IL-20 is a pro-inflammatory cytokine primarily secreted by monocytes and keratinocytes that plays crucial roles in immune regulation, tissue remodeling, and epithelial homeostasis 12. It enhances wound-healing and restores epithelial layer integrity during infection and inflammatory responses 1. IL-20 signals through two receptor complexes: the type I complex (IL20RA/IL20RB) and type II complex (IL22RA1/IL20RB) 34, activating JAK2/STAT3 signaling pathways 5. As an IL-10 family member, IL-20 maintains tissue epithelial integrity and homeostasis while facilitating tissue healing 6. IL-20 has significant disease relevance in inflammatory and fibrotic conditions. In inflammatory bowel disease, IL-20 controls colitis resolution by suppressing interferon/STAT2 signaling in intestinal epithelial cells, with elevated levels correlating with anti-TNF therapy response 7. In osteoporosis, IL-20 expression from mutant macrophages drives osteoclastogenesis 8. IL-20 receptor signaling aggravates pulmonary fibrosis by promoting profibrotic macrophage activation via JAK2/STAT3 and PI3K/AKT pathways 9. In dry eye disease, IL-20 is significantly upregulated in tears and induces corneal epithelial cell death via NFAT5 activation 10. These findings establish IL-20 as a therapeutic target across multiple inflammatory and fibrotic diseases.