IgE-induced blood coagulation alterations in the rabbit: consumption of coagulation factors XII, XI, and IX in vivo.

Intravenous administration of BSA into 3-month-old rabbits producing detectable anti-BSA antibody only of the IgE class of immunoglobulin induced a variety of intravascular blood coagulation alterations observed in the plasma 15 min after antigen challenge included: a) the intravascular consumption of intrinsic blood coagulation factors XII, XI, and IX and possibly the reduction in clottable fibrinogen; b) a significant prolongation of the activated partial thromboplastin time but not the prothrombin time; and c) the production of an inhibitor affecting the last stage of blood coagulation. The observed blood coagulation alterations were not caused by the manipulative procedures utilized, the presence of anti-BSA, IgG or IgM antibody, histamine-induced alterations in the vascular endothelium or the development of hypotensive shock. It is proposed that specific IgE antibody can induce directly or indirectly the activation of intrinsic blood coagulation in vivo.