CHEMOKINE CCL18 ENRICHED IN SYNOVIAL FLUID IS INVOLVED IN JOINT DESTRUCTION THROUGH PROMOTING MIGRATION OF FIBROBLAST-LIKE SYNOVIOCYTES IN RHEUMATOID ARTHRITIS

Career situation of first and presenting author Young investigator. Introduction CC chemokine ligand 18 (CCL18) which is either constitutively expressed or induced in monocytes/macrophages and dendritic cells has been reported to be highly expressed in peripheral blood and synovial fluid of rheumatoid arthritis (RA) patients compared with healthy controls, indicating the possible role of CCL18 in the development and pathogenesis of RA. Objectives To explore the association of serum and synovial fluid CCL18 with clinical and radiographic outcome in RA and its potential effect on RA fibroblast-like synoviocytes (FLS). Methods Consecutive patients with active RA (DAS28-CRP>2.6) were recruited. Synovial fluid was collected from inflamed joints if available. Demographic and clinical data were collected according to the 2017 EULAR recommendation. Serum and synovial fluid CCL18 was detected by ELISA. RA-FLS was cultured in vitro with RA synovial fluid and neutralizing antibody to CCL18. Migration/invasion ability was analyzed by Transwell assay. Results Among 83 RA patients, age (median and IQR, similarly hereinafter) was 50 (41∼58) years old and 65 patients (78%) were female, with median disease duration 36 (12∼102) months, median DAS28-CRP 5.0 (4.6∼6.1). Serum CCL18 was 107 (80∼126) ng/mL, which was significantly higher than healthy controls [n=25, 51 (29∼70) ng/mL, p Synovial fluid CCL18 of 31 patients was 719 (415∼1271) ng/mL, which was significantly higher than corresponding serum level (Paired test, p When incubated with RA synovial fluid, the migration ability of RA-FLS was significantly increased; but this effect was Inhibited by neutralizing antibody to CCL18. Conclusions CCL18 elevates especially in synovial fluid of RA patients, which may correlate with one-year radiographic progression through promoting migration of RA-FLS. Disclosure of Interest None declared.