To evaluate the anti-HIV effect of single agent versus combination therapy with zidovudine (AZT) and interferon alfa-2a (IFN-A2a), as measured by p24 protein expression, viral growth and infectivity in patients with symptomatic HIV disease. To assess the safety of low dose schedules of AZT and IFN-A2a, alone and in combination, as measured by neutrophil counts and hepatic transaminase levels. To evaluate the comparative effects of single agent versus combination therapy with AZT and IFN-A2a on CD4 cell counts and skin test reactivity.