title: Characterization of the interleukin-17 isoforms and receptors in lesional psoriatic skin.
abstract: BACKGROUND
  Th17 cells are a lineage of proinflammatory T helper cells producing interleukin (IL)-17. The importance of Th17 cells in inflammation and autoimmunity has now been recognized. The IL-17 cytokine family consists of six isoforms (IL-17A-IL-17F) whereas five members of the IL-17 receptor (IL-17R) family have been identified (IL-17RA-IL-17RE).
  
  
  OBJECTIVE
  To characterize the expression of the IL-17 isoforms and receptors in lesional and nonlesional psoriatic skin. Methods Keratome and punch biopsies taken from patients with psoriasis were examined by enzyme-linked immunosorbent assay and quantitative reverse transcription-polymerase chain reaction in order to measure the IL-17 isoforms and receptors.
  
  
  RESULTS
  We demonstrated significantly increased mRNA expression of IL-17A, IL-17C and IL-17F in psoriatic skin. In contrast, the mRNA expression of IL-17B and IL-17D was significantly decreased in lesional compared with nonlesional skin, while IL-17E mRNA was undetectable. The increased mRNA expression of IL-17A, IL-17C and IL-17F was paralleled by an increased protein accumulation of these cytokines in psoriatic skin. Analysis of the IL-17R mRNA expression revealed significantly impaired mRNA expression of IL-17RB, IL-17RC, IL-17RD and IL-17RE in lesional psoriatic skin, whereas the mRNA expression of IL-17RA was similar in lesional and nonlesional psoriatic skin.
  
  
  CONCLUSIONS
  This study characterizes the mRNA profile of the IL-17 isoforms and receptors in psoriatic skin lesions. Furthermore, we demonstrate for the first time augmented protein levels of IL-17A, IL-17C and IL-17F in psoriatic skin lesions, indicating a possible role for IL-17C in addition to IL-17A and IL-17F in the pathogenesis of psoriasis.
authors.affiliation: Department of Dermatology, Aarhus University Hospital, DK-8000 Aarhus C, Denmark. claus.johansen@ki.au.dk
authors.forename: C
authors.initials: C
authors.lastname: Johansen
authors.forename: P A
authors.initials: PA
authors.lastname: Usher
authors.forename: R B
authors.initials: RB
authors.lastname: Kjellerup
authors.forename: D
authors.initials: D
authors.lastname: Lundsgaard
authors.forename: L
authors.initials: L
authors.lastname: Iversen
authors.forename: K
authors.initials: K
authors.lastname: Kragballe
mesh_terms: D002478:Cells, Cultured; D015870:Gene Expression; D006801:Humans; D020381:Interleukin-17 / Q000235:genetics / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics; D011565:Psoriasis / Q000235:genetics / Q000473:pathology*; D012333:RNA, Messenger / Q000378:metabolism*; D053722:Receptors, Interleukin-17 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic
chemical_list: D020381:Interleukin-17; D020033:Protein Isoforms; D012333:RNA, Messenger; D053722:Receptors, Interleukin-17