Continuous detection of circulating antibody-secreting cells during B-cell depletion with RTX. (A) Peripheral blood CD19⁺/CD20⁺ naïve and memory B-cell counts and CD19⁺/CD20⁻/CD27^high plasmablast and plasma cell counts in RTX-treated patients with rheumatoid arthritis (RA; open boxes). Healthy, untreated controls (HC; n = 41; gray boxes) are shown for comparison. (B) Detection of functional immunoglobulin (Ig)–secreting cells from peripheral blood of patients with RA during B-cell depletion after RTX treatment with the use of an EliSpot assay (5 samples from 4 independent experiments; open boxes; error bars indicate SD of duplicates). The gray bar depicts corresponding values obtained from 10 healthy persons (error bars indicate SD of 10 samples tested).