Innate immunity and coagulation

Infection frequently elicits a coagulation response. Endotoxin triggers the formation of tissue factor initiating coagulation, down regulates anticoagulant mechanisms including the protein C pathway and heparin‐like proteoglycans and up regulates plasminogen activator inhibitor. The overall physiological result of this is to promote coagulation through enhancing initiation, suppressing negative regulation and impairing fibrin removal. The response to infection also leads to tissue destruction. Nucleosomes and histones released from the injured cells trigger further inflammation, protection from the pathogen but further tissue injury leading to multi‐organ failure. Such a complex response to infection presumably arises due to the role of coagulation in the control and clearance of the infectious agent.