TGFB1 and rheumatoid arthritis: Taken together, our findings demonstrate that in a chronic inflammatory environment such as RA, CXCL13‐producing CD4+ T cells that lack Tfh cell‐like features differentiate via TGF‐β signaling, but not via FoxP3, and exert their function, that is, CXCL13 production, especially in inflammatory conditions.