TY - JOUR T1 - Inhibition of annexin V binding to cardiolipin and thrombin generation in an unselected population with venous thrombosis. JF - The Journal of Rheumatology JO - J Rheumatol SP - 1990 LP - 1993 VL - 30 IS - 9 AU - John G Hanly AU - Stephanie A Smith AU - David Anderson Y1 - 2003/09/01 UR - http://www.jrheum.org/content/30/9/1990.abstract N2 - OBJECTIVE: To examine the effect on annexin V binding to cardiolipin (CL) and in vitro thrombin generation by plasma samples from an unselected population of patients with confirmed venous thrombosis and matched controls. The prevalence of autoimmune antiphospholipid antibodies (aPL) was also determined. METHODS: A total of 111 patients who presented to a single emergency room with symptoms suggestive of venous thromboembolic (VTE) disease were studied. In 34 patients the diagnosis of lower limb deep venous thrombosis (DVT) and/or pulmonary embolus (PE) was confirmed (VTE+ group). In the remaining 77 patients the diagnostic workup was negative (VTE- group). Plasma samples were collected prior to the initiation of anticoagulation and examined for IgG anticardiolipin (aCL), IgG anti-beta2-glycoprotein I (GPI), and IgG anti-prothrombin (aPT antibodies) by ELISA. In addition, the effect of individual patient and control plasma samples on annexin V binding to CL and on in vitro thrombin generation was determined by a competitive ELISA and a chromogenic assay, respectively. RESULTS: The prevalence and levels of IgG aCL, anti-beta2-GPI, and aPT antibodies were similar in the VTE+ and VTE- groups. However, plasma samples from the VTE+ group caused a significant inhibition of in vitro thrombin generation (mean +/- SD Z score: -0.66 +/- 0.97 vs 0.26 +/- 1.46; p < 0.001) and a concurrent but less impressive inhibition of annexin V binding to CL (mean +/- SD Z score: -2.53 +/- 1.44 vs -2.05 +/- 1.61; p = 0.123). Upon analyzing a panel of clinical and laboratory variables, only age and inhibition of thrombin generation were significantly associated with VTE disease. CONCLUSION: Our findings suggest that subtle abnormalities in annexin V physiology may contribute to the procoagulant state in patients with idiopathic venous thrombosis. ER -