title: Mucosal immune cell numbers and visceral sensitivity in patients with irritable bowel syndrome: is there any relationship?
abstract: OBJECTIVE
  Repeated exposure to stress leads to mast cell degranulation, microscopic inflammation, and subsequent visceral hypersensitivity in animal models. To what extent this pathophysiological pathway has a role in patients with the irritable bowel syndrome (IBS) has not been properly investigated. The objective of this study was to assess the relationship between visceral hypersensitivity, microscopic inflammation, and the stress response in IBS.
  
  
  METHODS
  Microscopic inflammation of the colonic mucosa was evaluated by immunohistochemistry in 66 IBS patients and 20 healthy volunteers (HV). Rectal sensitivity was assessed by a barostat study using an intermittent pressure-controlled distension protocol. Salivary cortisol to a psychological stress was measured to assess the stress response.
  
  
  RESULTS
  Compared with HV, mast cells, T cells, and macrophages were decreased in IBS patients. Similarly, λ-free light chain (FLC)-positive mast cells were decreased but not immunoglobulin E (IgE)- and IgG-positive mast cells. There were no differences between hypersensitive and normosensitive IBS patients. No relation was found between any of the immune cells studied and the thresholds of discomfort, urge, first sensation, or IBS symptoms (e.g., abdominal pain, stool-related complaints, bloating). Finally, stress-related symptoms and the hypothalamic-pituitary-adrenal-axis response to stress were not correlated with the number of mast cells or the presence of visceral hypersensitivity.
  
  
  CONCLUSIONS
  Although the number of mast cells, macrophages, T cells, and λFLC-positive mast cells is decreased in IBS compared with HV, this is not associated with the presence of visceral hypersensitivity or abnormal stress response. Our data question the role of microscopic inflammation as an underlying mechanism of visceral hypersensitivity, but rather suggest dysregulation of the mucosal immune system in IBS.
authors.affiliation: Department of Gastroenterology and Hepatology, AMC, Amsterdam, The Netherlands.
authors.forename: Breg
authors.initials: B
authors.lastname: Braak
authors.forename: Tamira K
authors.initials: TK
authors.lastname: Klooker
authors.forename: Mira M
authors.initials: MM
authors.lastname: Wouters
authors.forename: Olaf
authors.initials: O
authors.lastname: Welting
authors.forename: Chris M
authors.initials: CM
authors.lastname: van der Loos
authors.forename: Oana I
authors.initials: OI
authors.lastname: Stanisor
authors.forename: Sophie
authors.initials: S
authors.lastname: van Diest
authors.forename: Rene M
authors.initials: RM
authors.lastname: van den Wijngaard
authors.forename: Guy E
authors.initials: GE
authors.lastname: Boeckxstaens
mesh_terms: D000328:Adult; D001707:Biopsy, Needle; D002452:Cell Count; D003106:Colon / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D003113:Colonoscopy; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000276:immunology* / Q000473:pathology; D043183:Irritable Bowel Syndrome / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D008264:Macrophages / Q000276:immunology / Q000473:pathology; D008297:Male; D008407:Mast Cells / Q000276:immunology / Q000473:pathology; D008875:Middle Aged; D011312:Pressure; D012007:Rectum / Q000503:physiopathology*; D012684:Sensory Thresholds; D013315:Stress, Psychological / Q000503:physiopathology; D013601:T-Lymphocytes / Q000276:immunology / Q000473:pathology; D055815:Young Adult
chemical_list: D006854:Hydrocortisone