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World J Gastroenterol. Jan 28, 2022; 28(4): 402-411
Published online Jan 28, 2022. doi: 10.3748/wjg.v28.i4.402
Helicobacter pylori infection: How does age influence the inflammatory pattern?
Glauber Rocha Lima Araújo, Hanna Santos Marques, Maria Luísa Cordeiro Santos, Filipe Antônio França da Silva, Breno Bittencourt da Brito, Gabriel Lima Correa Santos, Fabrício Freire de Melo
Glauber Rocha Lima Araújo, Maria Luísa Cordeiro Santos, Filipe Antônio França da Silva, Breno Bittencourt da Brito, Gabriel Lima Correa Santos, Fabrício Freire de Melo, Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Vitória da Conquista 45029-094, Brazil
Hanna Santos Marques, Campus Vitória da Conquista, Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista 45083-900, Brazil
Author contributions: All authors equally contributed to this paper with conception and design of the study, literature review and analysis, drafting, critical revision, and editing of the manuscript, and final approval of the final version.
Conflict-of-interest statement: All authors declare no potential 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: Fabrício Freire de Melo, PhD, Professor, Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Instituto Multidisciplinar em Saúde, Universidade Federal da Bahia, Rua Hormindo Barros, 58, Quadra 17, Lote 58, Vitória da Conquista 45029-094, Brazil.
Received: March 20, 2021
Peer-review started: March 20, 2021
First decision: June 14, 2021
Revised: June 21, 2021
Accepted: January 13, 2022
Article in press: January 13, 2022
Published online: January 28, 2022

The inflammatory pattern during Helicobacter pylori (H. pylori) infection is changeable and complex. During childhood, it is possible to observe a predominantly regulatory response, evidenced by high concentrations of key cytokines for the maintenance of Treg responses such as TGF-β1 and IL-10, in addition to high expression of the transcription factor FOXP3. On the other hand, there is a predominance of cytokines associated with the Th1 and Th17 responses among H. pylori-positive adults. In the last few years, the participation of the Th17 response in the gastric inflammation against H. pylori infection has been highlighted due to the high levels of TGF-β1 and IL-17 found in this infectious scenario, and growing evidence has supported a close relationship between this immune response profile and unfavorable outcomes related to the infection. Moreover, this cytokine profile might play a pivotal role in the effectiveness of anti-H. pylori vaccines. It is evident that age is one of the main factors influencing the gastric inflammatory pattern during the infection with H. pylori, and understanding the immune response against the bacterium can assist in the development of alternative prophylactic and therapeutic strategies against the infection as well as in the comprehension of the pathogenesis of the outcomes related to that microorganism.

Keywords: Helicobacter pylori, Inflammation, Treg response, Th1 response, Th17 response, Gastric diseases

Core Tip: Helicobacter pylori (H. pylori) is a bacterium acquired mainly in childhood that increases the risk of developing certain gastric diseases. However, the main complications are noticed predominantly in adulthood. This can be explained based on the gastric inflammatory pattern against the pathogen, which changes as long as the infected individual gets older, favoring, during childhood, the persistence of the infection and then, in adulthood, the gastric damage. This article discusses the factors that can influence the gastric inflammatory pattern in individuals infected with H. pylori.