Effect of surgery on pancreatic tumor-dependent lymphocyte asset: modulation of natural killer cell frequency and cytotoxic function.

Objectives: Tumor burden and invasiveness establish a microenvironment that surgery could alter. This study shows a comprehensive analysis of size, dynamics, and function of peripheral lymphocyte subsets in pancreatic cancer patients before and at different times after duodenopancreatectomy. Methods: Lymphocyte frequency and natural cytotoxicity were evaluated by flow cytometry and in vitro assay on peripheral blood from initial and advanced-stage pancreatic cancer patients before (BS), at day 7 (PS7), and at day 30 (PS30) after surgery. Results: An increase in natural killer (NK) cells and the diminution of B-cells occurred at PS30, whereas cytotoxicity decreased at PS7. The positive correlation between NK frequency and cytotoxicity at BS and PS7 revealed an altered NK behavior. The elevation of NK cell frequency at PS30, an initial defect in CD56bright NK, and the aberrant correlation between NK frequency and cytotoxicity remained significant in advanced-stage patients, whereas the diminution of NK cytotoxicity only affected initial stage patients. Conclusions: The NK cell functional ability is altered in presurgery patients; duodenopancreatectomy is associated with short-term impairment of NK function and with a long-term NK cell augmentation and reversion of the aberrant NK behavior, which may impact on immunosurveillance against residual cancer.