Stem-like T cells are associated with the pathogenesis of ulcerative colitis in humans

To understand the role of T cells in the pathogenesis of ulcerative colitis (UC), we analyzed colonic T cells isolated from patients with UC and controls. Here we identified colonic CD4 + and CD8 + T lymphocyte subsets with gene expression profiles resembling stem-like progenitors, previously reported in several mouse models of autoimmune disease. Stem-like T cells were increased in inflamed areas compared to non-inflamed regions from the same patients. Furthermore, TCR sequence analysis indicated stem-like T cells were clonally related to proinflammatory T cells, suggesting their involvement in sustaining effectors that drive inflammation. Using an adoptive transfer colitis model in mice, we demonstrated that CD4 + T cells deficient in either BCL-6 or TCF1, transcription factors that promote T cell stemness, had decreased colon T cells and diminished pathogenicity. Our results establish a strong association between stem-like T cell populations and UC pathogenesis, highlighting the potential of targeting this population to improve clinical outcomes. Li et al. identify a human TCF1-expressing stem-like T cell population that is associated with immune-mediated pathogenesis in ulcerative colitis.