Review ArticleAnnexin A2 autoantibodies in thrombosis and autoimmune diseases

•Annexin A2 is involved in fibrinolysis, inflammation, and endocytosis/exocytosis.•Anti-annexin A2 antibodies have been reported in thrombosis and APS.•Annexin A2 and anti-annexin A2 antibodies are involved in the pathogenesis of APS.•Anti-annexin A2 antibodies represent a new biomarker in thrombosis and APS.

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by arterial, venous or small-vessel thrombotic events, and recurrent miscarriages or fetal loss. APS diagnosis is based on the repeated detection of anti-phospholipid (PL) antibodies (Ab), typically associated with anti-β2 glycoprotein I (β2GPI)-Ab. Recent studies suggest that anti-β2GPI Ab activity involves a protein complex including β2GPI and annexin A2 (ANXA2). Anti-ANXA2 Ab recognizes this complex, and these Ab can effectively promote thrombosis by inhibiting plasmin generation, and by activating endothelial cells. Therefore, anti-ANXA2 Ab represent a new biomarker, which can be detected in up to 25% of APS patients. Moreover, anti-ANXA2 Ab have been detected, in thrombotic associated diseases including pre-eclampsia, in other autoimmune diseases, and in cancer.