PROCR and acute respiratory distress syndrome: We found that ARDS-developing mice have approximately 28.5 times more EPCR expression than uninfected mice; they showed more EPCR protein in their lungs than HP-developing mice, and TNF-stimulated PMLECs displayed an upregulation in EPCR expression compared to that of nonstimulated cells (NS) or cells stimulated with iRBCs, indicating that EPCR can contribute to ARDS progression.