Beta-2-glycoprotein 1 (B2GP1) (B2GP1)

Beta-2-glycoprotein 1 (B2GP1), also known as apolipoprotein H, is a 50 kDa plasma glycoprotein that plays a critical role in the regulation of blood coagulation and the immune system. It is composed of five complement control protein (CCP) domains and exists in both circular and elongated conformations. B2GP1 is the primary autoantigen in antiphospholipid syndrome (APS), an autoimmune disorder characterized by recurrent thrombosis and pregnancy complications. In APS, pathogenic autoantibodies typically target Domain I of the elongated form of B2GP1, leading to cellular activation and a prothrombotic state. The protein also interacts with anionic phospholipids, DNA, and neutrophil extracellular traps, further contributing to its role in inflammation and autoimmunity. While current management relies on anticoagulants like warfarin and heparin, emerging therapies aim to specifically target B2GP1 or the autoantibodies directed against it. These include monoclonal antibodies, B-cell depleting agents, and complement inhibitors designed to mitigate the inflammatory and thrombotic cascades initiated by B2GP1-antibody complexes.

Other names

Apolipoprotein HAPOHB2GPIBeta-2-GPIActivated protein C cofactor

Inhibition of autoantibody binding to B2GP1, depletion of B cells or plasma cells producing anti-B2GP1 antibodies, or inhibition of downstream complement activation triggered by B2GP1-antibody complexes.