title: Perforin expression is upregulated in the epidermis of psoriatic lesions.
abstract: BACKGROUND
  There are currently very few data regarding the role of cell-mediated cytotoxicity in psoriasis. Both cytotoxic T lymphocytes and natural killer (NK) cells mediate cytotoxicity reactions, mainly by two distinct pathways, the perforin/granzyme and the Fas/Fas ligand pathway.
  
  
  OBJECTIVE
  To study the expression and distribution of perforin, T- and NK-cell subsets in psoriatic lesional and nonlesional skin.
  
  
  METHODS
  Skin biopsy specimens from both lesional and nonlesional skin of 11 patients with chronic plaque psoriasis and eight healthy controls were analysed by immunohistochemistry.
  
  
  RESULTS
  We found a significant increase in CD4+ and CD8+ cells in psoriatic lesions compared with nonlesional and healthy skin. The expression of CD16+ NK cells was significantly lower in lesions compared with healthy skin. Perforin expression was significantly enhanced in the epidermis of psoriatic lesions.
  
  
  CONCLUSIONS
  Perforin expression is upregulated in the epidermis of psoriatic lesions, suggesting a potential role for perforin in the creation of the psoriatic plaque.
authors.affiliation: Department of Pathology, Medical Faculty, University Rijeka, Kresimirova 42, HR-51000 Rijeka, Croatia. marijakastelan@yahoo.com
authors.forename: M
authors.initials: M
authors.lastname: Kastelan
authors.forename: L
authors.initials: L
authors.lastname: Prpić Massari
authors.forename: F
authors.initials: F
authors.lastname: Gruber
authors.forename: G
authors.initials: G
authors.lastname: Zamolo
authors.forename: G
authors.initials: G
authors.lastname: Zauhar
authors.forename: M
authors.initials: M
authors.lastname: Coklo
authors.forename: D
authors.initials: D
authors.lastname: Rukavina
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D004817:Epidermis / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007694:Killer Cells, Natural / Q000276:immunology; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008875:Middle Aged; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D011565:Psoriasis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D012867:Skin / Q000276:immunology / Q000378:metabolism; D016176:T-Lymphocyte Subsets / Q000276:immunology; D015854:Up-Regulation
chemical_list: D008562:Membrane Glycoproteins; D052899:Pore Forming Cytotoxic Proteins; D054353:Perforin