title: Serological and DNA-based evaluation of Chlamydia pneumoniae infection in inflammatory bowel disease.
abstract: OBJECTIVE
  Chlamydia has been associated with autoimmune diseases, but a link between chlamydial infection and the aetiopathogenesis of inflammatory bowel disease (IBD) remains controversial. In this study we assessed the relationship between chlamydial infection and IBD, as evidenced by serological measurement and DNA analysis of mucosal biopsy specimens.
  
  
  METHODS
  The sera of 78 patients with Crohn's disease (CD), 24 patients with ulcerative colitis (UC), 73 healthy family members, and 20 healthy controls were tested for anti-C. pneumoniae IgG titres. A subgroup consisting of 13 UC and 39 CD patients was screened for the presence of chlamydial DNA on 42 inflamed versus 30 non-inflamed biopsy specimens and for mutations of their NOD2/CARD15 gene.
  
  
  RESULTS
  Anti-C. pneumoniae IgG antibodies were found in the sera of 32 (41%) patients with CD, 11 (46%) patients with UC, 35 (48%) of unaffected family members, and nine (45%) unrelated healthy controls. Thirty-five percent of the control, 18% CD and 24% UC biopsy specimens contained C. pneumoniae DNA. In CD, however, C. pneumoniae DNA was significantly more frequently found in inflamed (27%) versus non-inflamed (8%) biopsy specimens (P < 0.05, Fisher's exact test). The frequencies of NOD2/CARD15 mutations were 33% for CD patients with C. pneumoniae DNA compared to 47% for CD patients without C. pneumoniae DNA.
  
  
  CONCLUSIONS
  We found no marked differences in respect to anti-C. pneumoniae serum IgG or C. pneumoniae DNA between healthy controls and patients with IBD. However, in CD patients, inflamed tissue specimens contained significantly more likely C. pneumoniae DNA compared with biopsies from unaffected areas. Thus C. pneumoniae is unlikely to be of pathogenic importance in IBD while it may still influence local clinical manifestations.
authors.affiliation: Division of Gastroenterology of the Inselspital and Department of Clinical Research, University of Bern, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Müller
authors.forename: Stephan
authors.initials: S
authors.lastname: Arni
authors.forename: Lajos
authors.initials: L
authors.lastname: Varga
authors.forename: Bruno
authors.initials: B
authors.lastname: Balsiger
authors.forename: Martin
authors.initials: M
authors.lastname: Hersberger
authors.forename: Friedrich
authors.initials: F
authors.lastname: Maly
authors.forename: Frank
authors.initials: F
authors.lastname: Seibold
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000907:Antibodies, Bacterial / Q000097:blood*; D016022:Case-Control Studies; D023521:Chlamydophila Infections / Q000150:complications*; D016993:Chlamydophila pneumoniae / Q000276:immunology / Q000302:isolation & purification*; D003093:Colitis, Ulcerative / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D003424:Crohn Disease / Q000235:genetics / Q000378:metabolism* / Q000382:microbiology; D004269:DNA, Bacterial / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; C429018:NOD2 protein, human; D053473:Nod2 Signaling Adaptor Protein