The effect of ALG on coagulation and fibrinolysis

Rapid intravenous injection of ALG is known to induce an anaphylactoid reaction and platelet aggregation. It is also claimed to activate the coagulation system. In the present study, rapid intravenous injection of ALG in splenectomized dogs resulted in thrombocytopenia and decrease of fibrinogen. It was also found to increase the disappearance rate of ¹²⁵I-labelled fibrinogen. At the same time successively increasing levels of FDP were observed. The changes induced by ALG alone were significantly reduced by pretreatment of the dogs with Heparin, Trasylol or Aspirin. Protection was also given by thrombocytopenia. On the other hand, inhibition of the fibrinolytic system with AMCA resulted in formation of fibrin thrombi in the lung. It is suggested that ALG activates the coagulation system by trapping of platelets and leukocytes resulting in a vessel wall injury as well as an activation of the complement system.