Proportion of CD27+memory B cells predicts response to tumor necrosis factor inhibitor therapy. (A) Patients with response (R) or no response (NR) (according to European League Against Rheumatism (EULAR) criteria) to tumor necrosis factor inhibitor (TNFi) at baseline (M0) (P = 0.01). The gray line indicates 26% of memory B cells, the best threshold at which to separate responders and nonresponders. (B) Levels of CD27+ B cells at baseline correlated with change in Disease Activity Score in 28 joints (DeltaDAS28) during the first 3 months of TNFi treatment (P = 0.05). Each data point represents one participant. Horizontal bars are medians, and whiskers are IQR (25th to 75th percentile).