title: Cytokine Response after Stimulation with Key Commensal Bacteria Differ in Post-Infectious Irritable Bowel Syndrome (PI-IBS) Patients Compared to Healthy Controls.
abstract: BACKGROUND
  Microbial dysbiosis and prolonged immune activation resulting in low-grade inflammation and intestinal barrier dysfunction have been suggested to be underlying causes of post-infectious irritable bowel syndrome (PI-IBS). The aim of this study was to evaluate the difference in cytokine response between mucosal specimens of PI-IBS patients and healthy controls (HC) after ex vivo stimulation with key anaerobic bacteria.
  
  
  METHODS
  Colonic biopsies from 11 PI-IBS patients and 10 HC were stimulated ex vivo with the commensal bacteria Bacteroides ovatus, Ruminococcus gnavus, Akkermansia muciniphila, Subdoligranulum variabile and Eubacterium limosum, respectively. The cytokine release (IL-1β, IL-2, IL-8, IL-10, IL-13, IL-17, TNF-α and IFN-γ) in stimulation supernatants was analyzed using the LUMINEX assay. Comparison of cytokine release between PI-IBS patients and healthy controls was performed taking both unstimulated and bacterially stimulated mucosal specimens into account.
  
  
  RESULTS
  IL-13 release from mucosal specimens without bacterial stimulation was significantly lower in PI-IBS patients compared to HC (p < 0.05). After stimulation with Subdoligranulum variabile, IL-1β release from PI-IBS patients was significantly increased compared to HC (p < 0.05). Stimulation with Eubacterium limosum resulted in a significantly decreased IL-10 release in HC compared to PI-IBS patients (p < 0.05) and a tendency to decreased IL-13 release in HC compared to PI-IBS patients (p = 0.07).
  
  
  CONCLUSIONS
  PI-IBS patients differ from HC with regard to cytokine release ex vivo after stimulation with selected commensal bacteria. Hence, our results support that the pathogenesis of PI-IBS comprises an altered immune response against commensal gut microbes.
authors.affiliation: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Johanna
authors.initials: J
authors.lastname: Sundin
authors.affiliation: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Rangel
authors.affiliation: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Dirk
authors.initials: D
authors.lastname: Repsilber
authors.affiliation: School of Health and Medical Sciences, Faculty of Medicine and Health, Örebro University, Örebro, Sweden.
authors.forename: Robert-Jan
authors.initials: RJ
authors.lastname: Brummer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D016207:Cytokines / Q000235:genetics / Q000378:metabolism*; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000276:immunology*; D006801:Humans; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism; D043183:Irritable Bowel Syndrome / Q000276:immunology* / Q000382:microbiology; D008297:Male; D008875:Middle Aged
chemical_list: D016207:Cytokines