Lupus anticoagulant autoantibody induces apoptosis in umbilical vein endothelial cells: involvement of annexin V.

The effects of lupus anticoagulant (LAC) on cultured human umbilical vein endothelial cells were studied. All five monoclonal antibodies from a patient with systemic lupus erythematosus (SLE), as well as plasma samples with LAC activity from six SLE patients, induced apoptosis. Anti-annexin V IgG also induced apoptosis. Since monoclonal antibodies and plasma from SLE patients had an affinity for annexin V, an endothelial apoptosis pathway mediated by annexin V was suggested as the molecular pathogenesis of the hemostatic derangement associated with LAC.