title: Immunoglobulin coating of faecal bacteria in inflammatory bowel disease.
abstract: OBJECTIVE
  An inappropriate mucosal immune response to the commensal bacterial flora may play a role in the pathogenesis of inflammatory bowel disease (IBD). In this study we determined the percentage of immunoglobulin-coated bacteria in the stools of patients and controls.
  
  
  METHODS
  Faecal samples were obtained from 18 patients with IBD (one sample during exacerbation and one shortly after remission was achieved), 15 healthy volunteers, eight infectious colitis patients, and 13 IBD patients in long-term remission. Bacterial immunoglobulin coating was determined by flow-cytometry analysis. Faecal alpha-1-antitrypsin concentrations were determined by radial immune diffusion.
  
  
  RESULTS
  IBD patients had 69 +/- 19% immunoglobulin A (IgA)-, 56 +/- 32% immunoglobulin G (IgG)- and 56 +/- 29% immunoglobulin M (IgM)-coated bacteria in their faeces. Healthy controls had less immunoglobulin coating, respectively 36 +/- 12%, 11 +/- 4% and 11 +/- 7%. Infectious colitis patients had 57 +/- 14% IgA, 31 +/- 13% IgG, and 42 +/-16% IgM; however, they had higher faecal alpha-1-antitrypsin concentrations than IBD patients. Shortly after remission, IBD patients had 65 +/- 20% IgA, 32 +/- 18% IgG and 40 +/- 21% IgM. Long-term-remission IBD patients had normal IgG and IgM but increased IgA (50 +/- 16%) coating.
  
  
  CONCLUSIONS
  Compared with healthy controls, patients with IBD had an increased percentage of immunoglobulin-coated faecal anaerobic bacteria, both in active disease and shortly after remission. These results support the concept that there may be a breakdown of mucosal tolerance to the commensal gut flora in IBD.
authors.affiliation: Department of Internal Medicine--Gastroenterology Section, University of Groningen, Groningen, The Netherlands. l.a.vdwaaij@mzh.nl
authors.forename: Laurens A
authors.initials: LA
authors.lastname: van der Waaij
authors.forename: Frans G M
authors.initials: FG
authors.lastname: Kroese
authors.forename: Annie
authors.initials: A
authors.lastname: Visser
authors.forename: Gerardus F
authors.initials: GF
authors.lastname: Nelis
authors.forename: Bram D
authors.initials: BD
authors.lastname: Westerveld
authors.forename: Peter L M
authors.initials: PL
authors.lastname: Jansen
authors.forename: John O
authors.initials: JO
authors.lastname: Hunter
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000032:analysis*; D001419:Bacteria / Q000276:immunology*; D003092:Colitis / Q000276:immunology / Q000382:microbiology; D005243:Feces / Q000201:enzymology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007108:Immune Tolerance; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D007136:Immunoglobulins / Q000032:analysis*; D015212:Inflammatory Bowel Diseases / Q000276:immunology* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D013559:Symbiosis / Q000276:immunology; D000515:alpha 1-Antitrypsin / Q000032:analysis
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; C043392:SERPINA1 protein, human; D000515:alpha 1-Antitrypsin