title: Aberrant mucosal lymphocyte number and subsets in the colon of post-infectious irritable bowel syndrome patients.
abstract: BACKGROUND
  Irritable bowel syndrome (IBS) is characterized by chronic abdominal symptoms such as pain, discomfort, and altered bowel habits. A subset of IBS patients, denoted as post-infectious IBS (PI-IBS) patients, develop symptoms after an enteric infection. Distinct abnormalities in the gut mucosa, including mucosal inflammation, have been proposed to contribute to or be the cause of PI-IBS. This study investigated lymphocyte subsets in PI-IBS patients compared to healthy controls.
  
  
  METHODS
  Ten PI-IBS patients and nine healthy controls participated. All PI-IBS patients met the Rome III diagnostic criteria for IBS and reported sustained symptoms at least 1 year after an episode of acute gastroenteritis. Intraepithelial lymphocytes and lamina propria lymphocytes (LPLs), isolated from mucosal tissue samples, were stained and analyzed for a comprehensive set of cell markers using flow cytometry.
  
  
  RESULTS
  The number of LPLs in PI-IBS was significantly increased compared to those in healthy controls (p < 0.05). PI-IBS patients showed significantly increased proportions of CD45RO(+) CD4(+) activated/memory T cells (p < 0.05) and double-positive CD4(+) CD8(+) cells (p < 0.05), respectively, in the lamina propria. The number of CD19(+) LPLs was decreased in PI-IBS patients compared to healthy controls (p < 0.001).
  
  
  CONCLUSIONS
  This study presents new evidence that PI-IBS is associated with a sustained aberrant mucosal immune response and support future studies of anti-inflammatory or immune-modulating treatments in these patients.
authors.affiliation: School of Health and Medical Sciences, Örebro University , Örebro , Sweden.
authors.forename: Johanna
authors.initials: J
authors.lastname: Sundin
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rangel
authors.forename: Ashok K
authors.initials: AK
authors.lastname: Kumawat
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Hultgren-Hörnquist
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Brummer
mesh_terms: D000328:Adult; D018941:Antigens, CD19 / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016827:CD8 Antigens / Q000032:analysis; D016022:Case-Control Studies; D003106:Colon / Q000276:immunology*; D005260:Female; D051858:Forkhead Transcription Factors / Q000032:analysis; D005759:Gastroenteritis / Q000150:complications* / Q000382:microbiology; D006801:Humans; D018928:Immunity, Mucosal; D007413:Intestinal Mucosa / Q000276:immunology* / Q000473:pathology; D043183:Irritable Bowel Syndrome / Q000276:immunology* / Q000473:pathology; D019394:Ki-67 Antigen / Q000032:analysis; D017493:Leukocyte Common Antigens / Q000032:analysis; D008297:Male; D008875:Middle Aged; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D055815:Young Adult
chemical_list: D018941:Antigens, CD19; D017252:CD3 Complex; D016827:CD8 Antigens; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D019394:Ki-67 Antigen; D017493:Leukocyte Common Antigens
keywords: cell biology; gastrointestinal; health economy; immunology; infections