Regarding the significance of Th1, Th17, Th22, and Treg responses and TNF-α cytokine in the context of inflammation and the probable roles in pathogenesis of H. pylori-infection, this research was done to study the role of TNF-α expression in the gastric mucosa of H. pylori-positive patients with PUD and gastritis compared to uninfected patients, and we determined the relation between TNF-α expression and the numeral of Treg, Th1, Th17, and Th22 cells in H. pylori-positive patients with PUD. The gene discussed is TNF; the disease is infection.