Effects of estradiol and progesterone on markers of inflammatory cell activation. Normal neutrophils (1 × 10⁶ cells/mL) were incubated for 6 hours with estradiol, progesterone, or both in combination (10^-8 g/mL). Cells were then assessed for CD11b (A) using a PE-labeled mAb and the mean channel fluorescence analyzed using flow cytometry. □ indicates male (n = 8); and ▪ indicates female (n = 8). (B) ROI activity was assessed in neutrophils preincubated with sex steroids for 6 hours and then stimulated with DHR (baseline [BL]) alone or in addition to PMA (respiratory burst [RB]). Results were expressed as the Ln mean channel fluorescence ± SEM. (C) Results were also expressed as the Δ difference of the Ln mean channel fluorescence between DHR-treated cells with and without PMA stimulation. *P < .05 versus control (male, n = 8; female, n = 8). Error bars indicate mean ± SD.