Patients with anticardiolipin antibodies with and without antiphospholipid syndrome: their clinical features and beta 2-glycoprotein-I plasma levels.

The clinical and serological features of 38 aCL-positive patients were compared to those of 45 aCL-negative patients. A significantly higher incidence of thrombophlebitis and livedo reticularis was found in aCL-positive patients. There were 13 aCL positive patients with thrombophlebitis and/or arterial thromboses and these 13 patients were designated as having the antiphospholipid syndrome (APS) while the remaining 70 patients were diagnosed as having Systemic Lupus Erythematosus (SLE). APS patients also had a high incidence of arterial occlusions, recurrent abortions and strokes compared to SLE patients. Patients with high levels of IgG-aCL were more likely to have APS, while patients with low levels of IgG-aCL or IgM-aCL only were more likely to have SLE without the clinical features of APS. Since aCL antibodies have recently been shown to interact with a phospholipid-binding plasma protein beta 2-glycoprotein-I (beta 2-GPI), we measured the beta 2-GPI levels in these patients and found that beta 2-GPI levels are significantly higher in APS compared to SLE patients negative for aCL antibodies. Since beta 2-GPI is known to exert multiple effects on coagulation processes the interaction of aCL antibodies with this glycoprotein may play a pathogenic role in APS.