PLASMA-LEVELS OF LIPOPROTEIN(A) ARE ELEVATED IN PATIENTS WITH THE ANTIPHOSPHOLIPID ANTIBODY SYNDROME

The mechanisms underlying clinical abnormalities associated with the a ntiphospholipid antibody syndrome (APAS) have not been elucidated. We measured plasma levels of lipoprotein(a) [Lp(a)], the active form of p lasminogen activator inhibitor (active PAI), thrombin-antithrombin m c omplex (TAT) and soluble thrombomodulin (TM), to investigate the relat ionship of these factors to thrombotic events in APAS. Mean plasma lev els of Lp(a), TAT, active PAI and TM were all significantly higher in patients with aPL than in a control group of subjects. Plasma levels o f Lp(a) and active PAI were significantly higher in patients with aPL and arterial thromboses than in patients with aPL but only venous thro mboses. There was a significant correlation between plasma levels of L p(a) and active PAI in patients with aPL. These findings suggest that patients with aPL are in hypercoagulable slate. High levels of Lp(a) i n plasma may impair the fibrinolytic system resulting in thromboses, e specially in the arterial system.