Sixteen antiretroviral-naive patients are randomized to either remain antiretroviral-naive (no treatment) or receive zidovudine daily (treatment). Additionally, 16 patients with 26 or more weeks of ongoing zidovudine (AZT) therapy are randomized to either continue on their prestudy AZT regimen or add didanosine (ddI) daily to their baseline AZT dose. Patients remain on their assigned treatment arms for 8 weeks. A lymph node biopsy is performed on day 0 and at week 8. Patients are evaluated at weeks 2, 4, 6, 8 and 9.