Characterization of intracellular cytokine profile of CD4(+) T cells in peripheral blood and tumor-draining lymph nodes of patients with gastrointestinal cancer

Abstract

Background: Analysis of serum cytokine levels has shown that cancer-bearing hosts have lower levels of IL-2 and IFN-γ, suggesting that Th1-type immunity is impaired by cancer. However, the mechanisms of the Th1 dysfunction are not clearly understood. Method: The frequencies of Th1 cells in CD4(+) helper T cells were evaluated with an intra-cytoplasmic cytokine staining method in peripheral blood lymphocytes (PBL) and lymph node lymphocytes (LNL) of patients with gastrointestinal cancer. Results: Activation of lymphocytes with PMA + lonomycin induced the expression of IL-2 and IFN-γ in each lymphocyte population. Compared with PBL of non-malignant donors, PBL in cancer patients contained significantly lower frequencies of CD4(+) T cells that produced IL-2 and IFN-γ. LNL in cancer patients also contained lower levels of IL-2- and IFN-γ-producing CD4(+) T cells, although the percentages did not show significant differences from those of PBL in the same patients. Conclusion: Our data suggest that suppression of Th1 cytokine in cancer patients is, at least in part, due to the decreased frequency of Th1 cells with CD4(+) phenotype.