Background We previously reported that a chemokine stromal cell-derived factor 1 (SDF-1) increased in joint fluid of rheumatoid arthritis (RA) without biologics compared with osteoarthritis . However there is no investigation whether SDF-1 and its receptor CXCR4 axis associate to disease activity and bone and joint destruction.
Objectives This study aimed to analyze whether SDF-1 and CXCR4 related to the clinical outcome and bone and joint destruction in RA treated with golimumab. On aspect of assessment of large joint destruction, compared with the Larsen grade, we used the Assessment of Rheumatoid Arthritis by Scoring of Large-Joint Destruction and Healing in Radiographic Imaging (ARASHI) score has a high intraclass correlation coefficient (ICC) when assessing large joint destruction .
Methods Synovial tissues were obtained from 15 golimumab-treated patients and assessed for SDF-1 and CXCR4 with a new immunohistological scoring system (IH score) . The IH score was applied for the analysis of correlation between synovial SDF-1 or CXCR4 and DAS28 (CRP), Rooney score, synovial tumor necrosis factor alpha (TNF-α) or interleukin-6 (IL-6), CD4, CD20, CD68, vascular endothelial growth factor (VEGF) and ARASHI score. Receiver-operating characteristic (ROC) analysis was performed to predict ARASHI score by using IH scores of CXCR4.
Results The IH score of SDF-1 strongly correlated with the disease activity score DAS28 (CRP) and serum IL-6. The IH score of CXCR4 significantly correlated with the synovial CD4 and ARASHI score. IH score of VEGF was significantly correlated serum IL-6. ROC analysis of CXCR4 and ARASHI score (>10 points) revealed cutoff of IH score at 12 points (sensitivity 0.875, specificity 0.429, Odds 5.25) for predicting joint destruction during treatment.
Conclusions This study indicates that the synovial SDF-1 correlated with the disease activity and its receptor CXCR4 related to joint destruction in patients with rheumatoid arthritis treated with golimumab.
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Acknowledgements This work was supported in part by Grant-in-Aid for Scientific Research (KAKENHI) (C) (24592284) from the Ministry of Education, Culture, Sports, Science and Technology and the Japan Society for the Promotion of Science.
Disclosure of Interest None declared