Haemostatic abnormalities in systemic lupus erythematosus.

Coagulation studies were performed in 112 consecutive patients with systemic lupus erythematosus (SLE). Abnormalities of haemostatic function occurred frequently and 96 abnormalities occurred in 64 of 112 (57 per cent) patients. Eighteen patients (16 per cent) had thrombocytopenia, 19 (16.9 per cent) had circulating anticoagulants and 24 had decreased antithrombin III levels. Abnormalities of fibrinogen were found in 28 patients (23 per cent), and abnormalities of platelet factor 3 and 4, indicating in vivo platelet activation occurred in seven patients. In 25 patients two or more abnormalities were detected simultaneously. No haemostatic abnormalities were detected in any of the 50 healthy volunteers who served as controls. Only one patient with thrombocytopenia had petechiae. None of the other patients, even those with multiple defects bled significantly, but several patients had vasculitis and/or phlebitis. There was no correlation between disease activity of SLE and the presence of haemostatic abnormalities, nor was there an association between these abnormalities and specific clinical haematologic manifestations.