The most common factor-specific coagulation inhibitor is anti-factor VIII. This inhibitor is associated with the condition, "acquired hemophilia A." Anti-factor VIII interferes with the activity of factor VIII, which then leads to hemorrhagic complications. When anti-factor VIII binds to factor VIII, the factor VIII is no longer available to participate in the normal coagulation cascade, thus preventing the formation of a proper secondary hemostatic plug. This is demonstrated in vitro in the clinical laboratory with a prolonged activated partial thromboplastin time (aPTT) test.
Other reported factor-specific coagulation inhibitors include anti-factors II, V, VII, IX, X, XI, XII and XIII. Factor-specific antibodies may occur in association with post-partum periods, immunological problems, and aging.
