title: Subclinical mucosal inflammation in diarrhea-predominant irritable bowel syndrome (IBS) in a tropical setting.
abstract: OBJECTIVE
  There is evidence for low-grade inflammation in the pathophysiology of post-infectious irritable bowel syndrome (IBS). We assessed the degree of subclinical intestinal mucosal inflammation in diarrhea-predominant IBS (IBS-D) in a tropical setting.
  
  
  METHODS
  In a prospective study over 1 year, we investigated 49 patients with IBS-D (cases; median age 34 years (range 18-59); M:F 36:13), diagnosed on Rome III criteria. 14 individuals with a family history of colon cancer (median age 46.5 years (range 23-56); M:F 6:8) were selected as controls. Stools of cases and controls were tested for calprotectin. During colonoileoscopy, serial biopsies were obtained. Mucosal mast cells, neutrophils, eosinophils and lymphocytes/plasma cell infiltrate were quantified. Tissue expression of IL-8 and IL-10 was assessed in biopsies by semi-quantitative RT-PCR.
  
  
  RESULTS
  A history suggestive of an episode of infectious diarrhea (ID) was present in 16/49 cases and 0/14 controls (p = 0.013). In cases, there were significantly more mucosal mast cells in the ileum and all segments of colon and significantly more eosinophils in the cecum. Tissue expression of IL-8 was significantly higher and IL-10 significantly lower in cases compared with controls (target/standard cDNA ratio, median (range) IL-8: 1.25 (0.75-2) vs. 0.85 (0.63-1.3), p < 0.0001, Mann-Whitney U test; IL-10: 0.33 (0-0.63) vs. 0.55 (0.5-0.7), p < 0.0001). There was a significant inverse correlation between IL-8 and IL-10 expression (Pearson correlation, (-) 0.509; p < 0.01).
  
  
  CONCLUSIONS
  There was evidence of subclinical intestinal mucosal inflammation in patients with IBS-D. The finding of increased eosinophils is novel, and may be of special relevance to IBS-D in the tropics.
authors.affiliation: Department of Medicine, Faculty of Medicine, University of Kelaniya, Ragama, Sri Lanka. apdsilva@yahoo.com
authors.forename: Arjuna Priyadarsin
authors.initials: AP
authors.lastname: De Silva
authors.forename: Shanika Dulanjalee
authors.initials: SD
authors.lastname: Nandasiri
authors.forename: Janaki
authors.initials: J
authors.lastname: Hewavisenthi
authors.forename: Aresha
authors.initials: A
authors.lastname: Manamperi
authors.forename: Madurangi Prasadi
authors.initials: MP
authors.lastname: Ariyasinghe
authors.forename: Anuradha Supun
authors.initials: AS
authors.lastname: Dassanayake
authors.forename: Derek P
authors.initials: DP
authors.lastname: Jewell
authors.forename: Hithanadura Janaka
authors.initials: HJ
authors.lastname: de Silva
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001706:Biopsy; D016022:Case-Control Studies; D003106:Colon / Q000378:metabolism / Q000473:pathology*; D003113:Colonoscopy; D003967:Diarrhea; D004804:Eosinophils / Q000378:metabolism; D005260:Female; D005759:Gastroenteritis / Q000150:complications*; D006801:Humans; D007082:Ileum / Q000378:metabolism / Q000473:pathology*; D016753:Interleukin-10 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology*; D043183:Irritable Bowel Syndrome / Q000209:etiology* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013188:Sri Lanka; D014329:Tropical Climate; D055815:Young Adult
chemical_list: D015415:Biomarkers; D016209:Interleukin-8; D016753:Interleukin-10