The Variation of Expression of CD4+ CD25+ Foxp3+ Regulatory T Cells in Patients with Helicobacter Pylori Infection and Eradication

Background/Aims: H.pylori persists for the virtual life of its host. Recent studies suggested that CD4(+) CD25(+) regulatory T cells may be involved in this process. However, the alteration of CD4(+) CD25(+) regulatory T cells after eradication of H.pylori remains a question. Methodology: By using biopsies from 45 H.pylori-positive patients and the ones after eradication of H. pylori and 35 H.pylori-negative adults, real-time PCR and general PCR were used to quantify the expression of Foxp3 mRNA. IHC was used to semi- quantify the number of CD4(+) CD25(+) T cells in gastric mucosa. Results: We found that proportion of CD25(+) T cell in CD4(+) T cells accounted for 0.739% in H. pylori-negative individuals, while it was accounted for 5.012% in H. pylori-positive patients. After eradication of H. pylori, proportion of CD25(+) T cell in CD4(+) cells declined (p<0.01) and it accounted for 0.551%. The level of Foxp3 mRNA significantly decreased (p<0.01) in gastric mucosa of patients after eradication of H. pylori. Conclusions: CD4(+) CD25(+) regulatory T cells decreased in gastric mucosa when patients received eradication of H.pylori. Eradication of H.pylori results in the significant descrease of Foxp3 mRNA in gastric mucosal, or using the drugs of anti-H.pylori induce the reduction of gastric mucosal Foxp3 mRNA expression, which is the a key regulatory gene for the development and function of CD4(+) CD25(+) regulatory T cells, thus contributing to the eradication of H.pylori. All the data offer new possibilities that Foxp3 gene may be the new target of immunization intervention strategies for eradication of H.pylori.