Beta-2 glycoprotein I–phosphatidylserine complex (β2GPI–phosphatidylserine complex)

The **Beta-2 glycoprotein I–phosphatidylserine complex** is formed when β2GPI, a highly glycosylated plasma glycoprotein, binds to phosphatidylserine exposed on the membranes of apoptotic or activated cells[1][2][3]. This interaction exposes new epitopes that are highly antigenic, leading to the development of autoantibodies notably in antiphospholipid syndrome (APS)[1][4][5]. The complex is central to clearance of apoptotic cells and regulation of coagulation and complement systems, but its presence also stimulates thrombogenesis and pathological immune responses in APS and supports the use of anticoagulant and immunomodulatory therapies. The β2GPI protein undergoes conformational changes upon binding phosphatidylserine, which have been implicated in its antigenicity and function[4][6]. It is a major biomarker and therapeutic target in APS, with safety challenges related to balancing thrombosis and bleeding risk in patients[1][5][6].

Other names

β2GPI–phosphatidylserine complexBeta-2 glycoprotein I–phosphatidylserine complexApolipoprotein H–phosphatidylserine complexβ2-glycoprotein I (when referring to the protein alone)Apo-H (when referring to β2GPI alone)

Inhibition of β2GPI–phospholipid autoantibody binding (experimental monoclonal antibodies) Anticoagulation (interrupts enhanced thrombotic risk produced by anti-β2GPI antibodies or the complex itself) Immunomodulation (hydroxychloroquine and others decrease autoantibody production or inflammatory sequelae)