Abstract
Solid tumors such as head and neck squamous cell carcinoma (HNSCC) display an intense interaction between tumoral factors and the immune system. Functional modulation of tumor-infiltrating and peripheral blood immune cells plays an important role during tumor progression. In this pilot study we compared biological functions of polymorphonuclear granulocytes (PMN) from the peripheral blood of HNSCC patients and healthy subjects. PMN were simultaneously isolated from the peripheral blood of HNSCC patients and healthy donors for functional analysis (apoptosis, production of reactive oxygen species (ROS), cytokine release and immunophenotyping). PMN from HNSCC patients showed a significantly lower inducible production of ROS (P = 0.02) and reduced spontaneous apoptosis (P = 0.008) compared with PMN from healthy donors. Under standard culture conditions, there was no significant difference regarding the release of inflammatory cytokines between PMN from HNSCC patients and PMN from healthy donors. Confirming previous observations, serum concentrations of PMN-related cytokines were significantly higher in the peripheral blood of HNSCC patients than in that of controls. Importantly, immunophenotyping revealed an increased number of immature PMN in PMN fractions isolated from HNSCC patients. Peripheral blood PMN from HNSCC patients and healthy donors show distinct functional differences. The presence of increased numbers of immature stages of PMN in HNSCC patients may partly contribute to the changes observed. After recruitment to and infiltration of the tumor, PMN may be further modulated in the local tumor microenvironment. This pilot study justifies functional analyses of myeloid cells in larger cohorts of patients with HNSCC.