Colonic immune cells in irritable bowel syndrome: A systematic review and meta-analysis.

C H Choi, G Barbara, K A Sharkey, M Simren, R W McCallum, M J Schmulson, L Ohman, L Chang, M Coëffier, O Y Lee, M Bashashati, Z X Bian, P A Hughes, N Rezaei, G Talmon, S Moraveji, M R Barbaro, C Cremon, S Moossavi

Journal: Neurogastroenterology and motility 2018;30(1):

PMID: 28851005

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Abstract

BACKGROUND & AIMS

Increases in mucosal immune cells have frequently been observed in irritable bowel syndrome (IBS) patients. However, this finding is not completely consistent between studies, possibly due to a combination of methodological variability, population differences and small sample sizes. We performed a meta-analysis of case-control studies that compared immune cell counts in colonic biopsies of IBS patients and controls.

METHODS

PubMed and Embase were searched in February 2017. Results were pooled using standardized mean difference (SMD) and were considered significant when zero was not within the 95% confidence interval (CI). Heterogeneity was assessed based on I statistics where I ≤ 50% and I > 50% indicated fixed and random effect models, respectively.

KEY RESULTS

Twenty-two studies on 706 IBS patients and 401 controls were included. Mast cells were increased in the rectosigmoid (SMD: 0.38 [95% CI: 0.06-0.71]; P = .02) and descending colon (SMD: 1.69 [95% CI: 0.65-2.73]; P = .001) of IBS patients. Increased mast cells were observed in both constipation (IBS-C) and diarrhea predominant IBS (IBS-D). CD3 T cells were increased in the rectosigmoid (SMD: 0.53 [95% CI: 0.21-0.85]; P = .001) and the descending colon of the IBS patients (SMD: 0.79, 95% CI [0.28-1.30]; P = .002). This was possibly in relation to higher CD4 T cells in IBS (SMD: 0.33 [95% CI: 0.01-0.65]; P = .04) as there were no differences in CD8 T cells.

CONCLUSIONS & INFERENCES

Mast cells and CD3 T cells are increased in colonic biopsies of patients with IBS vs non-inflamed controls. These changes are segmental and sometimes IBS-subtype dependent. The diagnostic value of the quantification of colonic mucosal cells in IBS requires further investigation.

Address: Division of Gastroenterology, Department of Internal Medicine, Texas Tech University Health Sciences Center/Paul L. Foster School of Medicine, El Paso, TX, USA.; Digestive Oncology Research Center, Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran.; Department of Medical Microbiology, University of Manitoba, Winnipeg, MB, Canada.; Department of Medical and Surgical Sciences, Centre for Applied Biomedical Research, University of Bologna, Bologna, Italy.; Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA.; Fred and Pamela Buffet Cancer Center, Omaha, NE, USA.; Research Center for Immunodeficiencies, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran.; Centre for Nutritional and Gastrointestinal Diseases, Department of Medicine, University of Adelaide and South Australian Health Medical Health Research Institute, Adelaide, SA, Australia.; School of Chinese Medicine, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, China.; Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea.; Department of Internal Medicine, Hanyang University College of Medicine, Seoul, Korea.; Normandie Univ, INSERM unit 1073 "Nutrition, inflammation and brain-gut axis", Institute for Research and Innovation in Biomedicine, Rouen Medical University and Rouen University Hospital, Rouen, France.; G Oppenheimer Center of Neurobiology of Stress and Resilience, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.; Departments of Internal Medicine and Clinical Nutrition and Microbiology and Immunology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.; Laboratorio de Hígado, Páncreas y Motilidad (HIPAM), Unidad de Investigación en Medicina Experimental, Facultad de Medicina-Universidad Nacional Autónoma de México (UNAM), Hospital General de México, Mexico City, Mexico.; Department of Internal Medicine & Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.; Center for Functional GI and Motility Disorders, University of North Carolina, Chapel Hill, NC, USA.; Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada.

DOI: 10.1111/nmo.13192