Alteration of CD4 T cell subsets in metastatic lymph nodes of human gastric cancer.

Studies of tumor-infiltrating immune cells have revealed that immune escape plays an important role in tumor growth. The aim of the present study was to investigate the impact of metastasis affecting CD4+ T cell subsets in human clinical samples. Single-cell suspensions derived from tumor-draining lymph node (TDLN) and primary cancer specimens were assessed by flow cytometry, qRT-PCR and immunohistochemistry. In the CD4+ T cell subsets detected in TDLN, effector T cells (TE) in metastatic TDLN (mTDLN) was significantly lower than that in metastatic-free TDLN (mfTDLN). TE in mfTDLN were increased compared with normal controls. Similarly, effector memory T cells (TEM) in mTDLN was significantly lower than in control and mfTDLN. There was a significantly positive correlation between the proportion of TEM in TDLN and number of tumor-infiltrating CD4+ and CD8+ T cells. Th1 to Th2 ratio was lower in mTDLN, and Treg in mTDLN was significantly higher than in mfTDLN. CD4+ T cell and TE subsets in TDLN were significantly affected by metastasis. Immunosuppressive cells exhibit increased migration to TDLN, in which a subset of CD4+ TE is skewed towards immune tolerance in the tumor microenvironment.