Clinical features and pathogenesis of catastrophic antiphospholipid syndrome.

The concept of antiphospholipid syndrome (APS) has been established (1). It is well-known that one of the clinical features in APSis arterial or venous thrombosis, and that the specificity of so-called antiphospholipid antibodies have diversity against their epitopes, as so-called antiphospholipid antibodies react to phospholipids as well as plasma proteins such as p2-glycoprotein I and prothrombin (2-5). Antiphospholipid antibodies have been reported to be one of the acquired risk factors against thrombotic events. Catastrophic antiphospholipid syndrome (CAPS) is defined by the clinical manifestations of sudden onset of multiple organ involvements including renal failure or acute respiratory distress syndrome in patients with primary or secondary APS (6-8). CAPSis characterized by microangiopathy, that is, occlusive vascular disease affecting predominantly small vessels of different organs, particularly kidney, lung, brain, heart, and liver. Therefore, the similarities and/or differences in the clinical features and the pathogenesis must be clarified to differentiate CAPSfrom thrombotic thrombocytopenic purpura (TTP) and other related generalized non-inflammatory thrombotic diseases (9).