Increased levels of immune inhibitory CD34(+) progenitor cells in the peripheral blood of patients with node positive head and neck squamous cell carcinomas and the ability of these CD34(+) cells to differentiate into immunestimulatory dendritic cells

OBJECTIVES: This study determined whether mobilization of immune inhibitory CD34(+) cells by head and neck squamous cell carcinomas (HNSCC) is most pr ominent in patients who are node positive and whether these CD34(+) cells c ould differentiate into immune stimulatory dendritic cells. STUDY DESIGN AND SETTING: Peripheral blood from patients with head and neck cancer was used to measure the frequency of CD34(+) cells and their capaci ty to differentiate into immune stimulatory dendritic cells. RESULTS: This study demonstrated that increased CD34(+) cell levels were mo st prominent in patients who were node positive and patients with recurrent disease. These CD34(+) cells differentiated into dendritic cells that were able to present tetanus toxoid to autologous T-cells. CONCLUSIONS: Immune suppressive CD34(+) cells that are prominent in patient s with HNSCC who are node positive are able to develop into immune stimulat ory dendritic cells. SIGNIFICANCE: Differentiation of tumor-mobilized CD34(+) cells into dendrit ic cells may be an immunotherapeutic approach to stimulate antitumor reacti vity.