ANTI-BETA(2)-GLYCOPROTEIN-I ANTIBODIES - DETECTION AND ASSOCIATION WITH THROMBOSIS

It has been demonstrated that antiphospholipid antibodies (aPL) recogn ize epitopes formed by anionic phospholipids and protein cofactors. be ta 2 glycoprotein I (beta(2)GPI) is accepted as the cofactor of antica rdiolipin antibodies (aCL). In the present study we explored the prese nce and clinical associations of anti beta(2)GPI antibodies of IgG iso type (a beta(2)GPI-IgG), measured by ELISA. We studied sera from 169 p atients with aCL and/or lupus anticoagulant (LA), including 52 patient s with systemic lupus erythematosus and 49 with primary antiphospholip id syndrome (PAPS). We found 31.9% positive sera for a beta(2)GPI-IgG in the whole population and 48.6% in the aCL-IgG(+) group. There was a good correlation between the titre of aCL-IgG and the optical density for a beta(2)GPI-IgG (r = 0.69, P < 0.01). The presence of a beta(2)G PI-IgG was associated with the presence of aCL-IgG (P < 0.0001) and LA (P < 0.0005). However, none of 23 LA (+) patients without aCL had a b eta(2)GPI-IgG. We found a statistically significant association betwee n the presence of a beta 2GPI-IgG and a history of venous thromboembol ism (VTE) in our patients (P < 0.005). This association was observed i n PAPS (P < 0.05) but not in secondary antiphospholipid syndrome (SAPS ). Our study confirms that some aPL(+) sera react with beta(2)GPI in s pecial experimental conditions. In addition, the presence of these ant ibodies is associated with a history of VTE.