[Antiphospholipid antibodies. Review]

The antiphospholipid antibodies (APA), are immunoglobulins directed against anionic phospholipids that adopt a hexagonal configuration after incubation at 37 degrees C. They are usually IgG, IgM, IgA or a combination of them. Initially these antibodies were designated as "lupus anticoagulant", because they were found in patients with systemic lupus erythematosus, and because they prolong coagulation tests that need phospholipids in the system. The APA antibodies can be found associated with a variety of diseases, immunological, infectious, malignant disorders etc. They can also be drug related, can be found during pregnancy and even in non pregnant normal persons. The main clinical manifestations are thrombosis, thrombocytopenia and recurrent fetal losses. The diagnosis of APA is usually made, in the absence of antibodies against clotting factors, when a prolonged partial thromboplastin time can not be corrected with normal plasma. Prothrombin time, plasma recalcification time or the diluted Russell viper venom clotting time, are also used for the diagnosis. The antibodies and the specific phospholipid or phospholipids involved are usually demonstrated by enzymatic methods (ELISA). Depending on the clinical symptoms, the presence of APA can go without treatment or need anticoagulant or immunosuppressive therapy. Human endovenous immunoglobulin and plasmapheresis have also been used, especially during pregnancy.