title: Catechol-O-methyltransferase activity in psoriasis patients treated with psoralen plus ultraviolet A therapy.
abstract: BACKGROUND
  Catechol-O-methyltransferase (COMT) activity is increased in patients with mild/moderate psoriasis. Narrowband ultraviolet B (nbUVB) phototherapy decreases COMT activity. However, the effect of psoralen plus ultraviolet A (PUVA) on this enzyme activity is unknown, and it remains to be clarified if the nbUVB-induced effect in COMT activity is related to clinical response. The aim of this study is to evaluate COMT activity in moderate/severe psoriasis and assess whether PUVA therapy modifies this activity.
  
  
  METHODS
  An observational study was conducted on 18 patients with moderate/severe psoriasis and 13 matched controls. Patients were treated with PUVA twice weekly during 6 weeks, and they were evaluated for Psoriasis Area and Severity Index (PASI) and COMT activity before photochemotherapy, at the end of it and 4 weeks after stopping.
  
  
  RESULTS
  Before PUVA therapy, S(soluble)-COMT activity was significantly (P < 0.05) higher in psoriasis patients than in controls. After photochemotherapy, no significant differences were found in S-COMT activity at all end points. Photochemotherapy significantly decreased PASI but COMT activity values remained higher than those of control population.
  
  
  CONCLUSIONS
  Psoriasis patients with moderate/severe disease present higher S-COMT activity than controls. Although a good clinical response was observed, PUVA therapy does not change S-COMT activity. This differential COMT effect of PUVA and nbUVB suggests a wavelength-specific regulation.
authors.affiliation: Department of Pharmacology and Therapeutics, Faculty of Medicine, University of Porto, Porto, Portugal. mimed07127@med.up.pt
authors.forename: Pedro
authors.initials: P
authors.lastname: Souteiro
authors.forename: Maria Augusta
authors.initials: MA
authors.lastname: Vieira-Coelho
authors.forename: Maria Paula
authors.initials: MP
authors.lastname: Serrão
authors.forename: Sofia
authors.initials: S
authors.lastname: Magina
mesh_terms: D000328:Adult; D000368:Aged; D002394:Catechol O-Methyltransferase / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011701:PUVA Therapy; D011565:Psoriasis / Q000188:drug therapy* / Q000201:enzymology* / Q000473:pathology
chemical_list: D002394:Catechol O-Methyltransferase
keywords: COMT; PUVA; phototherapy; psoriasis