Antiphospholipid Syndrome (APS) is an autoimmune disorder in which the body recognizes certain normal components of blood and/or cell membranes as foreign substances and produces antibodies against them. Patients with these antibodies may experience miscarriages and blood clotting disorders, including heart attacks and strokes. APS may occur in people with systemic lupus erythematosus and other autoimmune diseases, or in otherwise healthy individuals.