Activation and consumption of Hageman factor in the anaphylactic shock of the rat.

In the early stages of anaphylactic shock of rats pretreated with Bordetella pertussis vaccine, a prompt and parallel activation of the factor XIIa-dependent intrinsic coagulation, kinin generation, and fibrinolytic acticity was observed. The coagulation studies, the similarity of anaphylactic results with those produced by a single injection of ellagic acid, and the effective inhibition of the anaphylactic and the ellagic acid-induced activation of these pathways by lysozyme all suggest that factor XII itself becomes activated in rat anaphylaxis. As the reaction proceeded, considerable anticoagulant activities emerged, but the bradykinin and the plasminogen activator levels even further increased. During the first 10 min of anaphylactic shock, factor XII was partly consumed and this was prevented by epsilon-aminocaproic acid infusion. The results show that in pathological conditions such as anaphylaxis there is an intimate in vivo interaction among the three factor XIIa-dependent pathways.