Antiphosphatidylserine, IgA, IgG, IgM

An adjunct to β₂-glycoprotein and anticardiolipins in diagnosing aPS (antiphospholipid syndrome) for assessing thrombotic risk and other obstetric complications such as miscarriage or fetal growth restrictionAntiphospholipid antibodies are a heterogeneous group of immunoglobulins that bind to several anionic phospholipids, including cardiolipin and phosphatidylserine. High serum levels of antiphospholipid antibodies are frequently detected in patients with autoimmune (ie, SLE) and nonautoimmune diseases, as well as in apparently healthy individuals. These antibodies have been associated with an increased risk for recurrent arterial and venous thrombotic events, thrombocytopenia, and fetal loss. These manifestations are the main features of the antiphospholipid syndrome. Antiphospholipid antibodies are detected either by ELISAs using cardiolipin or other negatively-charged phospholipids as the antigen (anticardiolipin antibodies) or coagulation assays (lupus anticoagulants). Unlike cardiolipin, phosphatidylserine is a more physiologically relevant phospholipid due to its presence in cell membranes of endothelial cells and platelets and its role in the coagulation cascade. The detection of antiphosphatidylserine (aPS) antibodies by ELISA has been recommended for the serological diagnosis of antiphospholipid syndrome. Patients with positive reactions to both cardiolipin and phosphatidylserine are more likely to have clinical complications than those positive for only one. Higher prevalence and mean serum levels of antiphosphatidylserine antibodies have been reported in autoimmune patients. In addition, antiphosphatidylserine antibodies in SLE patients correlated with clinical manifestations of antiphospholipid syndrome and their pathogenic role has been demonstrated in a murine model.