Effect of Depressive Mood on NK Cells in Patients with Pancreatic Tumor – Pilot Study

Aims: In up to 50% of cases is pancreatic cancer accompanied with depressive symptoms or already developed depression. There is well described connection between pancreatic cancer and qualitative changes in immune system. The purpose of this pilot study was to observe the quantitative changes in levels of NK cells and the state of expression of activation and inhibitory receptors on the surface of NK cells in the peripheral blood of patients with pancreatic tumor.

Study Design: This is prospective analytical study.

Place and Duration of Study: The study was carried out between December 2010 and April 2011 at the University Hospital Hradec Králové, Czech Republic.

Methodology: Twenty-one patients with locally advanced or metastatic adenocarcinoma of the pancreas were divided into two groups based on the presence of depressive symptoms. The control group consisted of healthy volunteers. The presence of depressive symptoms was assessed by the Zung self-rating depression and psychiatric examination. Measurement and analysis of peripheral venous blood was performed by flow cytometry to estimate quantitative changes in NK cells. The statistical significance was considered as p < .05.

Results: There was reduced number of CD56brightCD16- subset (P = .01), decreased levels of NKp46 positive NK cells in patients with pancreatic cancer and depressive symptoms (P = .03), but without statistical significant for patient without depression (P = .054). We found decreased number of NKG2A-positive circulating NK cells in patients without depressive symptoms in comparison to control group (P = .05). No differences in NK cells, its subsets and receptors were observed when comparing each group of patients with each other.

Conclusion: The main immunomodulating factor in the case of NK cells in pancreatic cancer is the tumor itself. This is valid particularly for reduced levels of NK cell activation receptors. The presence of chronic stress or depression plays its role in affecting the number and distribution of NK cells and might play an important role in tumor escape mechanism.