Objective: To detect the proportion of CD4+ CD25high CCR6+ regulatory T cells in peripheral blood mononuclear cells and tumor infiltration lymphocytes from breast cancer patients and explore its significance.
Methods: Lymphocytes isolated from blood and tumor mass of breast cancer patients were analyzed for the proportion of CD4+ CD25high CCR6+ regulatory T cells by flow cytometry. The expression of Foxp3 on CD4+ CD25high CCR6+ regulatory T cells, as well as CD45RO, CD44 and CD62L, were also analyzed. The effects of CD4+ CD25high CCR6+ regulatory T cells on the proliferation of CD4+ CD25- T cells also were detected by 3H-incorporation assay.
Results: Compared to the control, increased proportion of CD4+ CD25high CCR6+ regulatory T cells was observed in PBMCs and TILs from breast cancer patients. Moreover, CD4+ CD25high CCR6+ regulatory T cells, expressing high level of Foxp3, displayed effector memory phenotype determined by high level expression of CD45RO, CD44 and low level of CD62L. In addition, CD4+ CD25high CCR6+ regulatory T cells could inhibit the proliferation of CD4+ CD25- T cells in vitro.
Conclusion: The enrichment of CD4+ CD25high CCR6+ regulatory T cells in tumor mass in breast cancer patients, which might be close related to long term immunoescape of tumor.