Virologic analysis. In patients 1-7 seroconversion occurred 11-27 days after the onset ofsymptoms. In patient 8, despite early treatment with zidovudine, seroconversion occurred 41 days after exposure to HIV-I-infected blood. Transient HIV-l antigenemia before seroconversion was detected in seven of eight patients. In patients 1-5 only NSI isolates were recovered. In patients 6 and 8 only SI isolates were detected. An SI isolate was obtained from patient 7 at seroconversion; at day 42 an NSI isolate was recovered and subsequently SI isolates reappeared, preceding progression to AIDS. In II seroconverting participants of the Amsterdam cohort from whom virus was obtained at seroconversion and on at least two dates after seroconversion, only NSI isolates were recovered (data not shown). For three of the individuals studied, the virus donor was identified. In two cases the viruses of donorrecipient pairs displayed similar phenotypes: The wife ofpatient 2 yielded an NSI isolate, and an SI isolate was recovered from the patient whose blood infected patient 8. A discordance of viral phenotype was observed in the third donor-recipient pair: An SI isolate was recovered from the steady homosexual partner of one of the cohort participants (subject 17) before and after the estimated time of transmission. For subject 17, however, isolates obtained at and after seroconversion were of the NSI phenotype.
Immunologic analysis. At or directly preceding seroconversion, a transient CD4+ and CD8+ T lymphocytopenia was observed in six of the eight frequently sampled individuals, profound in patients 1,3,7, and 8 «0.3 X 109/1) and less dramatic in patients 4 and 6. After seroconversion, CD8+ T cell numbers recovered completely but CD4+ T cell numbers recovered only partly. In the 16 subjects with NSI isolates, except for patient 5, CD4+ T cell numbers remained stable and in the normal range until the end ofthe study. No opportunistic infections were observed in this group; however, two individuals developed Kaposi’s sarcoma with normal CD4+ T cell numbers (1.3 X 109/1 and 0.7 X 109/1, respectively) 25 and II months after seroconversion. In contrast, in all three individuals with SI isolates, CD4+ T cell numbers, after a temporary recovery to low-normal values, declined rapidly in individual 6 and precipitously in individuals 7 and 8. Patient 7 developed Pneumocystis carinii pneumonia 6 months after seroconversion. In patient 8, extrapulmonary Mycobacterium tuberculosis was diagnosed 19 months after seroconversion. After seroconversion, in five of the eight closely followed individuals, a period of CD8+ lymphocytosis was observed. Elevation of CD8+ T cell numbers was most pronounced and most prolonged (~3 months) in individuals 1,2, and 4, who had the most severe symptoms ofacute HIV-l infection. CD8+ T cell counts remained low in individual 3, in whom dysphagia was the only symptom of acute HIV-I infection and in patient 8 who had no early symptoms.