Role of 2-glycoprotein I in the pathogenesis of the antiphospholipid syndrome

Antiphospholipid syndrome (APS) is typically characterized by increased levels of three classes of antiphospholipid antibodies, namely lupus anticoagulant, anti-beta 2-glycoprotein I (anti-beta 2GPI), and anticardiolipin antibodies. beta 2-Glycoprotein (beta 2GPI) is a phospholipid-binding protein composed of five domains (DI-V) and a major antigen in APS. beta 2GPI is expressed on the surfaces of several cell types, including endothelial cells, monocytes, trophoblast cells, and platelets. Its binding to the anti-beta 2GPI antibody triggers downstream signaling events and ultimately exerts a variety of cellular effects. beta 2GPI modulates hemostasis and the complement system, as well as playing an important role in APS-associated vascular injury. Therefore, studying beta 2GPI will help elucidate the pathogenesis of APS and improve the treatment of patients with this condition. This review will mainly focus on the structure and function of beta 2GPI, as well as its implication in the pathogenesis of APS.