title: Anti-food and anti-microbial IgG subclass antibodies in inflammatory bowel disease.
abstract: OBJECTIVE
  Inflammatory bowel disease (IBD), particularly Crohn's disease (CD), is associated with increased microbial-specific IgG and IgA antibodies, whereas alterations of anti-food antibodies are still disputed. The knowledge about IgG subclass antibodies in IBD is limited. In this study we analysed IgG subclass antibodies specific for nutritional and commensal antigens in IBD patients and controls.
  
  
  METHODS
  Serum IgG1, IgG2, IgG3 and IgG4 specific for wheat and milk extracts, purified ovalbumin, Escherichia coli and Bacteroides fragilis lysates and mannan from Saccharomyces cerevisiae were analysed by ELISA in patients with CD (n = 56), ulcerative colitis (UC; n = 29), acute gastroenteritis/colitis (n = 12) as well as non-inflammatory controls (n = 62).
  
  
  RESULTS
  Anti-Saccharomyces cerevisiae antibodies (ASCA) of all IgG subclasses and anti-B. fragilis IgG1 levels were increased in CD patients compared to UC patients and controls. The discriminant validity of ASCA IgG2 and IgG4 was comparable with that of ASCA pan-IgG and IgA, whereas it was inferior for ASCA IgG1/IgG3 and anti-B. fragilis IgG1. Complicated CD defined by the presence of perianal, stricturing or penetrating disease phenotypes was associated with increased ASCA IgG1/IgG3/IgG4, anti-B. fragilis IgG1 and anti-E. coli IgG1 levels. Anti-food IgG subclass levels were not different between IBD patients and controls and did not correlate with food intolerance. In contrast to anti-microbial Abs, food-specific IgG responses were predominately of the IgG4 isotype and all food-specific IgG subclass levels correlated negatively with age.
  
  
  CONCLUSIONS
  Our study supports the notion that the adaptive immune recognition of food and commensal antigens are differentially regulated.
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Anke
authors.initials: A
authors.lastname: Jansen
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Ana D
authors.initials: AD
authors.lastname: Mandić
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Eveline
authors.initials: E
authors.lastname: Bennek
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Lisa
authors.initials: L
authors.lastname: Frehn
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Julien
authors.initials: J
authors.lastname: Verdier
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Tebrügge
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Lutz
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Streetz
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Trautwein
authors.affiliation: a Department of Internal Medicine III , University Hospital RWTH Aachen , Aachen , Germany.
authors.forename: Gernot
authors.initials: G
authors.lastname: Sellge
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D000908:Antibodies, Fungal / Q000097:blood*; D001441:Bacteroides fragilis; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004926:Escherichia coli; D005260:Female; D005512:Food Hypersensitivity / Q000097:blood*; D005858:Germany; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D015212:Inflammatory Bowel Diseases / Q000097:blood* / Q000276:immunology; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D008892:Milk / Q000009:adverse effects; D012372:ROC Curve; D012441:Saccharomyces cerevisiae; D014908:Triticum / Q000009:adverse effects; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D000908:Antibodies, Fungal; D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G
keywords: Food intolerance; IgG subclasses; biomarkers; inflammatory bowel disease; microbiota