An interventional study of Elimination and re-introduction of CLE or COLAP positive food item(s) in Irritable Bowel Syndrome and Food Sensitivity, sponsored by Magnus Simrén. Recruiting at 1 site in Sweden. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-06-29.
Sponsored by Magnus Simrén · Not applicable, Interventional, and Treatment
The aim of this study is to define local immune responses in the GI tract to food antigens in IBS patients, with and without Brachyspira infection, using advanced imaging. We hypothesize that Brachyspira infection can cause IBS symptoms by inducing loss of oral tolerance to dietary antigens through development of food-specific intestinal immune reactions and subsequent development of visceral hypersensitivity.
During this study, the investigators will perform confocal laser endomiscroscopy (CLE) and/or colonoscopic antigen provocation test (COLAP) to test to which food items the participants react to. Furthermore, the investigators will perform rectal barostat examination and a sigmoidoscopy without laxatives. The investigators will collect biological samples and the participants will complete several questionnaires.
The aim of this study is to define local immune responses in the GI tract to food antigens in IBS patients with and without Brachyspira infection using advanced imaging. The investigators hypothesize that Brachyspira infection can cause IBS symptoms by inducing loss of oral tolerance to dietary antigens through development of food-specific intestinal immune reactions and subsequent development of visceral hypersensitivity.
Visit 1: inclusion, questionnaires, blood, rectal barostat examination Visit 2: questionnaires, blood, stool, diaries (food and stool), sigmoidoscopy (without laxantives) Allergologist visit (skin prick test and interpretation blood results) Visit 3A: stool, confocal laser endomicroscopy (CLE) OR colonoscopic antigen provocation test (COLAP) Visit 3B: facultative: in a subset of individuals, both CLE and COLAP will be performed (during separate visits)
Visit 4,5 and 6 only if the CLE or COLAP was positive for (at least) 1 food item
Visit 4: questionnaires and dietician-led instruction which food item to exclude (positive food item(s) during CLE/COLAP,), exclusion for 4 weeks. If both CLE and COLAP are positive, the diet will be COLAP-based.
Visit 5: questionnaires, stool diary, instructions re-introduction food item(s) Visit 6: questionnaires
QUESTIONNAIRES Baseline questionnaires; demographic, symptoms, symptom/medication/diet history, co-morbid medical conditions
IBS symptoms: IBS-Symptom Severity Scale (IBS-SSS) and Gastrointestinal Symptom Rating Scale (GSRS)-IBS
Psychological distress: Hospital Anxiety and Depression Scale (HADS), Patient Health Questionnaire (PHQ)-9 (both visit 1,4,5,6, generalized Anxiety Disorder 7-item scale (GAD-7)
Somatization: PHQ-15 for the number and severity of bodily symptoms.
Gastrointestinal specific anxiety: Visceral Sensitivity Index (VSI).
Sensitivity: Central Sensitization Inventory (CSI).
Food avoidance and restriction: (ARFID).
Stool habits and GI symptoms: 14-day GI symptom diary based on Bristol Stool Form Scale (BSFS).
Quality of life: IBS-Quality of Life (QOL).
Food intake: 4-days food diary, MealQ.
COLONOSCOPIC ALLERGEN PROVOCATION TEST, COLAP:
CONFOCAL LASER ENDOMICROSCOPY, CLE, gastroscopy:
VISCERAL SENSITIVITY:
•Rectal barostat sensitivity measurement: With the rectal barostat, the investigators can measure the rectal sensitivity. A balloon is inserted and inflated in the rectum in a controlled setting. The patient indicates when defined sensory thresholds are reached (first feeling of the balloon, urge to empty bowel, discomfort or pain). When the patient indicates discomfort or pain, or another reason to stop, the balloon inflation will be stopped.
SIGMOIDOSCOPY:
•Flexible sigmoidoscopy without bowel preparation, to interfere as little as possible with the normal gut microenvironment; fresh biopsies for specific analyses and biopsies stored for subsequent analyses.
BIOLOGICAL SAMPLES:
Exclusion Criteria:
The food item(s) which were positive during CLE (fluorescein leakage and cell shedding) or COLAP (swelling).
