CD4+CD25high regulatory cells in peripheral blood of cancer patients.

Aim: Regulatory T cells (Treg) that prevent autoimmune diseases by suppression of self-reactive T cells may also suppress the immune response against cancer. Experimental tumor models in mice revealed that Tregs are potent inhibitors of an antitumor immune response. The purpose of the study was to identify a CD4+ population of regulatory T cells expressing high levels of CD25(CD4+CD25 high) in the peripheral blood of cancer patients and provide the opportunity to determine whether cancer patients exhibit an expanded CD4+CD25high pool.

Methods: The frequency of CD4+CD25high in the peripheral blood of 62 cancer patients and 15 healthy donors was determined by flow cytometry.

Results: Compared with healthy donors, cancer patients have an increasing prevalence of CD4+CD25high T cells in the peripheral blood with characteristics of Tregs, i.e. they are CD45-RA(), CD69(-). Among patients, those with higher percentages of CD4+CD25high T cells had a poor prognosis than did those with lower percentages.

Conclusion: We provide evidence of an increased pool of CD4+CD25high in the peripheral blood of cancer patients, which may be related to immunosuppression and tumor progress in cancer patients. This finding suggests that the use of immunomodulatory therapy to treat cancer patients may be an effective strategy.