Circulating plasmablasts and plasma cells during B-cell depletion express IgA and receptors for mucosal homing. Representative cytometric detection of IgA (A), CCR10 (B), and β₇ integrin (C) on plasmablasts and plasma cells during RTX treatment are shown. Frequencies of IgA⁺, CCR10⁺, and β₇ integrin⁺ cells were determined in 44 healthy controls (HCs; gray boxes) and in RTX-treated patients with RA throughout therapy (open boxes). Box plots depict minimum, maximum, and median values and upper and lower quartiles.