Comparison of plasma sOX40 (A) and sOX40L (B) from patients with early rheumatoid arthritis (eRA) (n =76), chronic rheumatoid arthritis (cRA) (n = 15), and healthy volunteers (HV) (n = 34). Plasma samples from patients with eRA were obtained at treatment initiation (0), and after 3 and 12 months of treatment. Patients with cRA had all had disease for more than 8 years. Paired data (within the eRA group) were analyzed by Wilcoxon signed-rank test, non-paired data were analyzed by Mann-Whitney U-test. Boxes represent median with interquartile range, and whiskers represent the 5th to 95th percentile: *P <0.05; **P <0.01; ***P <0.001. ELISA cutoff is indicated by the dotted line.