Investigation of Regulatory T Cells in Patients with Non-Small Cell Lung Cancer

Objective To evaluate the prevalence of CD4(superscript +) CD25(superscript high) regulatory T cells (Treg cells) in the peripheral blood mononuclear cells (PBMC) and tumor-infiltrating lymphocytes (TIL) of patients with non-small cell lung cancer (NSCLC) and to investigate immunosuppression to the progression of cancer. Methods Peripheral blood and tumor tissues were collected from 20 patients with NSCLC at the time of surgery. None of the patients received surgery, radiotherapy, chemotherapy, or other medical interventions before this study. Cancer stages of the patients were Ⅰ-Ⅲ A. Venous blood samples were obtained from 20 health donors. PBMC were isolated from blood samples by differential centrifugation over Ficoll-Hypaque. TILs were isolated from tumors by differential centrifugation over Ficoll-Hypaque and Percoll. Percentage of CD4(superscript +) CD25(superscript high) Tr/CD4(superscript +) T in PBMC and TIL was assessed by the flow cytometry. Results The percentage of CD4(superscript +) CD25(superscript high) Tr/CD4(superscript +) T in PBMC [(4.87±1.22)%] of NSCLC patients was significantly higher than that in healthy donors [(2.36±0.72) %] (P＜0.01). The percentage of CD4(superscript +) CD25(superscript high) Tr/CD4(superscript +) T in PBMC [(5.40±1.20)% I of NSCLC patients in stage if-ill A was significantly higher than that in stage Ⅰ [(3.87±0.22) %] (P＜0.01). The percentage of CD4(superscript +) CD25(superscript high) Tr/CD4(superscript +) T in TIL [(8.66±0.76)%] of NSCLC patients in stage if-ill A was significantly higher than that in stage Ⅰ [(7.04±0.80)%] (P＜0.01). Conclusion The prevalence of CD4(superscript +) CD25(superscript high) Treg cells in PBMC and TIL of NSCLC patients was significantly higher than that in healthy donors. These Treg cells may be preventing appropriate antitumor immune responses. The population of CD4(superscript +) CD25(superscript high) Treg cells in PBMC and TILs of NSCLC patients with if-ill A stage was significantly higher than that of NSCLC patients with Ⅰ stage. These Treg cells may facilitate development of tumors.