Changes in plasma IL-6, plasma VEGF and serum YKL-40 during Treatment with Etanercept and Methotrexate or Etanercept alone in Patients with Active Rheumatoid Arthritis Despite Methotrexate Therapy

Abstract

Changes in plasma IL-6, plasma VEGF and serum YKL-40 were determined in rheumatoid arthritis (RA) patients during treatment with etanercept alone or in combination with methotrexate. Twenty-five patients with active RA (DAS28 >/= 3.2) were randomized to receive etanercept (25 mg sc. biweekly) plus methotrexate (n = 12) or etanercept alone (n = 13). Plasma IL-6, plasma VEGF and serum YKL-40 were determined by ELISA. The 3 biomarkers and DAS28 scores were evaluated at baseline and after 4, 8, 12 and 16 weeks of treatment. At inclusion all patients had significantly (p < 0.001) elevated plasma IL-6, plasma VEGF and serum YKL-40 compared to healthy subjects. Eighteen patients responded to treatment (pooled data from both treatment groups), and they had significant (p < 0.05 to p < 0.001) decreases in plasma IL-6, plasma VEGF, serum YKL-40, ESR and DAS28 after 4 weeks of treatment and throughout the study (except serum YKL-40 at week 16). Plasma IL-6 showed the largest reductions. Non-responders had unchanged biomarkers. At week 16 the patients with DAS28 < 3.2 had lower levels compared to baseline values in plasma IL-6 (p = 0.005), plasma VEGF (p = 0.014), and ESR (p = 0.024).Plasma IL-6, plasma VEGF and serum YKL-40, which reflect different aspects of the inflammatory process, may provide useful information regarding early differentiation of responders from non-responders.

Keywords: IL-6; VEGF; YKL-40; biomarkers; etanercept; rheumatoid arthritis.

Figure 1

The changes in plasma IL-6, plasma VEGF, serum YKL-40, ESR and DAS28(ESR) in 25 RA patients during the 16-week study period, divided by being EULAR good/moderate responders or EULAR non-responders. Values are given as box and whiskers plots. Boxes indicate 25th, 50th, 75th centiles. Whiskers indicate 5th–95th percentiles. The y-axis is logarithmic for the biomarkers. *, ** and *** indicate statistically significant changes from baseline (Wilcoxon-Pratt): *p < 0.05, **p < 0.01, ***p < 0.001.