Elevated serum levels of antiphospholipid antibodies, thrombosis and/or pregnancy morbidity (miscarriages, recurrent fetal loss) are the major features of the antiphospholipid syndrome (APS). Antiphospholipid antibodies are a heterogeneous family of autoantibodies thought itplays an active role in the development of thrombosis in patients with APS. These antibodies react with negatively charged phospholipids, phospholipid/protein complexes, and certain plasma proteins presented on suitable surfaces (that is, activated cell membranes, oxygenated polystyrene). Most antiphospholipid antibodies from APS patients require the presence of certain plasma proteins for optimal phospholipid binding activity. β2-glycoprotein I (β2GPI), a phospholipid-binding protein, is now recognized as the most clinically relevant antigenic target for antiphospholipid antibodies. Antiβ2GPI antibodies are more specific for thrombosis (and APS) than anticardiolipin (aCL) antibodies. Recent prospective studies have shown that β2GPI-dependent aCL and antiβ2GPI antibodies were significant predictors of arterial thrombosis (myocardial infarction and stroke) in men. β2GPI has natural anticoagulant properties but it may also bind to oxidized low-density lipoprotein (oxLDL) to neutralize its pro-inflammatory effects and possibly to promote its clearance. Circulating oxLDL/β2GPI complexes are immunogenic and anti-oxLDL/β2GPI antibodies accelerate the development of autoimmune-mediated thrombosis and atherosclerosis.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)