Circulating CD8⁺CD122⁺ T cells as a prognostic indicator of pancreatic cancer

Purpose: The distribution of tissue infiltrating lymphocytes has been shown to affect the prognosis of patients with pancreatic cancer in some previous studies. However, the role of peripheral lymphocytes in pancreatic cancer remains debated. The purpose of this study was to analyze the peripheral subtypes of T lymphocytes, and establish their association with the prognosis of patients with pancreatic cancer. Methods: Blood and tissue samples were collected from patients with metastatic pancreatic cancer (n = 54), resectable pancreatic cancer (n = 12), and benign pancreatic cysts (n = 52) between April 2019 and January 2022 and analyzed. Results: Patients with metastatic pancreatic cancer had a larger proportion of both tumor-suppressive and tumor-promoting cells than those with benign pancreatic cysts. In addition, the proportion of peripheral CD4⁺ T cells positively correlated with the survival of patients with metastatic pancreatic cancer, and the proportion of peripheral CD8⁺CD122⁺ T cells was associated with early mortality (< 90 days). After chemotherapy, CD8⁺CD122⁺ T cells decreased in patients who had a partial response or stable disease. Moreover, by analyzing resected specimens, we first proved that the existence of CD8⁺CD122⁺ T cells in a tumor microenvironment (TME) depends on their proportion in peripheral blood. Conclusion: Circulating CD8⁺CD122⁺ T cells can be a prognostic indicator in patients with pancreatic cancer.