Antiphospholipid antibodies bind to activated but not resting endothelial cells: Is an independent triggering event required to induce antiphospholipid antibody-mediated disease?

Abstract

Introduction: Antiphospholipid antibodies (aPL) cause thrombotic disease and recurrent pregnancy loss. Despite their name it is now clear that the antigen for most antiphospholipid antibodies is the phospholipid-binding protein β2 glycoprotein I (β2GPI). However, β2 glycoprotein I is only antigenic for antiphospholipid antibodies when the protein is immobilised on a suitable surface such as phosphatidyl serine. It has been suggested that antiphospholipid antibodies bind to β2 glycoprotein I on the surface of resting endothelial cells and this in turn leads to endothelial activation and the initiation of thrombosis. However, as phosphatidyl serine is absent from resting endothelial cell membr..