From 1982 to 1985, 89 HIV-1 seropositive men with persistent generalized lymphadenopathy (PGL) were enrolled into a prospective longitudinal study. In February 1988, after a mean observation time of 45 months, 23 patients had progressed to AIDS with opportunistic infection (AIDS/OI), 4 had developed Kaposi's sarcoma, 47 had developed HIV-related symptoms, 14 still had PGL as only symptom, and 1 was lost to follow-up. Patients with CD4 lymphocytes less than or equal to 0.40 x 10(9)/l as well as patients with HIV antigenaemia and those lacking antibodies to p24 all had a significantly higher risk of developing AIDS/OI within 30 months of observation than other patients. HIV antigen was present in 70% and antibodies to p24 were lacking in 61% of the patients at the time of AIDS/OI diagnosis. All but one (96%) of the AIDS/OI patients had CD4 numbers less than or equal to 0.20 x 10(9)/l at the same time. The estimated median time to AIDS/OI in patients with HIV antigenaemia was 21 months and in patients lacking p24 antibodies 27 months. In patients with CD4 numbers less than or equal to 0.20 and 0.40 x 10(9) cells/l the estimated median time to AIDS/OI was 14 months and longer than 30 months, respectively.