Antiphospholipid antibodies (aPL) represent a spectrum of (apparent) phospholipid-binding antibodies. aPL include the false-positive serologic test for syphilis, the lupus anticoagulant, and the anticardiolipin antibody. A distinct clinical syndrome has been associated with these antibodies, the "antiphospholipid antibody syndrome," which is characterized by the triad of recurrent venous and arterial thrombosis, thrombocytopenia, and recur-rent fetal loss, as well as a number of other organ system manifestations. In addition to the recognition of newer clinical manifestations of this syndrome, understanding of the basic immunology and pathophysiology has changed dramatically during the last several years: antiphospholipid anti-bodies are now known to recognize two or more phospholipid-binding proteins rather than pure phospholipid, potentially explaining the diversity in clinical presentations and complications. Current therapies are based on long-term anticoagulation for prevention of recurrent thromboses and a combination of low dose aspirin with heparin during pregnancy. The discovery of beta2-glycoprotein I and other phospholipid-binding proteins as antibody epitope sites may lead to novel therapies in the near future.
