Dual stimulation of neutrophils is required for optimal mediator release. Neutrophils were cultured for either 2 or 24 h in the absence of presence of different stimuli (GM-CSF (50 U/mL), fMLF (1 µM), TNF (1 ng/mL) and/or LPS (10 ng/mL). (A) NE was measured in culture supernatants collected 2 h after activation (n = 7). (B) Correlation between NE release and degranulation. Neutrophil degranulation was assessed by flow cytometry as shown in Figure 1. Data consist of 7 independent experiments, with multiple conditions in each experiment. (C) IL-8 was measured in culture supernatants collected 24 h after activation (n = 11). (D) Correlation between IL-8 release and degranulation. Neutrophil degranulation was assessed by flow cytometry as shown in Figure 1. Data consist of 11 independent experiments, with multiple conditions in each experiment. (A,C) Data are presented as means ± SD, * p < 0.05, ** p < 0.01, *** p < 0.001, one-way ANOVA with Tukey’s correction. (B,D) Linear regression was applied to determine R.