%0 Journal Article
%T In vitro effect of anti-¦Â2 glycoprotein I antibodies on P-selectin expression, a marker of platelet activation
%A A. Bontadi
%A A. Ruffatti
%A S Giannini
%A E. Falcinelli
%J Reumatismo
%D 2012
%I PAGEPress Publications
%R 10.4081/reumatismo.2012.35
%X Antiphospholipid antibodies (aPL) associated with thromboembolic events and/or pregnancy morbidity characterize the so-called antiphospholipid syndrome (APS). Beta2glycoprotein I (¦Â2GPI) is the main target antigen for aPL, but the pathogenic role of anti-¦Â2GPI antibodies (a¦Â2GPI) is still unclear. Some authors assume they play a role in activating platelets. We evaluated the effects of a¦Â2GPI antibodies on platelet P-selectin expression. A¦Â2GPI antibodies in the plasma of a pregnant APS patient were isolated by affinity chromatography at two different stages (catastrophic and quiescent) of the disease. Gel filtered platelets (100 x 109/L) from healthy volunteers were incubated with ¦Â2-GPI (20 ¦Ìg/mL) and with different concentrations (5. 25 and 50 ¦Ìg/mL) of a¦Â2GPI antibodies. P-selectin surface expression on platelets was assessed by flow cytometry using a specific fluorescent antibody directed against P-selectin. A¦Â2GPI antibodies induced platelet activation only in the presence of thrombin receptor activator for peptide 6 (TRAP-6), a platelet agonist, at a subthreshold concentration. A¦Â2GPI antibody enhancement on platelet surface P-selectin expression was stronger in the catastrophic than in the quiescent phase of the disease (47 vs 15%). TRAP-6 dependent platelet activation by a¦Â2GPI antibodies is consistent with the ¡°two hit¡± pathogenetic hypothesis for thrombosis. A¦Â2GPI antibodies induce higher platelet P-selectin expression during the active rather than the acute phases.
%K Anti-¦Â2Glicoprotein I antibodies
%K P-selectin
%K Platelet activation
%K Antiphospholipid syndrome
%U http://www.reumatismo.org/index.php/reuma/article/view/545