Morphological features of autoimmune gastritis

Purpose: description and analysis of characteristic morphological criteria of autoimmune gastritis (AIG). Object and methods. The study included 37 patients diagnosed with AIG who were treated at the clinics of I.M. Sechenov Moscow State Medical University in 2022. During the endoscopic examination, biopsies of the gastric mucosa were taken according to the Sydney protocol. The severity of atrophy was assessed using the OLGA system. Additionally, an immunohistochemical study was performed using antibodies to Chromogranin A (5H7, RU, Leica Biosystems, Germany). Results. The average age was 59±12.78 years. 97% of the patients (36 out of 37) were female and 3% (1 out of 37) were male. In biopsies of the antrum of the stomach, grade 1 gastritis was detected in 89.2% of patients (33 cases), while in the stomach body, grade 2 gastritis was noted in 78.4% of samples (29 cases) (chi-squared 9.21, p=0.01). A predominance of the metaplastic type of atrophy of the gastric mucosa was noted in the stomach body: complete intestinal metaplasia (IM) was noted in 59% of biopsies (22 cases), incomplete in 2.7% (1 case). Differences in the degree and stage of AIG depending on the localization of gastritis have been established – lesions of 2 or more degrees/stages in the body of the stomach are significantly more frequent (chi-squared 9.21, p=0.01). Additional histological findings were: the presence of hyperplastic polyps of the stomach body in 3 patients (8% of cases), as well as a highly differentiated neuroendocrine tumor of the stomach body (G1) in 1 patient (2.7% of cases). Conclusion. Histological examination of the fundal part of the stomach typically shows signs of glandular atrophy, widespread pseudopiloric and/or IM, as well as signs of hyperplasia of enterochromaffin-like cells. Reactive changes in the mucous membrane may also be noted in the antral part of the stomach.