These tests detect the presence of three classes (IgG, IgM, and/or IgA) of cardiolipin antibodies. Produced by the immune system in response to a perceived threat, these proteins are the most common antiphospholipid antibodies. They are acquired autoantibodies that can affect the body’s ability to regulate blood clotting. Although IgA antibodies can be measured by many commercially available laboratory tests, their significance…These tests detect the presence of three classes (IgG, IgM, and/or IgA) of cardiolipin antibodies. Produced by the immune system in response to a perceived threat, these proteins are the most common antiphospholipid antibodies. They are acquired autoantibodies that can affect the body’s ability to regulate blood clotting. Although IgA antibodies can be measured by many commercially available laboratory tests, their significance remains unclear and the current UK guidelines do not consider them to be diagnostic for antiphospholipid syndrome. Cardiolipins, and other related phospholipids, are lipid molecules normally found in cell membranes and platelets. They play an important role in the blood clotting process. When antibodies are produced against cardiolipins, they increase the risk of developing recurrent blood clots (thrombi) in arteries and veins. There is a stronger association for IgG antibodies and venous thrombosis (e.g. deep vein thrombosis), whereas both IgG and IgM may be seen in arterial clots, including acute stroke. Cardiolipin antibodies are also associated with thrombocytopenia, recurrent miscarriages (especially in the 2nd and 3rd trimester), and with premature labour and pre-eclampsia. Cardiolipin antibodies are frequently seen with autoimmune disorders, such as Systemic Lupus Erythematosus (SLE), and with other antiphospholipid antibodies, such as lupus anticoagulant. They may also occur temporarily in patients with acute infections, HIV/AIDS, some cancers, with drug treatments (such as phenytoin, penicillin, and procainamide), and asymptomatically in the elderly. When a patient has thrombi formation, recurrent miscarriages, thrombocytopenia, cardiolipin antibodies, and/or another antiphospholipid antibody, they may be diagnosed with Antiphospholipid Syndrome (APS). APS can be primary with no underlying autoimmune disorder, or secondary, existing with a diagnosed autoimmune disorder. See MoreSee Less
