IL-12 production in response to SAC decreases with progression to disease. IL-12 p40 (open symbols, dotted lines) and IL-12 p70 (closed symbols, solid lines) production in whole blood cultures from 55 HIV-infected individuals on 20 hours culture in the presence of 0.008% SAC was plotted against CD4⁺ T-cell number as PB (A) or T-cell reactivity to CD3 MoAb in vitro25 (B). Correlations were analyzed with the Spearman's rank correlation test. Correlations of CD4⁺ T-cell counts with IL-12 p40 and with IL-12 p70 were R = .50, P < .005, and R = .44, P < .005, respectively. Correlations of T-cell reactivity with IL-12 p40 and with IL-12 p70 were R = .50, P < .005, and R = .45, P < .005, respectively.