IL-22

IL-22 is a member of the IL-10 cytokine family that primarily mediates communication between immune cells and epithelial tissues^[1][2]. Produced by multiple leukocyte subsets, including Th17, Th22, γδ T cells, and innate lymphoid cells, IL-22 signals through a heterodimeric receptor complex expressed mainly on non-hematopoietic cells^[2][3][4]. Mechanistically, IL-22 activates the STAT3 pathway in epithelial cells, promoting anti-apoptotic, pro-proliferative, and tissue-regenerative responses^[1][3]. In the gastrointestinal tract, IL-22 enhances epithelial barrier function by stimulating mucus secretion, antimicrobial peptide production, and epithelial cell proliferation, which contributes to protection against infections and supports tissue repair^[5][6][7]. Compared with IL-17, IL-22 exerts more regenerative and protective effects rather than pro-inflammatory responses in epithelial tissues^[8]. Dysregulation of IL-22 has been implicated in autoimmune diseases, such as rheumatoid arthritis, multiple sclerosis, and inflammatory bowel disease, where aberrant signaling can exacerbate tissue pathology^[9][6]. In experimental models, IL-22 administration promotes tissue repair in lung injury, pancreatitis, and liver damage, while receptor-specific antagonists allow precise modulation of IL-22-driven responses^[1][10][11]. Therapeutic strategies targeting IL-22, including recombinant cytokines and IL-22 binding protein modulation, are being explored for chronic inflammatory disorders and gastrointestinal acute graft-versus-host disease^[12][13][11].