Antiprothrombin antibodies: detection and clinical significance in the antiphospholipid syndrome.

ANTIPHOSPHOLIPID antibodies have been associated with a variety of clinical phenomena, including arterial and venous thrombosis, thrombocytopenia, and obstetric complications. The term ‘‘antiphospholipid syndrome’’1 is used to link a variety of thromboembolic events to antibodies against specific proteins involved in blood coagulation. Thrombotic events are reported in approximately 30% of patients with antiphospholipid antibodies,2,3 with an overall incidence of 2.5% patients/yr.4 Deep vein thrombosis of the legs and/or pulmonary embolism account for about two thirds of the thrombotic events, and cerebral arterial thrombosis are the most common arterial complications.2,3 Obstetric complications include recurrent spontaneous miscarriages, fetal deaths, or fetal growth retardations.5 Women with antiphospholipid antibodies are particularly prone to second or early third trimester fetal deaths.6 Hypoxia secondary to spiral arterial vasculopathy is considered to be the cause of the obstetric events.7 A variable degree of thrombocytopenia is reported in as many as 20% to 25% of patients.8 Thrombocytopenia is generally mild and seldom associated with bleeding complications; only 5% to 10% of patients are severely thrombocytopenic (,50 3 109 platelets/L).8 Less commonly, hemolytic anemia, livedo reticularis, skin necrosis, dementia or neuropsychiatric events, and the so-called ‘‘catastrophic’’ antiphospholipid syndrome are included in this picture.8 Two types of antiphospholipid syndrome have been described: the ‘‘primary’’ syndrome, which occurs in the absence of an underlying disease,9 and the ‘‘secondary’’ syndrome, which is related to systemic lupus erythematosus, other autoimmune or neoplastic diseases, or other pathological conditions.10