Activation Product, Factor IX, Serum Thrombotic Accelerator Activity, and Serum-induced Thrombosis*

Abstract

The thrombogenicity of infusions of glass-contacted normal and Factor IX-deficient human serum in rabbits and the AP and Factor IX content of these infusates were determined. Glass-contacted Factor DC-deficient serum was markedly less thrombogenic than normal human serum. The thrombogenicity of glass contacted Factor IX -deficient serum did not correlate with its level of A P. Although elaboration of serum thrombotic accelerator (STA) activity is dependent on the contact activation steps involved in the formation of intrinsic thromboplastin, STA activity cannot be equated with the activity measured by the one-stage partial thromboplastin assay of AP. Thus, STA activity is not the in vivo manifestation of AP. Factor IX, or an associated moiety in serum, plays a critical role in the formation of stasis thrombi induced by infusions of human serum.