Abstract
Introduction: Lupus anticoagulants(LA) are immunoglobulins which inhibit phospholipid dependent coagulation tests and associated with thromboembolic event. The autoantibodies that cause Lupus anticoagulant activity are heterogeneous but predominantly directed against β-2-glycoprotein(β2GPI) or prothrombin. The purpose of this study was to evaluate the prevalence of IgG, IgM anti-cardiolipin antibody(ACA), anti-β2GPI antibody and anti-prothrombin antibody in patient with lupus anticoagulant activity, and to predict the risk of thromboembolic event in patients with different immunologic profile.
Materials and methods: Lupus anticoagulant positive plasma samples from 163 patients which were sent us under the impression of antiphospholipid antibody syndrome were selected. The activity of LA was detected by mixing test and simplified DRVVT test (Gradipore Ltd, Sydney, Australia). IgG, IgM ACA (Inova Diagnostics, Sandiego, CA, USA), anti-β2GPI antibody and anti-prothrombin antibody (BL-Diagnosika, Gmbh, Mainz, Germany) were measured by commercial enzyme linked immunoassay (ELISA). The 163 patients divided into nine groups according to the results of ELISA for evaluation of correlation with thromobosis.
Results: A history of 1 or more thromboembolic events was found in 49 patients (30.1%): venous thrombosis in 29 patients (17.8%), arterial thrombosis in 29 patiensts (17.8%) and recurrent events in 14 patients (8.6%). The positivity of ELISA was follows; IgG ACA, 14 cases (8.6%); IgM ACA, 24 cases (14.7%); IgG and IgM ACA, 3 cases (3.7%); IgG anti-β2GPI antibody, 10 cases (6.1%); IgM anti-β2GPI antibody, 5 cases (3.1%); IgG and IgM anti-β2GPI antibody, 3 cases (1.8%); IgG anti- prothrombin antibody, 48 cases (29.4%); IgM anti-prothrombin antibody, 22 cases (13.5%); IgG and IgM anti-prothrombin antibody 10 cases (6.1%). Venous thrombosis prevalence was elevated in 6(25.0%) of 24 patients with IgM ACA and 1(20%) of 5 patients with IgM anti-β2GPI antibody. Arterial thrombosis prevalence was elevated in 3(30.0%) of 10 patients with IgG anti-β2GPI antibody and 5(22.7%) of 22 patients with IgM anti-prothrombin antibody. The univariate logistic analysis of risk factors for thrombosis indicated that of IgM ACA and IgM anti-β2GPI antibody were risk factors for venous thrombosis (Odds ratio, 2.3; 95% confidence interval 0.7–7.3, OR, 2.3; 95% CI 0.1–40.5) and IgG anti-β2GPI antibody were risk factors for arterial thrombosis and recurrent events (OR, 6.3; 95%CI 0.9–46.2, OR, 5.9; 95%CI 0.4–80.4).
Conclusion: The anti-prothrombin antibody is more frequently detected in patients with LA activity than anti-β2GPI antibody. However, anti-β2GPI antibody test is more helpful to identify LA positive patients at risk of thrombosis.
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