CD4 and gastritis: In this model, the transgenic CD4+ T cells initiate disease progression which follows the same pattern seen in humans: gastritis progressing to atrophic gastritis by 2 months of age, metaplasia by 4 months of age, and then mice begin to show signs of gastric dysplasia by 12 months of age (McHugh et al., 2001; Nguyen and Dipaolo, 2013).