ObjectiveTo investigate the proportion of peripheral blood CD4+CD25+ regulatory T cells (Tregs) in patients with pancreatic head carcinoma, the dynamic changes of these cells before and after pancreatoduodenectomy were also analyzed. MethodsThe proportions of peripheral blood CD4+CD25+ Tregs in patients with pancreatic head carcinoma and normal individuals were examined by using flow cytometric analysis. The CD4+/CD8+ ratio was also studied before and after operation. ResultsThe patients with pancreatic head carcinoma showed higher ratio of CD4+CD25+ and CD4+CD25high Tregs compared with normal control before operation (Plt;0.05). However, the percentage of these T cells reduced significantly after pancreatoduodenectomy, which was most obviously on the 3rd day after operation (Plt;0.01, Plt;0.05). After operation, CA199 level began to decrease, which was obvious on the fourteen day after operation. This tendency of CD4+CD25high Tregs changes was similar to that of CA199. The patients showed an decreased ratios of CD4+/CD8+ compared with normal controls, which further declined after operation, and reached the lowest point on the seventh day after operation (Plt;0.05). ConclusionsPancreatoduodenectomy may be helpful for the recovery of antitumor immunity. The perioperative period of patients with pancreatic head carcinoma may be a beneficial windowphase for immune intervention and Tregs may be served as target cells.