To investigate the phenotype, function and correlation with clinical stage of CD4⁺PD-1⁺T cells (programmed cell death receptor 1) in peripheral blood of patients with gastric cancer.

70 patients with gastric cancer treated in Changshu Medical Laboratory from January 2019 to December 2020 were selected as the observation group, and 50 healthy people were selected as the control group. The levels of CD4⁺PD-1⁺T cells in the two groups were compared. The phenotypes of CD4⁺PD-1⁺T cells and CD4⁺PD-1^-T cells in patients with gastric cancer were analyzed. The levels of interferon-γ and tumor necrosis factor-αin CD4⁺PD-1⁺T cells were compared. The correlation between CD4⁺PD-1⁺T cells and disease progression in gastric cancer patients were investigated.

The proportion of CD4⁺PD-1⁺ cells in the observation group was higher than that in the control group (χ²=14.386, P＜0.05); compared with CD4⁺PD-1^-T cells, the ratio of CD45RA⁺CD27⁺ and CD45RA⁺CD27^- cells in CD4⁺PD-1⁺T cells was decreased (P＜0.05), and the ratio of CD45RA^-CD27⁺ cells was increased (P＜0.05); the levels of interferon-γ and tumor necrosis factor-α expressed by CD4⁺PD-1⁺ T cells were lower than those in CD4⁺PD-1^-T cells (P＜0.05); the levels of CD4⁺PD-1⁺T cells were not significantly different between genders and ages (P＞0.05). The proportion of CD4⁺PD-1⁺T cells in patients with advanced gastric cancer was higher than that in patients with early stage (P＜0.05).

The phenotype and function of CD4⁺PD-1⁺T cells in peripheral blood of patients with gastric cancer are significantly changed, and are closely related to the progress of the disease, regardless with age or gender.