Influence of Helicobacter pylori on cytokine regulation in chronic atrophic gastritis

Abstract

At present, the level of Helicobacter pylori infection is determined by geographic area, gender and age of the examined individuals, and can reach up to 95% of the total population. Environmental adaptation of H. pylori is exhibited in its ability to adhere to the gastric mucosal epithelium and modulated expression of its own virulent factors. Current concepts implicate that H. pylori can survive inside epithelial cells, evading host immune response. Cytokines are produced by immune cells and act to regulate its major stages. A cytokine cascade launched after Helicobacter pylori infection triggers immune reactions, progression of chronic inflammatory and destructive processes in the gastric mucosa. The role of cytokines in precancerous diseases of the stomach is ambiguous because, on the one hand, they activate immune response aimed at eliminating the pathogen, whereas on the other hand, they do contribute to the disease progression. The aim of our study was to examine profile of some cytokines and features of cytokine regulation in H. pylori-infected middle-aged males with chronic gastritis (CG) as well as chronic atrophic gastritis (CAG). In patients with CG with H. pylori, CAG and CAG with H. pylori, an increase in the cytokine IL-2 was observed that might contribute to augmented damaging effect of cytotoxic lymphocytes, as well as implementation of antitumor effect. CAG with H. pylori was featured with IL-8 hyperproduction, which resulted in increased absolute numbers of band neutrophils in peripheral blood and their decreased phagocytic activity evidencing about altered host defense mechanisms. There was increased amount of IFNy involved in recognition of malignantly transformed cells and upregulated expression of the major histocompatibility complex molecules on antigen-presenting cells. In patients with CG with H. pylori and CAG with H. pylori, production of IL-4 was increased, which might serve as a contributing factor to the chronicity of H. pylori-associated diseases. Overproduction of type 1 and type 2 cytokines indicates about activated Th1 and Th2 type immune reactions in H. pylori-associat-ed CG. A potent pro-inflammatory cytokine cascade triggers inflammatory changes in gastric mucosa with developing neutrophil infiltration and lymphocyte activation. Damage and death of epithelial cells upon inflammation form erosive and ulcerative defects, or changes manifested as gastric mucosal atrophy, metaplasia and neoplasia. The data obtained may be used as additional diagnostic criteria in early diagnostics of precancerous stomach diseases.