RELATIONSHIP OF ANTI BETA(2)-GLYCOPROTEIN-I AND ANTI PROTHROMBIN ANTIBODIES TO THROMBOSIS AND PREGNANCY LOSS IN PATIENTS WITH ANTIPHOSPHOLIPID ANTIBODIES

The lupus anticoagulant (LA) and anticardiolipin antibodies (aCL) an c linically relevant because of their association with thrombosis and pr egnancy loss. The group of antiphospholipid antibodies (aPL) includes antibodies primarily directed against various phospholipid-binding pro teins, mainly beta(2)-glycoprotein I (beta(2)GPI) and prothrombin. Som e studies suggest that there is an association between the presence of anti beta(2)GPI antibodies (a beta(2)GPI) of IgG isotype and thrombos is. Therefore. aPL defined according to the plasma protein to which th ey are directed appear to be more appropriate for the evaluation of th eir clinical importance. Using home-made ELISAs we evaluated the prese nce of a beta(2),GPI and antiprothrombin antibodies (anti-II) of both isotypes (IgG and IgM) in a group of 233 patients with LA and/or aCL, Forty-four women had a history of pregnancy loss, 45 patients had a hi story of venous thrombosis (VT) and 32 of arterial thrombosis (AT). Pa tients from the autoimmune group (systemic lupus erythematosus land an tiphospholipid syndrome) had a higher prevalence of a beta(2)GPI and/o r anti-II than those from the miscellaneous group. In the univariate a nalysis, a significant association was shown between the presence of a beta(2)GPI-IgG (OR 3.2; 95% CI 1.5-6.6) and previous VT, but not AT. Anti-II were related to VT but the multivariate analysis showed that a beta(2)GPI-IgG are the only independent risk factor for VT (OR 3.0 95 % CI 1.3-6.2). The presence of a beta(2)GPI-IgM correlates well with a history of pregnancy loss (OR 2.6; 95% CI 1.1-6.1). The coagulation t ests profile showed that the clotting assays were more prolonged in pa tients having aCL, a beta(2)GPI or anti-II. But a higher prevalence of abnormal results was only found for the dilute Russell viper venom ti me in patients with VT, as compared to those without thrombosis (94.4% vs. 58.7%, p < 0.02). The measurement of a beta(2)GPI of both isotype s could help to identify aPL positive patients with a higher risk for thrombosis and pregnancy loss, although this association should be con firmed by prospective studies.