Antiphospholipid syndrome

**Definition:** Antiphospholipid syndrome, also known as Hughes syndrome, is a systemic autoimmune condition characterised by the presence of antiphospholipid antibodies (aPL) in the serum of patients with thrombotic events and/or recurrent pregnancy complications.

**Long definition:** The antiphospholipid syndrome (APS) is characterized by venous and/or arterial thrombosis, recurrent pregnancy loss and the presence of antiphospholipid antibodies. The antiphospholipid antibodies (anticardiolipin, anti-bêta2GPI antibodies, lupus anticoagulant) interacting with various coagulation proteins, platelets or endothelial cells may contribute to disease pathogenesis. Incidence remains unknown, however the reported prevalence of antiphospholipid antibodies in the general population is low (1-4.5%) and increases with age. The main clinical manifestations associated with APS are thromboses, pregnancy morbidity, thrombocytopenia, neurological symptoms, livedo reticularis, hemolytic anemia. The antiphospholipid antibodies have been detected in approximately 1/3 of the patients with systemic lupus erythematosus (SLE). High anticardiolipin antibodies titers, lupus anticoagulant and especially anti-bêta2GPI antibodies are important predictors of APS clinical manifestations in SLE patients. The management of thrombosis includes long-term, high-intensity warfarin therapy [International Normalized Ratio (INR superior or equal to 3)]. For pregnancy morbidity the recommended therapy is low-dose aspirin (80 mg/day) plus subcutaneous unfractionated heparin or low-molecular-weight heparin.