Molecular pathogenesis of the antiphospholipid syndrome

The antiphospholipid (aPL) syndrome is an acquired autoimmune disorder of unknown etiology in which patients present with thrombosis together with laboratory evidence for antibodies in blood that recognize anionic phospholipid-protein complexes. The main antigenic target for the aPL antibodies has been identified to be beta(2) glycoprotein I (beta(2)GPI), a phospholipid-binding protein. The high affinity of aPL antibody-beta(2)GPI complex for phospholipid membranes seems to be a critical step in the mechanism of this disease. This review focuses on some of the major mechanisms that have been proposed to explain this disorder.