Antiphospholipid antibodies and the endothelium

Antiphospholipid antibodies (aPL) are related to a thrombophilic diathesis and display a pathogenic role. It has been suggested that aPL can interfere with endothelial cells (EC). Antiphospholipid antibodies react with EC mai nly through the binding to beta2-glycoprotein I (beta (2)GPI) adhered to en dothelial membranes. beta (2)GPI adheres to EC cell surfaces by means of th e PL-binding site that binds to heparin like structures and by specific rec eptor proteins. The formation of the complexes between beta (2)GPI and the specific antibodies activates EC and induces signalling events that upregul ate adhesion molecule, cytokine, and TF expression. The proadhesive and pro inflammatory endothelial phenotype is closely linked to a procoagulant acti vity.