IL21 and rheumatoid arthritis: The present study, which was designed to assess systematically the association between synovial ELN and cytokines potentially involved in the pathogenesis of RA, could not reproduce the association with IL-7 but identifies for the first time a robust association between synovial ELN and increased expression of IL-23 and downstream cytokines such as IL-17F, IL-21 and IL-22.