PROTEIN S AND ANTICARDIOLIPIN ANTIBODIES IN PATIENTS WITH LUPUS ANTICOAGULANT WITH OR WITHOUT THROMBOSIS

Arterial and venous thrombosis frequently occur in patients with lupus anticoagulant. We investigated in patients with lupus anticoagulant the possible association between protein S:Ag deficiency and/or anticardiolipin antibodies and a history of thrombosis. In 27 patients (8 with and 19 without a history of thromboembolic disease) free protein S:Ag was determined with immunoelectrophoresis in PEG 8000 precipitated plasma. Anticardiolipin antibodies were measured in 22 patients (10 with thromboembolism) by means of a solid phase radioimmunoassay. Free plasma protein S:Ag was normal or elevated in 25 patients and slightly decreased (protein S:Ag 67%) in 2 patients without thromboembolism. 2-dimensional electrophoresis revealed a normal distribution of the free and of the complexed form of protein S:Ag. Anticardiolipin antibodies were found in 6 out of 10 patients with a history of thrombosis (5 of 7 with venous thrombosis, 1 of 1 with cerebral infarction , none of 2 with combined venous and arterial thromboembolism) and in 4 out of 12 patients without a history of thrombosis. We conclude 1. the thrombophilic state in patients with lupus anticoagulant cannot be explained by a reduction of protein S:Ag, and 2. there seems to be no correlation between the presence or absence of anticardiolipin antibodies and the development of thromboembolic disease.