The purpose of this study is to evaluate the safety and tolerability of giving IL-2 plus anti-HIV (antiretroviral) therapy to HIV-positive patients with CD4 cell counts (cells of the immune system that fight infection) of at least 350 cells/mm3. This study will also examine the ability of antiretroviral therapy combined with IL-2 to boost the immune system.

IL-2, given through injection under the skin, in combination with anti-HIV therapy can increase CD4 cell counts. This study examines 3 doses of IL-2 in order to determine the safest and most effective dose to use.

Interleukin-2 administered subcutaneously, in combination with antiretrovirals, results in an increased CD4+ cell count that might impact upon HIV disease progression. A Phase III trial involving large numbers of HIV-positive patients is the next step in the development process. To develop appropriate clinical experience with this combination, this Phase II trial will allow administration of IL-2 plus antiretroviral therapy to a small number of patients in sites being considered for the Phase III trial.

Patients receive antiretrovirals alone or antiretrovirals plus IL-2 given subcutaneously. Three doses of IL-2 are studied, with 12 patients evaluated at each dose. When at least 9 of the first 12 patients complete the 5-day dosing period without dose-limiting toxicity, the next 12 patients are treated at the next highest dose every 12 hours for 5 days every 8 weeks; when this dose is tolerated, the last 12 patients randomized receive the highest study dose every 12 hours for 5 days every 8 weeks. Patients enrolled at the first two doses of IL-2 who complete three courses of treatment have their dose escalated to a maximum of the highest study dose.

Inclusion Criteria

Patients may be eligible for this study if they:

• Are HIV-positive.
• Have a CD4 cell count greater than or equal to 300 cells/mm3.
• Have no AIDS-defining illnesses.
• Are at least 18 years old.
• Have been on antiretroviral therapy for at least 7 days prior to study entry.

Exclusion Criteria

Patients will not be eligible for this study if they:

• Abuse alcohol or drugs, or have any serious psychiatric or medical illnesses that would affect their safety or ability to complete the study.
• Have a history of cancer (other than Kaposi's sarcoma), an AIDS-defining illness, a central nervous system abnormality, or an autoimmune/inflammatory disease.
• Are pregnant or breast-feeding.
• Have ever received IL-2.