Potent antiretroviral therapies that suppress HIV replication have permitted mathematical modeling of the dynamics of HIV infection and clearance by measurement of the decay of viral load in plasma. When de nova infection is blocked by antiretroviral therapy, the viral load decreases exponentially after a short initial lag time ("shoulder"). This rapid decline is followed by a slower second-phase decay. The intent of this study is to utilize four antiretroviral agents (zidovudine, lamivudine, nevirapine, indinavir) and very frequent measures of viral load to explore the drug-specific kinetics of the "shoulder". The decay of long-lived HIV-infected tissue macrophages is thought to be the major determinant of the slow second phase. Further, the study intends to use immune modulating agents with the potential to increase the turnover of infected macrophages, GM-CSF or IL-12, to accelerate the second phase of viral decay.

Patients are assigned to Group A (16 patients) or to Group B (8 patients). Patients in Group A are randomized to 1 of the following 4 initial treatment arms:

ARM A: Final dose combination (FDC) Zidovudine (ZDV)/Lamivudine (3TC). ARM B: Nevirapine (NVP). ARM C: Indinavir (IDV). ARM D: FDC ZDV/3TC plus NVP plus IDV. The initial regimen is maintained over the first 72 hours and blood for viral dynamic evaluations collected while patients are maintained as inpatients. Then, patients in Arms A, B, and C initiate FDC ZDV/3TC plus NVP plus IDV.

Patients assigned to Group B begin the following 4-drug regimen on Day 0:

ARM E: FDC ZDV/3TC plus NVP plus IDV.

On Day 7, patients in both Groups A and B are randomized to receive one of the following therapies in addition to their 4-drug regimen:

ARM F: GM-CSF daily for 2 weeks, then thrice weekly (MWF). ARM G: IL-12 twice weekly. ARM H: No immune modulation. Patients may be hospitalized to initiate immune modulation or may be treated as outpatients. Immune modulation is discontinued after Week 14. Patients maintain their 4-drug regimen through Week 48. [AS PER AMENDMENT 6/11/99: The study duration has been extended to 96 weeks.] Hepatitis A vaccine (inactivated) is administered on Weeks 16 and 40 [AS PER AMENDMENT 2/13/98: to patients whose baseline hepatitis A serology was negative].