title: A pilot study of colonic B cell pattern in irritable bowel syndrome.
abstract: OBJECTIVE
  Low-grade gastrointestinal inflammation has been reported in patients with irritable bowel syndrome (IBS). However, the colonic B-cell pattern has not been investigated in these patients. Therefore, the aim of this pilot study was to investigate the distribution and isotype of immunoglobulin-producing B cells in the colonic mucosa of IBS patients.
  
  
  METHODS
  Patients with IBS (n=12) fulfilling the Rome II criteria were compared with controls (n=11). Immunohistochemical staining of biopsies from the sigmoid and ascending colon was performed.
  
  
  RESULTS
  The number of IgA(+) B cells in the ascending colon was lower in IBS patients than in controls (p=0.039). Furthermore, unlike controls, IBS patients had a reduction of IgA(+) B cells in the ascending colon relative to the sigmoid colon (p=0.04). Neither the IgG(+), nor the IgM(+) colonic B-cell numbers differed between IBS patients and controls. Very few colonic IgE(+) cells were detected and there was no difference between the two subject groups.
  
  
  CONCLUSIONS
  The reduced number of colonic IgA(+) B cells in IBS patients suggests that the disorder may be associated with a modified gut immune defence. Whether this phenomenon is causally related to symptoms remains unknown and merits further investigation in a larger group of patients.
authors.affiliation: Department of Medicine, Sahlgrenska Academy of Göteborg University, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Forshammar
authors.forename: Stefan
authors.initials: S
authors.lastname: Isaksson
authors.forename: Hans
authors.initials: H
authors.lastname: Strid
authors.forename: Per-Ove
authors.initials: PO
authors.lastname: Stotzer
authors.forename: Henrik
authors.initials: H
authors.lastname: Sjövall
authors.forename: Magnus
authors.initials: M
authors.lastname: Simrén
authors.forename: Lena
authors.initials: L
authors.lastname: Ohman
mesh_terms: D000328:Adult; D001402:B-Lymphocytes / Q000276:immunology*; D003106:Colon / Q000276:immunology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A; D007073:Immunoglobulin E; D007075:Immunoglobulin M; D007249:Inflammation / Q000276:immunology*; D043183:Irritable Bowel Syndrome / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects
chemical_list: D007070:Immunoglobulin A; D007075:Immunoglobulin M; D007073:Immunoglobulin E