Suppressive effects of gemcitabine plus cisplatin chemotherapy on regulatory T cells in nonsmall-cell lung cancer

Objective: To investigate the effect of gemcitabine plus cisplatin chemotherapy on the percentage of CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) regulatory T cells (Tregs) in the peripheral blood of patients with nonsmall-cell lung cancer (NSCLC). Methods: Peripheral blood was taken from patients with NCSLC (before and after chemotherapy) and control subjects with nonmalignant disease. The percentages of CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) Tregs were analysed using flow cytometry. Results: Patients (n = 40) had significantly higher CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) percentages than control subjects (n = 24). CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) percentages increased with tumour progression, fell significantly after chemotherapy, but remained significantly higher than control values. Conclusions: CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) Treg percentages were higher in patients with NSCLC than control subjects, and increased in line with tumour progression. Percentages of CD4(+)CD25(+)FOXP3(+) and CD8(+)CD28(-) Tregs were significantly reduced following gemcitabine plus cisplatin chemotherapy.