Helicobacter pylori (H. pylori) infection involves multiple factors internal and external to the host. Among the internal factors, the immune response plays a fundamental role in the process of antigen presentation, lymphocytic response and cytokine-mediated regulatory response that are directly as sociated with disease progression and prognosis.To compare the immune response in gas tric mucosa of H. pylori infected patients in two regions comparing the risk of developing gastric can cer.71 participants with symptoms of dyspepsia were included. The samples for biopsies were collected from different regions of the gastric mucosa; the identification of H. pylori was carried out by culture and polymerase chain reaction (PCR) of the ureA gene. For the characteri zation of the histopathological alterations and the immunophenotyping of lymphocytes, anti-human mouse monoclonal antibodies specific for each antigen were used: T lymphocytes: CD3 and CD8; B lymphocytes: CD20; Natural Killer Cells: CD56; Macrophages: CD68.The prevalence of H. pylori was 83.1%, the predominant types of gastritis were chronic gastritis and multifocal atrophic gastritis with intestinal metaplasia (63.4% and 22.5%, respectively). The cellular response was charac terized mainly by polymorphonuclear lymphocytes and positive anti-CD8 reactivity both in stroma and epithelium.Multifocal atrophic gastritis was more prevalent in the high-risk region for gastric cancer (GC) while non-atrophic gastritis and the expression of CD3 and CD8 antigens in the foveolar epithelium was higher in the low-risk region.