Serum interleukin-6 and survivin levels predict clinical response to etanercept treatment in patients with established rheumatoid arthritis.

OBJECTIVES

To investigate the correlation of nine potential biomarkers with clinical response to etanercept (ETN) therapy in establish rheumatoid arthritis (RA) patients.

METHODS

Seventy-three patients with established RA were enrolled in the prospective cohort study. Sixty-nine of 73 cases were included into final analysis for response after 24-week ETN therapy. Serum expression of nine studied proteins was measured by enzyme-linked immunosorbent assay (ELISA). Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-17A, IL-21, IL-34, RANKL, survivin, and COMP were selected as candidate biomarkers.

RESULTS

Serum IL-6 level was increased in responders than in nonresponders at baseline, p = .034; to the contrary, serum survivin level was decreased in responders, p = .009. Receiver operating characteristic (ROC) curve illuminated the combination of IL-6 and survivin expressions could predict clinical response with a high AUC 0.875, 95% CI: 0.771-0.976. Furthermore, we found the combination of IL-6 high expression and survivin low expression increased the responding possibility to nearly 20-fold (OR 19.687, 95% CI: 4.087-94.839, p < .001) compared to IL-6 low or survivin high expression by univariate analysis. However, only survivin low expression (p = .002) and CRP (p = .014) high expression were independent predictive factors for achieving clinical response, while IL-6 lack independent predictive value (p = .267).

CONCLUSIONS

Comprehensive measurement of IL-6 and survivin in serum could be served as a convincing biomarker for clinical response in ETN-treated patients with established RA.