Baseline immunostaining for selected synovial markers of response to adalimumab therapy. Synovial samples of rheumatoid arthritis patients who responded or who did not respond to adalimumab therapy were stained at baseline with polyclonal antibodies directed at MKI67, interleukin-7 receptor α chain (IL-7R), interleukin-18 receptor accessory (IL-18rap), IL-18, and chemokine (C-X-C motif) ligand 11 (CXCL11). (a) Characteristic images of the stained markers are shown in responders (n = 20) versus non-responders (n = 5) (original magnification × 400). (b) Ratio of surface staining to staining of the nuclei (S/N). Slides were analyzed using ImageJ with six digitalized pictures (magnification × 400) obtained for each sample. Results are the mean and standard error of the mean of S/N ratio. *P < 0.05, **P < 0.005, ***P < 0.0005 using Wilcoxon matched-pairs signed rank tests.