Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 14, 2023; 29(30): 4604-4615
Published online Aug 14, 2023. doi: 10.3748/wjg.v29.i30.4604
Immune response modulation in inflammatory bowel diseases by Helicobacter pylori infection
Gabriella Feilstrecker Balani, Mariana dos Santos Cortez, Jayme Euclydes Picasky da Silveira Freitas, Fabrício Freire de Melo, Ana Carla Zarpelon-Schutz, Kádima Nayara Teixeira
Gabriella Feilstrecker Balani, Mariana dos Santos Cortez, Jayme Euclydes Picasky da Silveira Freitas, Ana Carla Zarpelon-Schutz, Kádima Nayara Teixeira, Campus Toledo, Universidade Federal do Paraná, Toledo 85.919-899, Paraná, Brazil
Fabrício Freire de Melo, Campus Anísio Teixeira, Universidade Federal da Bahia, Instituto Multidisciplinar em Saúde, Vitória da Conquista 45.029-094, Bahia, Brazil
Ana Carla Zarpelon-Schutz, Programa de Pós-graduação em Biotecnologia - Setor Palotina, Universidade Federal do Paraná, Palotina 85.950-000, Paraná, Brazil
Kádima Nayara Teixeira, Programa Multicêntrico de Pós-graduação em Bioquímica e Biologia Molecular - Setor Palotina, Universidade Federal do Paraná, Palotina 85.950-000, Paraná, Brazil
Author contributions: Feilstrecker Balani G, Picasky da Silveira Freitas JE, dos Santos Cortez M collected the data and wrote the manuscript; Freire de Melo F performed the critical analysis of the manuscript; Zarpelon-Schutz AC and Teixeira KN performed the critical analysis, corrected the manuscript and coordinated the study; and all authors approved the final version of the manuscript.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Kádima Nayara Teixeira, PhD, Professor, Campus Toledo, Universidade Federal do Paraná, Max Planck 3796, Toledo 85.919-899, Paraná, Brazil.
Received: April 28, 2023
Peer-review started: April 28, 2023
First decision: June 17, 2023
Revised: July 1, 2023
Accepted: July 24, 2023
Article in press: July 24, 2023
Published online: August 14, 2023

Many studies point to an association between Helicobacter pylori (H. pylori) infection and inflammatory bowel diseases (IBD). Although controversial, this association indicates that the presence of the bacterium somehow affects the course of IBD. It appears that H. pylori infection influences IBD through changes in the diversity of the gut microbiota, and hence in local chemical characteristics, and alteration in the pattern of gut immune response. The gut immune response appears to be modulated by H. pylori infection towards a less aggressive inflammatory response and the establishment of a targeted response to tissue repair. Therefore, a T helper 2 (Th2)/macrophage M2 response is stimulated, while the Th1/macrophage M1 response is suppressed. The immunomodulation appears to be associated with intrinsic factors of the bacteria, such as virulence factors - such oncogenic protein cytotoxin-associated antigen A, proteins such H. pylori neutrophil-activating protein, but also with microenvironmental changes that favor permanence of H. pylori in the stomach. These changes include the increase of gastric mucosal pH by urease activity, and suppression of the stomach immune response promoted by evasion mechanisms of the bacterium. Furthermore, there is a causal relationship between H. pylori infection and components of the innate immunity such as the NLR family pyrin domain containing 3 inflammasome that directs IBD toward a better prognosis.

Keywords: Cytotoxin-associated antigen A oncoprotein, Gut microbiota, Helicobacter pylori, Helicobacter pylori neutrophil-activating protein, Immunological modulation, Inflammatory bowel disease, NLR family pyrin domain containing 3 inflammasome

Core Tip:Helicobacter pylori (H. pylori) infection seems to modulate the immune response triggered by inflammatory bowel disease in a way that makes it less aggressive. The virulence factors of H. pylori, as well as the mechanisms that allow it to remain in the stomach environment, appear to change the intestinal microenvironment and modulate the local immune response, contributing to a disease with milder symptoms and less tissue damage.