ABSTRACT
BACKGROUND: The presence of lupus anticoagulants (LA) is a strong risk factor for thrombosis in antiphospholipid syndrome. We investigated the usefulness of addition of silica clotting time (SCT) to the pre-existing dilute Russell's viper venom test (dRVVT) for detection of LA. Also, we analyzed differences in the thrombotic features and the characteristics of antiphospholipid antibodies between dRVVT and SCT. METHODS: A total of 167 patients positive for LA or anti-cardiolipin (anti-CL) antibody and 76 healthy controls were enrolled. The dRVVT and SCT were used for detection of LA. Anti-CL, anti-beta2-glycoprotein I (anti-beta2 GPI) and anti-prothrombin (anti-PT) antibodies were measured using commercial ELISA kits. RESULTS: In detection of thrombosis, the sensitivity of the combined test of SCT and dRVVT was 56.4%, which was higher than that of dRVVT alone (46.2%) or SCT alone (23.1%). The specificity of the combined test (80.9%) was comparable to that of dRVVT (81.9%). Also, odds ratio for predicting thrombosis was higher in the combined test than in dRVVT or SCT alone. When normalized LA ratio of the two tests was compared, the group of patients with higher ratio of SCT showed significantly higher prevalence of recurrent abortion and higher positivity of IgG types of anti-CL, anti-beta2 GPI and anti-PT than the group with higher ratio of dRVVT. CONCLUSIONS: Addition of SCT to dRVVT can improve the detection sensitivity of thrombosis in LA test. And the high normalized LA ratio of SCT may be a useful parameter for detection of recurrent abortion.
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Antibodies, Anticardiolipin/analysis , Antibodies, Antiphospholipid/analysis , Blood Coagulation Tests/methods , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Lupus Coagulation Inhibitor/blood , Prothrombin/immunology , Prothrombin Time/methods , Reagent Kits, Diagnostic , Sensitivity and Specificity , Silicon Dioxide/chemistry , Thrombosis/diagnosis , beta 2-Glycoprotein I/immunologyABSTRACT
To develop an assay for the measurement of this anti-human beta2-glycoprotein I [a beta2-GPI] This study was conducted from September 2004 to December 2006. The patients attending the Rheumatology Clinic were chosen from several centers in the Eastern region of Saudi Arabia because they had complications. An enzyme-linked immunosorbent [ELISA] assay was optimized and developed to measure IgG a beta2-GPI antibody levels in humans. Fifty normal blood donors arid 50 systemic lupus erythrematosis [SLE] patients were selected for this experiment. Raised IgG a beta2-GPI antibody levels were found in 80% of SLE patients. Interestingly, raised IgG a beta2-GPI antibody levels were associated with the presence of venous thrombosis and thrombocytopenia. The real value of IgG a beta2-GPI as a predictor for the future clinical complications needs to be confirmed in prospective controlled studies investigating clinical complications in relationship to IgG a beta2-GPI and to other risk factors for thrombosis