自己免疫疾患における組織の炎症においてTh17細胞が関与しているそうです。しかしTh17細胞は一種類というわけではなく、病態に関与しないTh17細胞もあるとのこと。また、自己免疫性の炎症を引き起こすのはTh17細胞ではなくGM-CSF産生T細胞（ThGM）だという報告もあるようです。混沌としていますね。

1. Stem-like intestinal Th17 cells give rise to pathogenic effector T cells during autoimmunity Cell 184(26):6281-6298.E23, DECEMBER 22, 2021. However, recent studies propose that IL-17 and Th17 cells are not critical for driving autoimmune tissue inflammation (Haak et al., 2009; McGinley et al., 2020), whereas granulocyte-macrophage colony-stimulating factor (GM-CSF)-producing T cells (ThGM) were proposed as the primary inducers of autoimmune tissue inflammation (Komuczki et al., 2019; Rasouli et al., 2020; Codarri et al., 2011; Galli et al., 2019).
2. Single-Cell Genomics Unveils Critical Regulators of Th17 Cell Pathogenicity CELL 163(6):1400-1412, DECEMBER 03, 2015
3. CD5L/AIM Regulates Lipid Biosynthesis and Restrains Th17 Cell Pathogenicity. Cell 163(6):1413-1427, DECEMBER 03, 2015. IL-17-producing Th17 cells are present at tissue inflammation sites and contribute to the pathogenesis of human autoimmune diseases and relevant murine models (Kleinewietfeld and Hafler, 2013, Lee et al., 2014). However, not all Th17 cells induce tissue inflammation and disease (i.e., are “pathogenic”).