Detection of histone-HA and histone-IAIP complexes in plasma and tissues of baboons challenged with a lethal dose of E coli. (A) Histone-IAIP (His-IAIP) complexes, (B) total IAIP, and (C) histones and/or nucleosomes were detected in plasma of baboons challenged with E coli by intravenous infusion. T0 is the time of blood collection before E coli challenge. Data are shown as mean ± SEM of 3 independent experiments using one-way ANOVA with Bonferroni’s multicomparison test. ****P < .0001, ***P < .0001, **P < .01, and *P < .05 compared with the time of blood collection before E coli challenge (T0). (D) Immunohistochemical detection of IAIP (red) and cit-H4 with an antibody detecting citrulline at residue 3 (Cit-H4, green) in kidney sections from septic baboons shows colocalization of the 2 proteins (yellow) with neutrophil extracellular traps (arrows). Magnification bar: 50 µm. (E) Colocalization for IAIP (green) and H4 (red; overlap, yellow) in areas showing tubular necrosis in the kidney from a septic baboon. Magnification bars: 100 µm. (F) Colocalization of HA (red) with H4 (green) in areas with tubular necrosis of the kidney from a septic baboon. Magnification bars: 100 µm.