Novel insights into associations of antibodies against cardiolipin and beta2-glycoprotein I with clinical features of antiphospholipid syndrome

Antiphospholipid syndrome (APS) is a clinical autoimmune disorder characterized by arterial and/or venous thrombosis and/or pregnancy morbidity, associated with the persistence of lupus anticoagulant or anticardiolipin (aCL) antibodies. Accumulating evidence indicates that phospholipid binding protein, beta2-glycoprotein I (β2GPI) represents the major target antigen for antiphospholipid (aPL) antibodies and plays a role in the pathogenesis of APS. It is widely accepted that aPL antibodies detected by conventional solid phase assays in patients with APS are mainly directed against a complex of aCL and anti-β2GPI, although antibodies against β2GPI protein can now also be detected by specific ELISA using purified proteins in solid phase. Despite the fact that these antibodies are not listed in the new diagnostic criteria, a high specificity of anti-β2GPI assay for the clinical features of APS was established. During the last decade, numerous studies have investigated the clinical link between aCL and/or anti-β2GPI antibodies and diverse features of APS. This manuscript reviews the current studies published recently in this field and discusses the relationship between the existence of aCL and anti-β2GPI antibodies and the main and unusual manifestations of APS.