[Anti-beta 2 glycoprotein I antibodies in systemic lupus erythematosus: a marker of thrombosis associated with a circulating anticoagulant].

An ELISA technique for the detection of anti-beta 2 glycoprotein I (beta 2gp I) antibodies was developed. Among 47 systemic lupus erythematosus patients, 17 had anti-beta 2gp I antibodies. These antibodies were statistically associated with anticardiolipin antibodies, lupus anticoagulant and thrombosis. Out of 18 patients with anticardiolipin antibodies without anti-beta 2gp I antibodies or lupus anticoagulant, only one had thrombosis (due to nephrotic syndrome). Therefore the presence of anti-beta 2gp I antibodies is a new immunologic marker of lupus patients with thrombosis. In addition, we propose that anti-beta 2gp I antibodies may be directly responsible for lupus anticoagulant activity.