title: Contribution of myeloperoxidase and inducible nitric oxide synthase to pathogenesis of psoriasis.
abstract: BACKGROUND
  Histological changes of psoriasis include invasion of neutrophils into the epidermis and formation of Munro abscesses in the epidermis. Neutrophils are the predominant white blood cells in circulation when stimulated; they discharge the abundant myeloperoxidase (MPO) enzyme that uses hydrogen peroxide to oxidize chloride for killing ingested bacteria.
  
  
  OBJECTIVE
  To investigate the contribution of neutrophils to the pathogenesis of psoriasis at the blood and tissue levels through inducible nitric oxide synthase (iNOS) and MPO.
  
  
  METHODS
  A total of 50 adult patients with a chronic plaque form of psoriasis and 25 healthy controls were enrolled to this study. Serum MPO and iNOS levels were measured using ELISA method. Two biopsy specimens were taken in each patient from the center of the lesion and uninvolved skin. Immunohistochemistry was performed for MPO and iNOS on both normal and psoriasis vulgaris biopsies.
  
  
  RESULTS
  While a significant difference between serum myeloperoxidase levels were detected, a similar statistical difference between participants in the serum iNOS levels was not found. In immunohistochemistry, intensely stained leukocytes with MPO and intensely staining with iNOS in psoriatic skin was observed.
  
  
  CONCLUSIONS
  Neutrophils in psoriasis lesions are actively producing MPO and this indirectly triggers the synthesis of iNOS. Targeting of MPO or synthesis of MPO in the lesion area may contribute to development of a new treatment option.
authors.affiliation: Dermatology Department, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey.
authors.forename: Nursel
authors.initials: N
authors.lastname: Dilek
authors.affiliation: Microbiology Department, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey.
authors.forename: Aziz Ramazan
authors.initials: AR
authors.lastname: Dilek
authors.affiliation: Pathology Department, Şevket Yılmaz Education and Research Hospital, Bursa, Turkey.
authors.forename: Yakup
authors.initials: Y
authors.lastname: Taşkın
authors.affiliation: Pathology Department, Şevket Yılmaz Education and Research Hospital, Bursa, Turkey.
authors.forename: Taşkın
authors.initials: T
authors.lastname: Erkinüresin
authors.affiliation: Pathology Department, Şevket Yılmaz Education and Research Hospital, Bursa, Turkey.
authors.forename: Ömer
authors.initials: Ö
authors.lastname: Yalçın
authors.affiliation: Dermatology Department, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey.
authors.forename: Yunus
authors.initials: Y
authors.lastname: Saral
keywords: inducible nitric oxide; myeloperoxidase; psoriasis