LUPUS ANTICOAGULANT ACTIVITY OF SOME ANTIPHOSPHOLIPID ANTIBODIES AGAINST PHOSPHOLIPID BOUND BETA(2)-GLYCOPROTEIN-I

Aims-To determine whether beta2 glycoprotein I (beta2GPI) dependent anticardiolipin (aCL) antibodies detected in solid phase enzyme linked immunosorbent assays can also have lupus anticoagulant activity. Methods-Six anticardiolipin antibodies were affinity purified from patients with these antibodies and lupus anticoagulant activity in their plasma. Results-The anticardiolipin antibodies bound only to anionic phospholipids in the presence of beta2GPI and bound to beta2GPI in the absence of phospholipids. Four out of six had lupus anticoagulant activity in the dilute Russell viper venom time test. Conclusions-The results show that some beta2GPI dependent aCL are lupus anticoagulants. It is unclear why only some should have lupus anticoagulant activity while others do not.