Fatal hemorrhagic diathesis associated with mild factor IX deficiency in pl/J mice

Surgical implantation of devices into the abdomen of PL/J mice was associated with fatal hemorrhage at 9 to 11 d after surgery. Coagulation profiles were evaluated to determine the underlying cause of this effect. The mean activated partial thromboplastin time (aPTT) of untreated PL/J mice was significantly higher than that of BALB/cByJ and C57BL/6J strains. The addition of human plasmas deficient in factors VIII, XI, or XII, prekallikrein, or high molecular-weight kininogen corrected the elevated aPTT of PL/J mice, but correction did not occur when factor IX-deficient human plasma was added. When compared to an assigned factor IX activity of 100% for pooled plasma from BALB/cByJ mice, C57BL/6J and PL/J mice revealed percent activities of 67% and 16%, respectively. PL/J mice could represent a new model for the study of pathogenesis and therapy of mild factor IX deficiency that is expressed and becomes clinically apparent secondary to major surgery.