title: Serological responses to microbial antigens in celiac disease patients during a gluten-free diet.
abstract: BACKGROUND
  Immunoglobulin A (IgA) autoantibodies to tissue transglutaminase (tTG) are commonly used for screening and diagnosing of celiac disease (CD). Seroreactivity for anti-Saccharomyces cerevisiae antibody (ASCA) and bacterial antigens have also been detected in CD patients. The aim of this study was to examine prospectively serologic responses to microbial targets in adult CD patients at the time of diagnosis and during a gluten-free diet (GFD). Further, we wanted to evaluate whether these serologic specificities could provide new tools for the follow-up of CD patients.
  
  
  METHODS
  Data on 55 adult biopsy-proven CD patients were available for follow-up study. Upper gastrointestinal endoscopy was performed on all patients. Sera from patients were tested for antibodies to tTG and ASCA and additionally analyzed with IgA enzyme-linked immunosorbent assays to Pseudomonas fluorescens-associated sequence, I2, and to a Bacteroides caccae TonB-linked outer membrane protein, OmpW.
  
  
  RESULTS
  At the time of diagnosis, 91% of CD cases were positive for tTG and 49% for ASCA; positive seroreactivity to I2 was found in 86% and to OmpW in 60% of CD patients at the time of diagnosis. The frequency of seropositivity and serum levels of these antibodies decreased during GFD. Moreover, we found that the decline in the serum levels was significant in all of these markers (p < 0.005). Interestingly, we also found that serum levels of ASCA correlated with the grade of mucosal morphology (p = 0.021), as the ASCA serum levels declined in accordance with mucosal healing.
  
  
  CONCLUSIONS
  Commensal enteric bacteria seem to play a role in the small intestinal mucosal damage in CD. This was proven by the serological responses to different microbial antigens shown in this study. Serum levels of ASCA, anti-I2, and anti-OmpW antibodies decreased significantly during GFD, indicating that these serologic markers are gluten dependent in CD patients. These specificities could provide new tools in the follow-up of CD patients.
authors.affiliation: Paediatric Research Centre and Medical School, University of Tampere and Tampere University Hospital, Tampere, Finland.
authors.forename: Sara
authors.initials: S
authors.lastname: Ashorn
authors.forename: Tuuli
authors.initials: T
authors.lastname: Välineva
authors.forename: Katri
authors.initials: K
authors.lastname: Kaukinen
authors.forename: Merja
authors.initials: M
authors.lastname: Ashorn
authors.forename: Jonathan
authors.initials: J
authors.lastname: Braun
authors.forename: Hanna
authors.initials: H
authors.lastname: Raukola
authors.forename: Immo
authors.initials: I
authors.lastname: Rantala
authors.forename: Pekka
authors.initials: P
authors.lastname: Collin
authors.forename: Markku
authors.initials: M
authors.lastname: Mäki
authors.forename: Tiina
authors.initials: T
authors.lastname: Luukkaala
authors.forename: Sari
authors.initials: S
authors.lastname: Iltanen
mesh_terms: D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D000908:Antibodies, Fungal / Q000097:blood*; D000942:Antigens, Bacterial / Q000276:immunology; D001425:Bacterial Outer Membrane Proteins / Q000097:blood; D001439:Bacteroides / Q000276:immunology; D002446:Celiac Disease / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D055050:Diet, Gluten-Free; D005260:Female; D005500:Follow-Up Studies; D005983:Glutens / Q000276:immunology; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011551:Pseudomonas fluorescens / Q000276:immunology; D012441:Saccharomyces cerevisiae / Q000276:immunology*; D018089:Superantigens / Q000097:blood; D011503:Transglutaminases / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000908:Antibodies, Fungal; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; C437325:OmpW protein, Bacteroides caccae; C469916:PfiT protein, Pseudomonas fluorescens; D018089:Superantigens; D005983:Glutens; D011503:Transglutaminases