title: The role of cyclooxygenase-2 and prostaglandin E2 in the pathogenesis of cutaneous lichen planus.
abstract: BACKGROUND
  Lichen planus (LP) is an inflammatory disease of the skin and mucous membranes. Autoimmunity has been suggested as a possible cause of this disease. The cyclooxygenase enzymes (COX-1, COX-2) are the key enzymes in the conversion of arachidonic acid into prostaglandins. Prostaglandin E2 (PGE2), a key product of COX-2, has an immunomodulatory role.
  
  
  OBJECTIVE
  To map levels of COX-2 and PGE2 in cutaneous LP lesions and evaluate their role in the pathogenesis of the disease.
  
  
  METHODS
  In total, 31 patients with classic cutaneous LP and 30 age- and sex-matched healthy controls were enrolled. Skin biopsies were taken from the lesional and nonlesional skin of patients, and from the normal skin of controls. COX-2 mRNA expression was detected by real-time reverse transcription quantitative PCR, and PGE2 was detected by ELISA in skin biopsies from patients and controls.
  
  
  RESULTS
  Our analysis revealed a significantly higher expression of COX-2 mRNA and PGE2 in the LP skin biopsies compared with the control biopsies (P < 0.001 and P < 0.001, respectively). Lesional biopsies showed significantly higher expression of COX-2 mRNA and PGE2 compared with nonlesional biopsies. The levels of COX-2 and PGE2 were not found to be correlated with age, sex or disease duration.
  
  
  CONCLUSIONS
  COX-2 and its product PGE2 are strongly expressed in LP skin lesions, indicating that they have a role in the pathogenesis of LP through their immunomodulatory effects.
authors.affiliation: Dermatology Department, Faculty of Medicine, Beni Suef University, Beni Suef, Egypt.
authors.forename: A A
authors.initials: AA
authors.lastname: El-Rifaie
authors.affiliation: Biochemistry Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: L A
authors.initials: LA
authors.lastname: Rashed
authors.affiliation: Dermatology Department, Faculty of Medicine, Beni Suef University, Beni Suef, Egypt.
authors.forename: R W
authors.initials: RW
authors.lastname: Doss
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism*; D005260:Female; D006801:Humans; D008010:Lichen Planus / Q000209:etiology / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D012867:Skin / Q000378:metabolism; D055815:Young Adult
chemical_list: D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D015232:Dinoprostone