Effects of modified FOLFOX-6 chemotherapy on cellular immune function in patients with gastric cancer

Tumor immunosuppression serves an important role in the occurrence and development of gastric cancer. However, the effect of chemotherapy on the immune function of patients remains unclear. The present study aimed to investigate changes in cellular immune function and regulatory T cells (T_regs) in patients with gastric cancer prior to and following chemotherapy. In the peripheral blood of patients with gastric cancer, the percentage of CD4⁺ T cells was substantially decreased compared with that of healthy controls (11.39±5.91 vs. 22.34±3.37%, respectively; P<0.05). High frequencies of CD8⁺ T cells and T_regs were also observed in the peripheral blood of patients. Although the number of T cells decreased following chemotherapy (the proportions of CD4⁺ and CD8⁺ cells were 8.99±7.31 and 16.00±4.51%, respectively), the ratio of CD4⁺/CD8⁺ T cells increased (0.31±0.17 vs. 0.56±0.22; P<0.05). Furthermore, the level of C-C motif chemokine ligand 20 (CCL20) was increased in patients prior to chemotherapy compared with healthy controls. As the sole receptor for CCL20, a high level of expression of C-C motif chemokine receptor 6 on circulating T_regs was also identified in the patients, which decreased following chemotherapy. These results suggest that chemotherapy may efficiently promote cellular immune function and inhibit immunosuppression in patients with gastric cancer.