The symptoms associated with antiphospholipid antibody syndrome are caused by abnormal blood clots that occur when there is production of antibodies that damage phospholipids in the body. Phospholipids are needed in blood clotting whereas antibodies protect the body against bacteria and viruses. In severe cases, the abnormal blood clots can obstruct flow of blood to the affected organ and subsequently cause symptoms, such as high blood pressure, lung problems, heart damage, stroke, and kidney failure.