therapy Alone in Patients With HIV-1 Infection and at Least 3 Months Stable Antiretroviral Therapy

PRIMARY: To examine the effect of aldesleukin ( IL-2 ) on viral activity in the blood. To determine the safety of low-dose IL-2 in combination with antiretroviral therapy versus antiretroviral therapy alone. SECONDARY: To examine delayed type hypersensitivity responses to skin test antigens and antibody responses to protein and polysaccharide vaccines. The profound immune impairment that results from HIV-1 infection is due, at least in part, to the loss of CD4+ T cells and the cytokines these cells secrete, especially IL-2 and interferon-gamma. Antiretroviral agents do not directly address the problem of immune impairment. Replacement of IL-2 at nontoxic doses may prevent or delay clinical immunosuppression and its attendant opportunistic infections. Also, since patients with HIV-1 infection respond suboptimally to routine protein and polysaccharide immunizations, IL-2 may provide an adjuvant effect on vaccine responses. The profound immune impairment that results from HIV-1 infection is due, at least in part, to the loss of CD4+ T cells and the cytokines these cells secrete, especially IL-2 and interferon-gamma. Antiretroviral agents do not directly address the problem of immune impairment. Replacement of IL-2 at nontoxic doses may prevent or delay clinical immunosuppression and its attendant opportunistic infections. Also, since patients with HIV-1 infection respond suboptimally to routine protein and polysaccharide immunizations, IL-2 may provide an adjuvant effect on vaccine responses. Patients are randomized initially to receive their own antiretroviral therapy alone or in combination with IL-2 for 24 weeks, after which each group is crossed over to the other treatment assignment (i.e., IL-2 is either added or deleted from the regimen) for an additional 24 weeks. Patients who are vaccine eligible receive influenza, tetanus and diphtheria toxoid, and meningococcal polysaccharide vaccines at week 4, and those who have not received pneumococcal vaccine prior to study entry will receive it at week 8.