Description
Interleukin-20 (IL-20) is a pleiotropic inflammatory protein belonging to the IL-10 family of cytokines. Members of this family share partial homology in their amino acid sequences but they are dissimilar in their biological functions. IL-20 is capable of stimulating colony formation by CD34+ multipotential progenitors but not by other progenitor cells. 1 It is produced by activated keratinocytes and monocytes and transmits an intracellular signal through two distinct cell-surface receptor complexes on keratinocytes and other epithelial cells. IL-20 regulates proliferation and differentiation of keratinocytes during inflammation, particularly inflammation associated with the skin. A specific receptor for this cytokine is expressed in skin and upregulated dramatically in psoriatic skin, suggesting a role for this protein in epidermal function and psoriasis.2 Human IL-20 is active on mouse cells