The correlation between the subsets of tumor infiltrating memory T cells and the expression of indoleamine 2,3-dioxygenase in gastric cancer

摘要

Backgrounds: Although many researchers have concentrated on the mechanism of T cell anergy resulting from over-expression of Indoleamine 2,3-dioxygenase (IDO), it remains unclear what alterations will developed in memory T cells (Tm) under over-expression of IDO. Methods: Immunohistochemical staining for IDO expression in gastric cancer tissues (n = 50) was carried out. Tumor-infiltrating memory Tm cells were counted by flow cytometry. The association between IDO expression and the subsets of tumor infiltrating Tm are discussed. Results: The higher IDO expressions were significantly associated with deeper invasion (P = 0.016) and higher frequencies (P = 0.038) of lymph node metastasis. The lower tumor-infiltrating CD4+Tm were significantly associated with the advanced clinical stage (P = 0.026) and lymph node metastasis (P = 0.016). The lower percentages of CD8+Tm were significantly related to undifferentiated histological type (P = 0.042) and lymph node metastasis (P = 0.037). However, the lower percentage of CD8 +Tem was significantly correlated to differentiated histological type (P = 0.017), lower frequencies of lymph node metastasis (P = 0.014), and earlier clinical stage (P = 0.008). The higher IDO expression patients had significantly lower percentages of CD4+Tm (P = 0.012) and CD8 +Tm (P = 0.033). Nevertheless, it was confirmed that the higher level of IDO expression correlated with higher percentages of CD8+Tm cells in univariate and multivariate analysis (P = 0.011). Conclusion: IDO over-expression and Tm in tumor microenvironments were correlated with the disease stage and histological type of gastric cancer. Higher IDO expression was related to the lower percentage of CD4+Tm and CD8+Tm, whereas the higher level of IDO expression related with a higher percentage of CD8+Tem.