Inhibiting ROS protects mice from HIT-induced thrombosis but not thrombocytopenia. FcγRIIa⁺/hPF4⁺ double transgenic mice were injected IV with normal IgG or KKO. Heparin was injected intraperitoneally. Representative images and graphical representation of fluorescence intensity from platelet accumulation in mouse lungs from mice treated with normal IgG, KKO, and vehicle control, (A) KKO and DPI (n = 4), or (D) KKO and GSK2795039 (n = 3). (B,E) Platelet counts are represented as percentage of platelets relative to basal levels (n = 4). Rectal temperature of FcγRIIa⁺/hPF4⁺ mice treated with KKO or normal IgG, with and without (C) DPI (n = 4) or (F) GSK2795039 (n = 3). (G) Confocal images of lung lobe from mice treated with heparin and KKO, KKO and GSK2795039, or control IgG. 4′,6-Diamidino-2-phenylindole (DAPI)-stained nuclei (blue), platelet-rich thrombi (red). Scale bar, 1 mm.