A single dose of EPCR-blocking mAb attenuates joint bleeding and swelling in hemophilia A mice injured with a needle puncture. FVIII^−/− mice were administered with either EPCR-blocking (green circles) or EPCR-nonblocking mAb (red squares) (1 mg/kg). Twenty-four hours later, joint bleeding was induced with a needle puncture. Mice were monitored for 14 days to evaluate VBS (A) and changes in joint diameter (B). At the end of 14 days, mice were killed, and the limbs were photographed after removing overlying skin (C). UN, uninjured; I, injured. Data are mean ± SEM (n = 10 to 11 mice/group) (A-B). *P < .05; **P < 0.01; ***P < .001. (C) Pictures are representative images.