Recurrent Thrombosis in a Young Woman With a Circulating Anticoagulant Directed Against Factors Xi and Xii

Abstract

A young woman with discoid lupus erythematosus and a potent circulating anticoagulant directed against factors XI and XII is described. The patient had no bleeding symptoms, but had had repeated episodes of venous thrombosis. The fibrinolytic activity of the vein walls was found to be decreased. It was apparent that a circulating anticoagulant against factors XI and XII will not prevent thrombus formation in a patient with low fibrinolytic activity of the vessel walls, which is known to predispose to thrombosis.

Circulating Anticoagulant Against Factors XI and XII Together with Massive Spontaneous Platelet Aggregation

“…As pointed out in the introduction most acquired inhibitors of coagulation are directed against factor VIII, factor IX or thromboplastin and such patients use to have a severe haemorrhagic disorder. In contrast Aberg & Nilsson (1972) recently dcscribed a young woman with discoid lupus erythematodes and a potent circulating anticoagulant directed against factors XI and XII. This patient had no bleeding symptoms but had had repeated episodes of thrombosis.…”

“…Two-stage method for assay of inhibitors against factor VIII and factor IX was determined as described by Aberg & Nilsson (1972).…”

“…In such patients severe bleeding symptoms occur. Antibodies against factors XI and XI1 are rare (Aberg & Nilsson 1972).…”