Interleukin-20 (IL-20) is a member of the IL-10 cytokine family that plays a role in regulating inflammatory and immune responses. In humans, IL-20 is produced by activated monocytes, keratinocytes, and other cell types in response to pro-inflammatory stimuli. IL-20 signals through a receptor complex composed of IL-20R1 and IL-20R2 subunits, leading to the activation of downstream signaling pathways, including the JAK-STAT pathway. IL-20 has been implicated in various inflammatory conditions, including psoriasis, rheumatoid arthritis, and inflammatory bowel disease. It exerts its biological effects by promoting the production of pro-inflammatory cytokines, chemokines, and matrix metalloproteinases, contributing to tissue inflammation and remodeling.