Infiltrating CD4/CD8 high T cells shows good prognostic impact in pancreatic cancer

Tumor infiltrating lymphocytes in a certain tumor microenvironment are associated with the prognosis of cancer patients. The function of CD4⁺ and CD8⁺ T cells in the microenvironment of pancreatic cancer remains largely unknown. This study aimed to investigate the prognostic value of both CD4⁺ and CD8⁺ TIL subsets and their combined role in pancreatic cancer. In this study, pancreatic cancer tissues and corresponding adjacent normal tissues were collected from 90 patients. The expression levels of CD4 and CD8⁺ T cells in pancreatic cancer tissues were detected by immunohistochemistry method. The results showed that CD4⁺ iTIL expression was significantly correlated with tumor stage. CD8⁺ iTILs were significantly correlated with lymphatic vessel invasion and tumor stage; CD8⁺ sTILs not only showed correlation with lymphatic vessel invasion and tumor stage, but also had correlation with pathologic differentiation; the survival time of high CD4 expression group was longer compared to the low CD4 expression group. CD4⁺ T cells were capable of killing tumor cells and prolonging the survival time of patients either directly or indirectly. According to Cox regression analysis, it was indicated that pathological differentiation, lymphatic vessel invasion, tumor stage, CD4⁺ and CD8⁺ TILs were the principle risk factors of pancreatic cancer prognosis. Especially multivariate analysis showed that pathological differentiation and the combination of CD4⁺ and CD8⁺ TILs expression were independent predictors of pancreatic cancer survival. Expression levels of CD4⁺ and CD8⁺ TILs in pancreatic cancer may provide promising and useful markers for prognosis of pancreatic cancer.