Platelet-HMGB1 promotes ROS production but not NETs formation in neutrophils. (A-B) Platelets were isolated from HMGB1 Flox and HMGB1 PF4 mice. Twenty million platelets were treated with collagen (0.5 mM) or thrombin (0.2 U/mL) for 2 minutes and incubated with 1 million isolated WT neutrophils for 5 minutes. Representative flow cytometry histograms depict the ROS generations in neutrophils in the coculture with (A) collagen- or (B) thrombin-stimulated platelets. The histograms were representative of 4 experiments. (C) MPO-DNA complex levels in the peritoneal cavity. MPO-DNA complex levels in peritoneal lavage fluid were assessed in WT, HMGB1 Flox, and HMGB1 PF4 mice at 18 hours after CLP. Data represent means ± SD from 8 mice per group.