LAUSR

Introduction Clusterin (apolipoprotein J) is a molecular chaperone involved in a number of biological processes, such as inflammation and apoptosis. Recent data suggest its role in the development of autoimmune diseases and bone erosions. Objectives The aim of this study was to analyse the serum levels of clusterin in patients with early rheumatoid arthritis (RA) and in healthy controls, and to investigate the association of clusterin with disease activity and treatment response. Methods Clusterin serum levels were measured by ELISA (BioVendor) in 56 patients with early RA before and three months after treatment initiation, and in 56 age-/sex-matched healthy individuals. Disease activity was assessed by 28-joint Disease Activity Score (DAS28), Simplified Disease Activity Index (SDAI) and Clinical Disease Activity Index (CDAI). Treatment response was calculated based on the SDAI/CDAI definition. Receiver operating characteristic (ROC) curve analysis was performed to predict disease activity and treatment response after six months of therapy. Data are presented as mean ±SD. Results Concentrations of clusterin at baseline were significantly higher in patients with early RA compared with healthy controls (75.1±12.4 vs 56.7±9.7, p<0.001). After three months of therapy, clusterin levels decreased and were comparable to those in healthy subjects (57.7±9.7 vs 56.7±9.7, p>0.05). Although clusterin levels did not correlate with disease activity at baseline, they positively correlated with CDAI and SDAI at month 3 (r=0.294, p=0.030 and r=0.269, p=0.047, respectively) and at month 6 after treatment initiation (r=0.318, p=0.021 and r=0.339, p=0.013, respectively). Using ROC analysis, clusterin baseline levels predicted moderate to high disease activity according to CDAI (AUC=0.829 (95% CI: 0.721 to 0.937), p<0.001) and SDAI (AUC=0.709 (95% CI: 0.548 to 0.869), p=0.019), and major treatment response after 6 months of therapy (AUC=0.696 (95% CI: 0.549 to 0.842), p=0.015 for both). Conclusions We demonstrate here for the first time increased clusterin levels in patients with early rheumatoid arthritis and propose clusterin as a predictive biomarker for assessing disease activity and treatment response. Acknowledgements Supported by the project of MHCR for conceptual development of research organisation 00023728, research project SVV 260 373 and project GAUK No. 5 34 217. Disclosure of interest None declared