What are the target cells and receptors that are recognized by antiphospholipid antibodies?

The antiphospholipid syndrome (APS) is a noninflammatory autoimmune disease defined by the presence of antiphospholipid autoantibodies (aPL) in plasma of patients with venous and/or arterial thrombosis and/or recurrent complications of pregnancy. Animal studies in which antibodies isolated from patients with APS were injected into mice and hamsters suggest that there is a direct link between aPL and an increased risk of thrombosis and fetal loss. However, how these antibodies induce the increased risk is unknown and a subject of many speculations The most popular theory to explain the prothrombotic action of aPL is their ability to activate different cell types involved in the maintenance of the hemostatic balance. Many different receptors have been identified that are involved in the binding and activation of cells by the autoantibodies. In this overview, our present knowledge and the most important controversies on antiphospholipid antibody mediated cell activation are discussed.