Regulatory T Cells and Myeloid-Derived Suppressor Cells in Patients with Peptic Ulcer and Gastric Cancer.

BACKGROUND: Regulatory T Cells (Tregs) and Myeloid-Derived Suppressor Cells (MDSCs) are two main regulatory cells modulating the immune responses in inflammation and cancer. OBJECTIVE: To investigate and compare Tregs and MDSCs in peptic ulcer and gastric cancer. METHODS: Patients with dyspepsia were selected and divided into three groups of non-ulcer dyspepsia (NUD, n=22), peptic ulcer disease (PUD, n=25), and gastric cancer (GC, n=27) according to their endoscopic and histopathological examinations. Helicobacter pylori infection was diagnosed by rapid urease test and histopathology. The number of peripheral blood CD4+CD25+FoxP3+Tregs and CD14+HLA-DR- MDSCs were determined in all patients, by flow cytometry. The number of FoxP3+ regulatory T cells was also determined by immunohistochemistry (IHC). RESULTS: The percentage of peripheral blood Treg cells in both PUD (0.81 ± 0.39, p<0.001) and GC groups (0.98 ± 0.65, p<0.001) were significantly higher than in NUD group (0.46 ± 0.10). These results were also confirmed by IHC. A significantly higher percentage of MDSCs in patients with PUD (0.73 ± 0.19, p<0.001) and GC (0.73 ± 0.16, p<0.001) was also observed when compared to NUD group (0.46 ± 0.16). There was no difference in the percentages of these two cell types between the PUD and GC groups. The percentages of Tregs and MDSCs in patients with PUD and GC were not significantly correlated. CONCLUSIONS: Both Tregs and MDSCs showed higher frequencies in PUD and GC. These results suggest that immune-modulation by the Tregs and MDSCs may play a role in the pathogenesis of PUD and GC.

Frequency of γδ T Cells and Invariant Natural Killer T Cells in Helicobacter Pylori-infected Patients with Peptic Ulcer and Gastric Cancer.

To clarify the effect of γδ T cells and invariant Natural Killer T (iNKT) cells in pathophysiology of dyspeptic disorders, number of these two cells in patients with non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), and gastric cancer (GC) were compared.Patients with dyspepsia were divided into three groups of NUD, PUD, and GC according to their endoscopic and histopathological examinations. Helicobacter pylori infection was diagnosed by rapid urease test and histopathology. The number of peripheral blood CD3+TCRγδ(+) T cells and CD3+Va24Ja18+ iNKT cells were determined by flow cytometry. Immunohistochemistry (IHC) was also used for identifying the TCRγδ+ cells.Forty two patients with NUD (31.6%), 44 with PUD (33.1%), and 47 with GC (35.3%) were included in the study. The frequency of CD3+TCRγδ(+) T cells in peripheral blood of patients with GC (2.71±0.25) was significantly lower than that in NUD (3.97±0.32, p<0.05) and PUD groups (3.87±0.32, p<0.05). However, there was no significant difference in CD3+TCRγδ(+) T cell percentage between the NUD and PUD groups. The frequency of TCRγδ(+) lymphocytes was significantly lower in tissue samples from patients with GC (4.81±0.53) than in NUD (11.09±1.09, p<0.0001) and PUD groups (11.11±1.01, p<0.0001). Also, we could not find any significant difference in the percentage of mucosal TCRγδ+ cells between the NUD and PUD groups. The results showed no significant difference in iNKT cells percentage among the three groups of patients.The results suggest that decreasing number of γδ T cells may be related to development and progression of gastric cancer.