DNMT1 and chronic atrophic gastritis: Therefore, we propose that the polymorphisms of DNMT1 may impair the function of the DNMT1 protein, and fail to maintain the silenced state of Th1 signature genes in Th2 cells, skewing T-cell response towards Th1 responses, resulting in clearance of H. pylori infection and causing relative severe gastric atrophy at the same time.