ORIGINAL ARTICLE RELATIONSHIPS BETWEEN REGULATORY T CELLS AND CD8+ EFFECTOR POPULATIONS IN PATIENTS WITH SQUAMOUS CELL CARCINOMA OF THE HEAD AND NECK

Abstract: Background. Homeostasis of circulating T cells is regulated in complex ways that have not yet been well defined. The balance between type 1 and type 2 T-cell subsets in cancer patients is thought to modulate antitumor immunity. Meanwhile, CD4+CD25+ regulatory T cells (Treg), which are potent inhibi-tors of antitumor immune responses, also play an invaluable role in maintaining immune homeostasis. Methods. Peripheral blood was obtained from 42 patients with squamous cell carcinoma of the head and neck (SCCHN) and 24 healthy age-selected donors. The percentages of T-cell subsets and their cytokine profiles expressed in response to ex vivo stimulation were studied by multicolor flow cytometry. Results. Although patients with SCCHN had a lower percent-age (p <.05) of circulating CD4+ T cells than healthy donors, CD4+CD25+ regulatory T cells (Treg) were increased in th