A plasma coagulation defect in systemic lupus erythematosus arising from hypoprothrombinemia combined with antiprothrombinase activity.

By SAMUEL I. RAPAPORT, S r A BETH AMES AND BARBARA J. DUVALL C ONLEY AND HARTMANN’ first called attention to a plasma coagulation disturbance peculiar to patients with systemic lupus erythematosus or closely related dysproteinemias. Its characteristics are a long whole blood and/or recalcified plasma clotting time, a long Quick “prothrombin” time, and the presence of a circulating anticoagulant interfering with prothrombin conversion by either formed blood “thrcmboplastic” activity or tissue thromboplastin. The anticoagulant has no antithrombic activity and is not neutralized by protamine; thus, it is quite unlike heparin. The prolonged Quick “prothrombin” time was originally attributed to the anticoagulant’s ability to inhibit tissue thromboplastin. However, evidence that these patients may also develop true hypoprothrombinemia has gradually accumulated as they have been studied with more specific prothrombin technics.2 The child with systemic lupus erythematosus to he described in this paper had serious bleeding associated with a severe plasma coagulation disturbance. A profound hypoprothrombinemia was demonstrated by every technic used to measure prothrombin. The hypoprothromhinemia overshadowed evidence of the simultaneous presence of an anticoagulant which interfered with prothrombin conversion by either tissue or blood prothrombinase.* A comparison of these findings with those in the literature leads us to conclude that the plasma coagulation dist irbances of systemic lupus erythematosus usually stem from a mixture of anticoagulant activity and true hvpoprothrombinemia.