Circulating CD4+CD25+ regulatory T cells in patients with pancreatic cancer

Regulatory T cells (Treg) can inhibit immune responses mediated by T cells. The aim of this study was to evaluate the prevalence of Treg in peripheral blood mononuclear cells from patients with pancreatic cancers in relation to their clinical outcomes. Among a total of 100 patients with ductal adenocarcinoma of the pancreas, 40 underwent pancreatectomy and 60 had unresectable disease. Their peripheral blood mononuclear cells were evaluated to determine the proportion of CD4CD25 (FoxP3) T cells, as a percentage of the total CD4 cells, by flow cytometric analysis. The percentage of Treg in the patients with pancreatic cancer was significantly lower than that in the healthy volunteers (P = 0.048), and the patients who underwent surgical resection had lower Treg levels than those with unresectable disease (P = 0.040). Patients in the resected group with a higher percentage of Treg survived longer (P = 0.021). Treg in patients who remained disease free at postoperative 12 months significantly decreased compared to that of the postoperative period (P = 0.009). A relative increase in Treg may be related to immunosuppression and tumor progression in patients with pancreatic cancer. The immunological monitoring of Treg may be useful to predict the prognosis for patients with pancreatic cancer.