ANTICARDIOLIPIN, ANTI-BETA(2)-GLYCOPROTEIN-I, ANTIPROTHROMBIN ANTIBODIES, AND LUPUS ANTICOAGULANT IN PATIENTS WITH SYSTEMIC LUPUS-ERYTHEMATOSUS WITH A HISTORY OF THROMBOSIS

Objective. To determine the clinical importance of anticardiolipin (aC L), anti-beta(2)-glycoprotein I (a beta(2)-GPI), antiprothrombin (aPT) , and lupus anticoagulant (LAC) antibodies in patients with systemic l upus erythematosus (SLE) with and without a history of thrombosis. Met hods. We studied 100 patients with SLE (32 with a history of thrombosi s), 27 patients with a lupus-like disease (9 with a history of thrombo sis), and 41 healthy volunteers. IgG and IgM aCL, antibodies to the pr otein cofactors (a beta(2)-GPI and aPT) were determined by ELISA. Eigh ty-six of 127 patients were also tested for LAC. Results. IgG aCL and LAC were associated with thrombosis but sensitivity (63 and 61%) and s pecificity (66 and 66%, respectively) of these tests were low. IgG and IgM a beta(2)-GPI were, respectively, 85 and 86% specific for a throm botic history, but sensitivity was very low (32 and 29%). High IgG aCL were associated with the presence of a beta(2)-GPI and were 85% speci fic for thrombosis. There was no significant association between IgG o r IgM aPT and thrombosis. Conclusion. Only high levels of IgG aCL and presence of LAC and/or a beta(2)-GPI are relevant in defining a thromb otic subset of patients with SLE. Longitudinal prospective studies are needed to investigate the predictive value of the different antiphosp holipid and protein cofactor antibodies.