Plasma levels of CXCL13 in early RA patients and healthy volunteers. Levels of CXCL13 in plasma from early-stage RA patients (n = 76) and healthy volunteers (n = 38). Plasma CXCL13 levels were measured at treatment initiation (0) and after 6 months of treatment (6). Bars represent median with interquartile range. The cutoff level for detection was 7.8 pg/ml (dotted line). All values below the cutoff were assigned the cutoff value. Level of significance is indicated by asterisks (***: P <0.0001). CXCR13: C-X-C chemokine receptor type 13; RA: rheumatoid arthritis.