Increased Circulating Th22 and Th17 Cells are Associated with Tumor Progression and Patient Survival in Human Gastric Cancer

Although Th22 and Th17 cells have been reported to play critical roles during autoimmunity and inflammation, information on their role in cancer-immunity is limited. In this study, we investigated clinical relevance of circulating Th22 and Th17 cells in patients with gastric cancer (GC). Using multi-color flow cytometry and PMA stimulation, we determined the levels of Th22, Th17 and Th1 cells in the peripheral blood of 32 GC patients and 19 healthy donors, and evaluated their correlations with tumor stage and overall survival. Compared with healthy donors, the frequencies of circulating CD4⁺IL-22⁺ T cells, CD4⁺IL-17⁺ T cells, Th22 (CD4⁺IL-22⁺IL-17^-INF-γ^?) cells, Th17 (CD4⁺IL-17⁺INF-γ^?) cells were increased in patients with GC, but there was no significant differences in the frequencies of CD4⁺IFN-γ⁺ T cells and Th1 (CD4⁺IL-17^?INF-γ⁺) cells. Th22 cells showed positive correlation with Th17 cells and CD4⁺IL-17⁺ T cells in patients with GC. Furthermore, the frequencies of Th22 and Th17 cells were significantly higher in stage III–IV GC patients versus stage I–II and correlated with patients’ overall survival. These data suggest that circulating Th22 cells as well as Th17 cells are increased in the peripheral blood of GC patients with tumor progression, and that these cells may be promising novel clinical markers for GC.