title: Detection of DNA of Chlamydophila psittaci in subjects with psoriasis: a casual or a causal link?
abstract: BACKGROUND
  Recent evidence indicates that subclinical infection by Chlamydophila psittaci occurs in a significant percentage of patients with chronic inflammatory polyarthritis, including psoriatic arthritis.
  
  
  OBJECTIVE
  To assess the prevalence of Chlamydiae infection in a large cohort of well-characterized patients with psoriasis.
  
  
  METHODS
  The presence of a subclinical C. psittaci infection was investigated in 64 patients with psoriasis, including 12 patients with psoriatic arthritis. Two hundred and twenty-five healthy controls were also investigated. The presence of infection was assessed in peripheral blood mononuclear cells using several polymerase chain reaction protocols, targeting different regions of the bacterial genome. The DNA of other species (Chlamydophila pneumoniae and Chlamydia trachomatis) was also investigated.
  
  
  RESULTS
  Chlamydophila psittaci infection was observed in a significantly higher percentage of patients with psoriasis (11/64, 17%) compared with healthy controls (1/225, 0.4%) (odds ratio 46.49, 95% confidence interval 5.87-368.03; P < 0.0001). No differences in age, sex or disease duration were noticed between positive and negative patients, but the majority of the positive patients were on immunomodulatory treatments.
  
  
  CONCLUSIONS
  Chlamydophila psittaci may be an infectious trigger possibly involved in the pathogenesis of psoriasis.
authors.affiliation: Institute of Dermatology, Department of Experimental and Clinical Medicine, DISM, University of Udine, Ospedale San Michele di Gemona, piazza Rodolone 1, 33013 Gemona del Friuli, Udine, Italy. giuseppe.stinco@uniud.it
authors.forename: G
authors.initials: G
authors.lastname: Stinco
authors.forename: M
authors.initials: M
authors.lastname: Fabris
authors.forename: E
authors.initials: E
authors.lastname: Pasini
authors.forename: E
authors.initials: E
authors.lastname: Pontarini
authors.forename: M M
authors.initials: MM
authors.lastname: Patriarca
authors.forename: F
authors.initials: F
authors.lastname: Piccirillo
authors.forename: S
authors.initials: S
authors.lastname: De Vita
authors.forename: R
authors.initials: R
authors.lastname: Dolcetti
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D002691:Chlamydophila psittaci / Q000235:genetics / Q000302:isolation & purification*; D015331:Cohort Studies; D004269:DNA, Bacterial / Q000235:genetics*; D005260:Female; D006801:Humans; D007558:Italy; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D009956:Psittacosis / Q000382:microbiology*; D011565:Psoriasis / Q000382:microbiology*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial