Effects of intravascular clotting on the activation of the complement system: The role of the platelet.

Total hemolytic complement activity and the third component of complement were found to be significantly depressed in vivo in rabbits following the induction of disseminated intravascular coagulation by both thrombin and thromboplastin. Production of severe thrombocytopenia by the administration of platelet antiserum prior to the infusion of thrombin or thromboplastin partially prevented complement activation. The data show that, when clotting is triggered, complement activation takes place and that platelets are required to some extent for this reaction.