The annexin V IgG antibody test is an assay used to detect the presence of IgG class autoantibodies directed against annexin V, a cellular protein involved in regulating apoptosis and coagulation. This test is primarily utilized to evaluate autoimmune disorders, particularly those associated with an increased risk of thrombosis and recurrent pregnancy loss.
Annexin V is a phospholipid-binding protein that plays a crucial role in maintaining cellular homeostasis, particularly in programmed cell death (apoptosis) and anti-thrombotic processes. It binds with high affinity to phosphatidylserine, a phospholipid that becomes externalized on the surface of apoptotic cells. Through this binding, Annexin V forms a protective shield over these phospholipids, effectively preventing the activation of the coagulation cascade. Autoantibodies against Annexin V disrupt this protective function, potentially exposing procoagulant phospholipids to circulating clotting factors, which leads to a hypercoagulable state.
Elevated levels of Annexin V IgG antibodies have been observed in individuals with antiphospholipid syndrome (APS), which is characterized by thrombosis, recurrent fetal loss, and the presence of antiphospholipid antibodies. Their presence has also been studied in patients with systemic lupus erythematosus (SLE), where they may work synergistically with other autoantibodies to heighten thrombotic risk.
Research continues to investigate the prognostic and diagnostic importance of Annexin V antibodies in various clinical contexts, including cardiovascular disease, autoimmune disorders, and obstetric complications.
