Lupus anticoagulant

Lupus anticoagulant (also known as lupus antibody, LA, LAC, or lupus inhibitors) is an immunoglobulin that binds to phospholipids and proteins associated with the cell membrane. Lupus anticoagulant is a misnomer, as it is actually a prothrombotic agent. Lupus anticoagulant antibodies in living systems cause an increase in inappropriate blood clotting. The name derives from their properties in vitro, since in laboratory tests, these antibodies increase aPTT. Investigators speculate that the antibodies interfere with phospholipids used to induce in vitro coagulation. In vivo, the antibodies are thought to interact with platelet membrane phospholipids, increasing adhesion and aggregation of platelets, which accounts for the in vivo prothrombotic characteristics.