Abstract: Objective This study was designed to explore the relationship between infiltrated Foxp3+gdT cells and the clinical stage of head and neck tumor. Methods Head and neck tumor biopsies were mechanically minced to get tumor infiltrating lymphocytes (TILs). Peripheral blood mononuclear cells (PBMCs) from the patients were isolated by density gradient centrifugation. TILs and PBMCs were stimulated by immobilized anti-pan-TCRgd in vitro for two to four weeks. Freshly isolated and expanded cells underwent immunofluorescence staining and flowcytometry analysis. Commercial head and neck tumor tissue chips were used for immunohistochemical staining. Results Immunofluorescence staining of TILs freshly isolated from 15 head and neck tumor samples showed the gdT/CD3+T ratio as 0.37%~12.35%, Foxp3+ gdT/gdT ratio as 0.13%~34.38%. Following in vitro expansion, gdT/CD3+T cell ratio increased to 20.38%~82.87%. Expanded cells primarily belonged to the Vd1 subset. Tumor tissue chips were divided into four groups according to the T stage of the clinical TNM staging system. Subsequent immunohistochemical results indicated a correlation between the quantity of Foxp3+gdT cells and tumor TNM stage. Conclusion Our data demonstrate the existence of Foxp3+ gdT cells in the head and neck tumor tissue, and suggest that the quantity of tumor infiltrating gdT regulatory cells might be associated with the prognosis of head and neck tumor.

Key words: Head and neck tumor, gdT cell, Foxp3, TNM stage