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 gamma delta 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(+)TCR gamma delta(+) T cells and CD3(+)V alpha 24J alpha 18(+) iNKT cells were determined by flow cytometry. Immunohistochemistry (IHC) was also used for identifying the TCR gamma delta(+) 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(+)TCR gamma delta(+) 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(+)TCR gamma delta(+) T cell percentage between the NUD and PUD groups. The frequency of TCR gamma delta(+) 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 TCR gamma delta(+) 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 gamma delta T cells may be related to development and progression of gastric cancer.