TBX21 and rheumatoid arthritis: To validate the gating strategy for the other CCR6+ subpopulations we sorted Th1, Th17, Th17.1 and CCR4/CXCR3 DP CCR6+ Th cells from patients with RA and analyzed their Th17 and Th1 profile by the transcription levels of IL-17A, IFN-γ, RORC and TBX21.