Immunological features of circulating monocyte subsets in patients with squamous cell carcinoma of the head and neck.

Abstract Background Circulating monocytes are classified into three subsets according to their CD14 and CD16 expressions. Here we investigated all three subsets in patients with squamous cell carcinoma of the head and neck (SCCHN). Methods Peripheral blood from 54 patients with SCCHN and 24 healthy donors (HDs) was tested for flowcytometry. Immunohistochemical staining of the primary tumor was performed. SCCHN cells were co-cultured with human monocytes in vitro. Results The level of intermediate monocytes was significantly lower in SCCHN than in HDs. The expression levels of HLA-G, PD-L1, and CD51 on intermediate monocytes was evidently greater in patients with SCCHN. In vitro co-culturing of SCCHN cells with monocytes revealed a significant increase in CD51 expression levels on monocytes. The decrease in expression levels of the maturation markers CX3CR1 and CD68 was significantly correlated to poor clinical outcomes. Conclusion The level of intermediate monocytes was decreased in cancer patients in favor of immature and expressed immunosuppressive molecules.