THU0278 Increased Platelet Aggregation by Von Willebrand Factor Activity Correlates with anti-dsDNA Antibody Levels and Acute Phase Reactants in Patients with Systemic Lupus Erythematosus

BackgroundVon Willebrand Factor (vWF) typically is released in response to endothelial damage or dysfunction to promote thrombus formation. In Systemic Lupus Erythematosus (SLE) patients vWF protein levels (vWF:Ag) predict cardiovascular events [1], but endothelial dysfunction in SLE is an incompletely understood multifactorial process [2].ObjectivesTo investigate whether vWF functional activity (VWF:RCo) is related to clinical disease activity, markers of inflammation, vascular risk factors and events in SLE.MethodsA cross sectional study in patients (n=90) that fulfilled ACR classification criteria for SLE and had detailed clinical information and serology collected at an extended outpatient visit. VWF functional activity was determined by ristocetin induced platelet aggregation (vWF:RCo), while vWF protein level was measured by turbidimetric assay (vWF:Ag). Variables included in this study were: SLEDAI2K; SLICC-DI; immunosuppressive drug usage (n=33); anticoagulant therapy (n=33); antiphospholipid antibody status (aPL) and syndrome (APS) and levels for anti-dsDNA Ab, B-cell activating factor (BAFF), IL-6 and TNFα, acute phase reactants and plasma Factor VIII [3, 4].ResultsPlatelet aggregation by vWF was significantly higher in SLE patients compared to healthy controls (n=10) (median vWF:RCo, 123% vs 78%, p=0.004) as were vWF:Ag levels (142% vs 107%, p=0.001). VWF:RCo correlated with levels of ESR (Rs 0.332, p=0.01), anti-dsDNA Ab (Rs 0.26, p=0.02), LDH (Rs 0.26, p=0.016), ceruloplasmin (Rs 0.367, p