title: Immunolocalisation of heme oxygenase isoforms in human nasal polyps.
abstract: BACKGROUND
  Carbon monoxide is an endogenous vasodilator gas produced by the enzyme heme oxygenase (HO). HO is expressed in human nasal mucosa, but its pathophysiological role in nasal inflammatory diseases is not fully understood. The aim of this study was to detect and compare the expression of HO-1 and -2 isoforms in nasal polyps with normal nasal mucosa.
  
  
  METHODS
  Immunohistochemical analysis using antibodies specific for HO-1 and -2 was conducted on nasal polyps from nine patients with allergic nasal polyposis, and on normal nasal mucosa from six controls.
  
  
  RESULTS
  Intense HO-1 immunoreactivity was observed in nasal polyp epithelium but was absent in normal nasal mucosa. HO-2 staining was observed in respiratory epithelium, vascular endothelium and seromucous glands, with no difference observed between nasal polyps and normal nasal mucosa.
  
  
  CONCLUSIONS
  HO-1 expression is up-regulated in nasal polyp epithelium, supporting the theory that respiratory epithelium plays a role in the pathogenesis of nasal polyposis.
authors.affiliation: Department of Otorhinolaryngology, St George's Hospital Medical School, London, UK. stephenlo@lycos.co.uk
authors.forename: S
authors.initials: S
authors.lastname: Lo
authors.forename: S
authors.initials: S
authors.lastname: Di Palma
authors.forename: E
authors.initials: E
authors.lastname: George
authors.forename: A W
authors.initials: AW
authors.lastname: McCombe
mesh_terms: D002248:Carbon Monoxide / Q000032:analysis / Q000378:metabolism*; D016022:Case-Control Studies; D006419:Heme Oxygenase (Decyclizing) / Q000032:analysis / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D009297:Nasal Mucosa / Q000378:metabolism*; D009298:Nasal Polyps / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D002248:Carbon Monoxide; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; C105245:heme oxygenase-2