Clinical Significance of Peripheral Blood T Lymphocyte Subsets inHelicobacter pylori-Infected Patients

Background . Helicobacter pylori chronically colonizes gastric/duodenal mucosa and induces gastroduodenal disease and vigorous humoral and cellular immune responses. Methods . In order to clarify the immunological changes induced by this infection, we determined the percentage and, as indicated, ratios of the following cells in peripheral blood of 45 H. pylori -infected patients and 21 control subjects: CD4 + T cell, CD8 + T cells, T helper 1 cells (Th1), T helper 2 cells (Th2), CD4 + CD25 + T cells, Foxp3 + regulatory T cells (Tregs), CD4/CD8 ratio, and Th1/Th2 ratio. Results . The percentage of CD8 + T cells was significantly lower in H. pylori -infected patients (mean ± SD; 18.0 ± 7.1%) compared to control subjects (mean ± SD; 23.2 ± 7.8%) ( P < 0.05). The CD4/CD8 ratio was significantly higher in H. pylori -infected patients (mean ± SD; 3.1 ± 2.4) compared to control subjects (mean ± SD; 2.1 ± 1.0) ( P < 0.05). The Th1/Th2 ratio was significantly lower in H. pylori -infected patients (mean ± SD; 10.0 ± 8.5) compared to control subjects (mean ± SD; 14.5 ± 9.0) ( P < 0.05). The percentage of CD4 + CD25 + T cells in H. pylori -infected patients (mean ± SD; 13.2 ± 6.2%) was significantly higher than that in control subjects (mean ± SD; 9.8 ± 3.4%) ( P < 0.05). However, there was no significant difference in Tregs. Conclusion . Tregs did not decrease, but the activation of humoral immunity and Th2 polarization were observed in the peripheral blood of H. pylori -infected patients. In some cases, these changes may induce systemic autoimmune diseases.