Links between the immune and coagulation systems: How do "Antiphospholipidantibodies" cause thrombosis?

Inflammation and immune activation have been associated with thrombosis in a number of settings. We have been interested in the question of how the pr esence of a type of autoantibody, so-called "antiphospholipid" antibody, le ads to thrombosis. Several mechanisms have been proposed including modulati on of tissue factor expression, enhancement of procoagulant binding to plat elets, and interference with antithrombotic mechanisms. We developed a cell -based model of coagulation that, unlike current coagulation assays, reflec ts some of the in vivo activities of "antiphospholipid" antibodies. "Antiph ospholipid" antibodies against the phospholipid-binding protein beta-2-glyc oprotein-1 enhance thrombin generation in this model system, primarily by e nhancing procoagulant reactions on tissue factor-bearing cells.