Immunological mechanisms of the development of autoimmune gastritis as a precancerous disease of the stomach

Background. The gastrointestinal tract is considered the largest immunological organ, as it contains 70% of the body’s lymphocyte population. The prevalence of concomitant autoimmune diseases in patients with autoimmune arthritis reaches 40%, and the most common diseases are thyroid gland diseases, type 1 diabetes, hemolytic anemia, rheumatoid arthritis, autoimmune hepatitis, myasthenia gravis, Sjogren’s disease, etc. Immune dysregulation plays a key role in the pathogenesis of not only autoimmune diseases, but also neoplastic processes. Purpose – summarize current information about autoimmune gastritis as a precancerous condition, according to open sources of information. Materials and Methods. Publications were selected based on PubMed, Clinical Key Elsevier, Cochrane Library, eBook Business Collection and Google Scholar databases, which covered information on the assessment of the quality of medical care. At the first stage, literature sources were searched for Keywords: autoimmune gastritis, gastric mucosa, ham cancer. At the second stage, summaries of articles were studied and publications that did not meet the research criteria were excluded. At the third stage, the full texts of the selected articles were studied for compliance with the criteria for inclusion in the literature list and research relevance. Results. Isolation of a separate form of gastritis that leads to the development of B12-deficient anemia – autoimmune gastritis became possible due to the identification of autoantibodies to autoantigens, in particular antibodies to parietal cells and H+/K+-adenosine triphosphate enzyme in the stomach. Autoimmune gastritis is an organ-specific autoimmune disease characterized by chronic inflammation of the gastrointestinal tract, which develops into atrophic gastritis, which causes malabsorption of necessary elements and, ultimately, anemia. Chronic inflammation is now considered an important mechanism for the initiation of carcinogenesis, causing, in particular, hepatocellular carcinoma in patients with hepatitis, colon cancer in inflammatory bowel diseases (in particular, ulcerative colitis), and secondary gastric cancer due to gastritis as the most typical examples. The most convincing examples of carcinogenesis caused by chronic inflammation are observed in the gastrointestinal tract, where the risk of carcinogenesis increases in the presence of chronic inflammatory conditions, such as esophagitis, gastritis, colitis, pancreatitis, hepatitis, etc. Stomach cancer is the fifth most common type of cancer and the third leading cause of death from cancer in the world. The five-year survival rate for patients with gastric cancer is 95–99% if the disease is diagnosed at a resectable stage. Conclusions. CD4+ T cells and CD8+T cells jointly support the adaptive immune homeostasis of OSH. OSA atrophy due to autoimmune inflammation refers to precancerous changes and increases the risk of developing adenocarcinoma. Long-term hypo- and achlorhydria is associated with an increase in the serum level of gastrin, which stimulates the proliferation and hyperplasia of enterochromaffin-like cells, which, in turn, can contribute to the development of neuroendocrine tumors of the stomach.