Objectives: To examine the relation of circulating cytokines and cytokine antagonists to the progression of human immunodeficiency virus type 1 (HIV-1) disease. Design: Cross-sectional analysis. Setting: An ambulatory acquired immunodeficiency syndrome (AIDS) research clinic in Kinshasa, Zaire. Patients: 48 women with AIDS, 51 women with HIV infection who were clinically asymptomatic, and 11 female controls who did not have HIV infection, all from Zaire. Measurements: Plasma levels of interleukin-1 beta, tumor necrosis factor-alpha (TNF-alpha), interleukin-6, interleukin-8, interferon-gamma, interleukin-1 beta receptor antagonist (interleukin-1Ra), and TNF soluble receptor p55 (TNFsRp55) were assayed by specific radioimmunoassays. Plasma levels of interferon-gamma were assayed by commercial enzyme-linked immunosorbent assay. The Wilcoxon rank-sum test was used to assess the significance of mean and median differences between groups. Results: Of the 48 patients with AIDS, circulating interleukin-1 beta was detected in 2, TNF-alpha in 4, interleukin-6 in 3, and interleukin-8 in 12. None of these factors were seen in any of the 11 controls. Median values of interleukin-lp (320 pg/ml), TNF-alpha (210 pg/mL), and interleukin-8 (750 pg/mL) were elevated in HIV-infected asymptomatic patients compared with patients with AIDS (2-, 2.6-, and 18.7-fold higher, respectively; P < 0.001). Interleukin-1Ra and TNFsRp55 levels were substantially higher than interleukin-1 beta and TNF-alpha levels in HIV-infected asymptomatic patients (73- and 14-fold, respectively) and were higher than those in patients with AIDS (17.8- and 1.74-fold, respectively). Conclusion: High circulating levels of the proinflammatory cytokines interleukin-1 beta and TNF-alpha, combined with an excess of their natural inhibitors interleukin-1Ra and TNFsRp55, were seen in clinically asymptomatic HIV-1-positive African women but not in African women with AIDS or in HIV-negative controls. Circulating cytokine antagonists may play a clinical role in modulating cytokine-associated symptoms in the early phases of HIV infection.