Other: Elimination and re-introduction of CLE or COLAP positive food item(s)
Elimination (4 weeks) and re-introduction (4 weeks) of all CLE or COLAP positive food item(s)
IBS-SSS (Irritable Bowel Syndrom Severity Scoring System) after exclusion (proportion).
the proportion of participants with an IBS-SSS reduction of ≥50 points, measured before (visit 4) and after (visit 5) exclusion of the CLE or COLAP positive food item(s) (= responders). IBS-SSS: higher IBS-SSS indicate more severe symptoms. Scores ranging 0-500.
Time frame: 4 weeks after exclusion
IBS-SSS (Irritable Bowel Syndrom Severity Scoring System) after exclusion (absolute)
IBS-SSS: absolute change of IBS-SSS, measured before (visit 4) and after (visit 5) EXCLUSION of the CLE or COLAP positive food item(s). Higher IBS-SSS indicate more severe symptoms. Scores ranging 0-500.
Time frame: 4 weeks after exclusion
IBS-SSS (Irritable Bowel Syndrom Severity Scoring System) after reintroduction (proportion)
IBS-SSS: the proportion of participants with an IBS-SSS increase of ≥50 points, measured before (visit 5) and after (visit 6) the REINTRODUCTION of the CLE or COLAP positive food item(s): responders vs non-responders (as based on the primary outcome). Higher IBS-SSS indicate more severe symptoms. Scores ranging 0-500.
Time frame: 4 weeks after reintroduction
IBS-SSS (Irritable Bowel Syndrom Severity Scoring System) after reintroduction (absolute)
IBS-SSS: the absolute change of IBS-SSS, measured before (visit 5) and after (visit 6) the REINTRODUCTION of the CLE or COLAP positive food item(s): total group and responders vs non-responders (as based on the primary outcome)
Time frame: 4 weeks after reintroduction
GSRS-IBS (the Gastrointestinal Symptom Rating Scale Irritable Bowel Syndrome version) after exclusion
change of total and subscores before (visit 4) and after (visit 5) EXCLUSION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher GSRS-IBS indicate more severe symptoms. After calculating of the average scores, those range 1-7.
Time frame: 4 weeks after exclusion
GSRS-IBS (the Gastrointestinal Symptom Rating Scale Irritable Bowel Syndrome version) after reintroduction
change of total and subscores before (visit 5) and after (visit 6) REINTRODUCTION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher GSRS-IBS indicate more severe symptoms. After calculating of the average scores, those range 1-7.
Time frame: 4 weeks after reintroduction
HAD (Hospital Anxiety and Depression scale) after exclusion
change of total and subscores before (visit 4) and after (visit 5) EXCLUSION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher HAD scores indicate more symtoms of anxiety and depression. Total score ranging 0-42 and the two subscores (anxiety and depression) ranging 0-21.
Time frame: 4 weeks after exclusion
HAD (Hospital Anxiety and Depression scale) after reintroduction
change of total and subscores before (visit 5) and after (visit 6) REINTRODUCTION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher HAD scores indicate more symtoms of anxiety and depression. Total score ranging 0-42 and the two subscores (anxiety and depression) ranging 0-21.
Time frame: 4 weeks after reintroduction
PHQ12 (the Patient Health Questionnaire - 12) after exclusion
change of scores before (visit 4) and after (visit 5) EXCLUSION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher PHQ12 scores indicate more bothersome non-GI somatic symptoms. Scores ranging 0-24, with a subanalysis excluding mentrual problems, leading to a range 0-22.
Time frame: 4 weeks after exclusion
PHQ12 (the Patient Health Questionnaire - 12) after reintroduction
change of scores before (visit 5) and after (visit 6) REINTRODUCTION of the CLE or COLAP positive food item(s). Total group and responders vs non-responders (as based on the primary outcome). Higher PHQ12 scores indicate more bothersome non-GI somatic symptoms. Scores ranging 0-24, with a subanalysis excluding mentrual problems, leading to a range 0-22.
Time frame: 4 weeks after reintroduction
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