Luminal bound histones colocalize with areas of BBB breakdown and coagulopathy. (A) Histone endothelial membrane staining (black arrows) colocalizing with fibrinogen extravasation (blue arrow), which is indicative of BBB breakdown. (B) Strong association between the extent of histone endothelial membrane staining and the presence of fibrinogen extravasation, determined by ordinal logistic regression. (C) Histone membrane staining (black arrows) colocalizing with thrombosis (blue arrow). (D) Histone membrane staining (black arrow) colocalizing with a ring hemorrhage (edge demarcated by dotted line). Red staining is to anti-H3 antibody using Vector Red and brown staining is to antifibrinogen antibody using 3,3′-diaminobenzidine. Images were acquired at ×600 using an oil immersion lens.