Increased CCR4+ and Decreased Central Memory CD4+ T Lymphocytes in the Background Gastric Mucosa of Patients Developing Gastric Cancer After Helicobacter pylori Eradication: An Exploratory Study

The composition of lymphocytes in the gastric mucosa following the eradication of Helicobacter pylori (H. pylori) in patients with and without gastric cancer has not been compared. This study performed a single spot analysis of gastric mucosal lymphocytes after H. pylori eradication in patients with (n = 13) and without (n = 20) gastric cancer. Our comprehensive analysis of lymphocyte composition in the gastric mucosa revealed that: i) the proportion of CD8(+)/CD3(+) cells was relatively higher in the peri-tumor mucosa than in the background mucosa; ii) the proportion of CCR4(+)/CD3(+) cells was higher, and the ratio of CD62L(+)/CD3(+)CD4(+) cells was relatively lower in the gastric mucosa of cancer patients than in non-cancer patients; and iii) the proportion of CD45RA(−)CD62L(+)/CD3(+)CD4(+) cells, namely, the central memory CD4(+) T-cell fraction, was lower in the gastric mucosa of cancer patients than in non-cancer patients. Although the exact mechanism of the altered proportions of CCR4(+)/CD3(+) and central memory CD4(+) cells in the gastric mucosa of patients with cancer is unknown, focusing on lymphocytes in the gastric mucosa might help improve our understanding of gastric cancer development after H. pylori eradication.