title: Interleukin 20 protein locates to distinct mononuclear cells in psoriatic skin.
abstract: We previously demonstrated that mRNA for the pro-inflammatory cytokine interleukin 20 (IL-20) is expressed in suprapapillary keratinocytes of lesional psoriatic skin (LS). Here, we describe the distribution of IL-20 protein and the identity of the IL-20-positive cells in LS. We found that the main part of IL-20 immunoreactivity is present in mononuclear cells of the dermal papillae, and that the IL-20-positive cells located in the papillae were langerin+, CD1a+, CD4+ and CD303+. These cells might be immature dendritic cell. In situ hybridization for IL-20 mRNA on non-LS, ex vivo stimulated with IL-1β revealed a colocalization between IL-20 mRNA and the keratinocyte marker CK14. No IL-20 mRNA was detected in the dermal mononuclear cells. Our results suggest that IL-20 is produced by keratinocytes, released into the epidermis and then possibly taken up by papillary mononuclear cells. Our study supports that IL-20 is involved in the pathogenesis of psoriasis.
authors.affiliation: Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark; Department of Biomedicine, Aarhus University, Aarhus, Denmark.
authors.forename: Rikke
authors.initials: R
authors.lastname: Bech
authors.forename: Kristian
authors.initials: K
authors.lastname: Otkjaer
authors.forename: Svend
authors.initials: S
authors.lastname: Birkelund
authors.forename: Thomas
authors.initials: T
authors.lastname: Vorup-Jensen
authors.forename: Ralf
authors.initials: R
authors.lastname: Agger
authors.forename: Claus
authors.initials: C
authors.lastname: Johansen
authors.forename: Lars
authors.initials: L
authors.lastname: Iversen
authors.forename: Knud
authors.initials: K
authors.lastname: Kragballe
authors.forename: John
authors.initials: J
authors.lastname: Rømer
mesh_terms: D015703:Antigens, CD / Q000378:metabolism; D018949:Antigens, CD1 / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004817:Epidermis / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism*; D053547:Keratin-14 / Q000378:metabolism; D015603:Keratinocytes / Q000378:metabolism; D037181:Lectins, C-Type / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000378:metabolism*; D037241:Mannose-Binding Lectins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D011565:Psoriasis / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism; D012867:Skin / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; C419393:CD1a antigen; C121916:CD207 protein, human; D015704:CD4 Antigens; C443299:CLEC4C protein, human; D053583:Interleukin-1beta; D007378:Interleukins; D053547:Keratin-14; D037181:Lectins, C-Type; D037241:Mannose-Binding Lectins; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; C422042:interleukin 20
keywords: IL-20; immature dendritic cells; langerin; psoriasis; suprapapillary keratinocytes