Clinical significance of anticardiolipin and anti-β2-glycoprotein I antibodies

Background: Anticardiolipin (aCl) and anti-beta(2)-glycoprotein I (anti-beta(2)-gpI) antibodies are autoantibodies associated with the antiphospholipid syndrome (APS), which is characterized by both arterial and venous thrombosis and miscarriages. The scope of this study was to explore the clinical characteristics of patients with aCl and anti-beta(2)-gpI antibodies. Methods: ACl were tested in 3,600 consecutive sera in our laboratory between January 1999 and June 2001. The clinical diagnosis and prevalence of thrombosis and pregnancy morbidity were retrospectively reviewed in aCl-positive patients. Furthermore, the frequency of anti-beta(2)-gpI antibodies, lupus anticoagulant (LA), prolonged activated partial thromboplastin time (aPTT), and thrombocytopenia were investigated in aCl-positive patients. Results: 147 aCl-positive patients, 110 women and 37 men with a mean age of 41 years (range 7.8-82.5), were identified. 42 (28.6%) aCl-positive patients fulfilled the criteria for APS which was secondary to a connective tissue disorder in 8 patients. The frequency of anti-beta(2)-gpI antibodies and LA, prolonged aPTT, and thrombocytopenia in aCl-positive patients was 23.8, 27.2, 25.7 and 9.2%, respectively. The presence of both aCl and anti-beta(2)-gpI antibodies was strongly associated with clinical symptoms of APS (p=0.007) compared to p=0.008 for LA. Conclusion: Our data suggest that assessment of anti-beta(2)-gpI antibodies in addition to aCl is a valuable diagnostic tool in the workup of patients with APS. Copyright (C) 2004 S. Karger AG, Basel.