IL-21 is involved in the pathogenesis of EAM IL-21 is involved in the pathogenesis of EAM. EAM was induced in IL-21−/− mice and WT mice. IL-21 is involved in the pathogenesis of EAM. EAM was induced in IL-21−/− mice and WT mice. (A) Upper panel, Data are mean ± SEM of muscle weakness of EAM-induced mice. n = 5 mice. Middle panels, Representative photomicrographs of H&E staining of the section of quadriceps. Scale bars, 100 μm. Lower panel, Mean ± SEM of muscle histological scores. n = 11 (WT mice) and 8 (IL-21−/− mice). (B) Mean ± SEM of the numbers of indicated cells harvested from the muscle. n = 12 for cell populations except for SLECs. n = 5 (WT mice) and 7 (IL-21−/− mice) for SLECs. (C) The frequencies of GC B cells, Tfh cells, and Th17 cells in draining LNs at day 15. n = 5 (WT mice) and 6 (IL-21−/− mice). (D) Upper panel, Representative FACS profiles of CD4 versus IL-21 of CD45+ CD11b− lymphocytes in the muscle of indicated mice. n = 3. Lower panel, Representative FACS profiles of CXCR5 versus either PD-1, CCR2, CCR5, CCR9, or CCR6 on IL-21–producing CD4+ T cells in the draining LNs and muscle. Data are representative of four independent experiments. *p < 0.05. Takahiro Kageyama et al. ImmunoHorizons 2017;1:176-187 Copyright © 2017 The Authors