ANTIPHOSPHOLIPID ANTIBODIES ARE NOT PRESENT IN THE MEMBRANE OF GEL-FILTERED PLATELETS OF PATIENTS WITH IGG ANTICARDIOLIPIN ANTIBODIES, LUPUS ANTICOAGULANT AND THROMBOSIS

To explore the possibility of an interaction between platelets and ant iphospholipid antibodies and its relationship with thromboembolic even ts, platelets from six patients with IgG anticardiolipin antibodies, l upus anticoagulant and thrombosis were isolated by gel filtration. Fiv e patients had primary antiphospholipid syndrome and one had a form se condary to systemic lupus erythematosus. Two patients had mild thrombo cytopenia. The six platelet membrane eluates contained less than 1.09 GPL units of anticardiolipin antibodies and displayed no lupus anticoa gulant activity. Similarly, lysates of disrupted platelets did not sho w anticardiolipin or lupus anticoagulant activity. These results sugge st that antiphospholipid antibodies do not interact with circulating p latelets, at least in patients on oral anticoagulant treatment with no evidence of acute thrombosis.