title: Activation of the mucosal immune system in irritable bowel syndrome.
abstract: OBJECTIVE
  A role for the mucosal immune system in the pathogenesis of irritable bowel syndrome is suggested by its association with intestinal infections.
  
  
  METHODS
  To investigate this, we performed histologic and immunohistologic studies on colonoscopic biopsy specimens from 77 patients with symptoms satisfying the Rome criteria and 28 asymptomatic control patients.
  
  
  RESULTS
  Histologic assessment of biopsy specimens from symptomatic patients indicated 3 different groups. The first (38 of 77) had normal conventional histology; however, immunohistology showed increased intraepithelial lymphocytes (median, 1.8-fold; range, 1.74-1.86), lamina propria CD3(+) cells (2-fold; range, 1.55-2.91), and CD25(+) cells (6.5-fold; range, 4.98-8.13) compared with asymptomatic controls. The second group (31 of 77) had nonspecific microscopic inflammation and on immunohistology showed similar increases in lymphocyte populations (not significant vs. the uninflamed group) as well as increased numbers of neutrophil leukocytes and mast cells (P < 0.0001 vs. controls and the uninflamed group). The third group (8 of 77) fulfilled histologic and immunohistologic criteria for classic lymphocytic colitis.
  
  
  CONCLUSIONS
  Examination of colonoscopic biopsy specimens from patients meeting the Rome criteria for a clinical diagnosis of irritable bowel syndrome showed subgroups with normal and abnormal conventional histology. All groups showed increased numbers of activated immunocompetent cells in the intestinal mucosa on quantitative immunohistology, implicating the mucosal immune system in pathogenesis.
authors.affiliation: Wakefield Gastroenterology Centre and Research Institute, Wakefield Hospital, Wellington, New Zealand. vchadwick@clear.net.nz
authors.forename: Vinton S
authors.initials: VS
authors.lastname: Chadwick
authors.forename: Wangxue
authors.initials: W
authors.lastname: Chen
authors.forename: Dairu
authors.initials: D
authors.lastname: Shu
authors.forename: Barbara
authors.initials: B
authors.lastname: Paulus
authors.forename: Peter
authors.initials: P
authors.lastname: Bethwaite
authors.forename: Andy
authors.initials: A
authors.lastname: Tie
authors.forename: Ian
authors.initials: I
authors.lastname: Wilson
mesh_terms: D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D001706:Biopsy; D003106:Colon / Q000473:pathology; D003109:Colonic Diseases, Functional / Q000473:pathology / Q000503:physiopathology*; D003113:Colonoscopy; D005260:Female; D006801:Humans; D007107:Immune System / Q000473:pathology / Q000503:physiopathology*; D007158:Immunologic Techniques; D007413:Intestinal Mucosa / Q000276:immunology* / Q000473:pathology; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D008875:Middle Aged
chemical_list: D015703:Antigens, CD