Tumor necrosis factor‐alpha stimulated gene‐6: A biomarker reflecting disease activity in rheumatoid arthritis

BACKGROUND: To explore the serum tumor necrosis factor‐alpha stimulated gene‐6 (TSG‐6) level and its association with disease activity in rheumatoid arthritis (RA) patients. METHODS: We recruited 176 RA patients, 178 non‐RA patients (lupus erythematosus, osteoarthritis, ulcerative colitis, ankylosing spondylitis and psoriasis) and 71 healthy subjects. Serum TSG‐6 levels were detected by enzyme‐linked immunosorbent assay (ELISA). RA patients were divided into inactive RA and active RA groups by disease activity score of 28 joints based on C‐reactive protein (DAS28‐CRP). The receiver operating characteristic (ROC) curve and Spearman's rank correlation test analyzed the correlation between TSG‐6 concentration and RA disease activity. RESULTS: Tumor necrosis factor‐alpha stimulated gene‐6 levels in the RA group were increased (p < 0.01). TSG‐6 concentrations indicated an upward tendency with increased disease activity; The area under the curve (AUC) of TSG‐6 for diagnosing RA and assessing the severity of RA were 0.78 and 0.80, respectively; The combination of TSG‐6 and anti‐mutated citrullinated vimentin antibodies (anti‐MCV) (sensitivity:98.4%)improved the diagnostic accuracy of RA. Binary logistic regression analysis showed that TSG‐6 was an independent risk factor related to the severity of RA, and OR (95% CI) was 1.2 (1.003–1.453). CONCLUSION: The TSG‐6 levels in RA patients were elevated and related to disease activity. Therefore, TSG‐6 may serve as a new potential biomarker for evaluating RA disease activity.