Highly sensitive B cell analysis predicts response to rituximab therapy in rheumatoid arthritis

Objective In rheumatoid arthritis (RA), B cell depletion occurs in all patients treated with rituximab, but the clinical responses to rituximab are variable. A highly sensitive assay was used to test the hypothesis that B cell depletion is variable, and that incomplete depletion leads to a poorer outcome. Methods Sixty patients with active RA unresponsive to anti–tumor necrosis factor agents received two 1‐gram infusions of rituximab. B cell...