Antiphospholipid Syndrome

The antiphospholipid syndrome (APS) is an autoimmune disorder characterized by thrombosis, pregnancy losses, and the presence of at least one of three antiphospholipid antibodies. However, it has been acknowledged that the clinical spectrum of APS is much wider, including systemic and organ-specific manifestations. Moreover, the presence of more than 20 antiphospholipid antibodies has been recognized, some of which may participate in the pathogenesis of APS although not included as criteria.Our knowledge and understanding of the etio-pathogenesis of APS has increased tremendously, as the effects of antiphospholipid antibodies, mainly the anti-B2GPI-B2GPI immune complexes, were elucidated. The latter bind to different cells (i.e., monocytes, endothelial cells, and trophoblasts), recruit cell surface receptors, and subsequently induce intracellular signaling. Additionally an arsenal of environmental factors as infectious agents and vitamin D has been associated with the presence of antiphospholipid antibodies and overt APS. It seems therefore that in APS both thrombotic and immune-mediated mechanisms play a part and may be considered as candidates for targeted therapeutic interventions.