Thrombocytopenia results in PC-dependent lung hemorrhage after infection, with intact hemostasis in distant organs. Very low-PC, low-PC, and control mice were infected with K pneumoniae via the airways and euthanized at 12 or 44 hours. (A) Representative photographs of naive or infected lungs. (B) Representative photomicrographs of H&E-stained tissue sections of naive or infected lungs at 44 hours (original magnification ×4). (C) Lung bleeding was scored on H&E tissue sections by a pathologist blinded for groups. (D) Hb was measured in 50-fold diluted lung homogenates by light density at 410 nm. (E) Severity of inflammation was scored on H&E tissue sections. Data are expressed as box-and-whisker plots depicting the smallest observation, lower quartile, median, upper quartile, and largest observation. n = 8 mice per group. **P < .005 and ***P < .0005 vs control; #P < .05 and ##P < .005 vs low-PC. OD, optical density.