Expression and clinical significance of programmed death-1 on lymphocytes and programmed death ligand-1 on monocytes in the peripheral blood of patients with cervical cancer

The programmed death-1 (PD-1) signaling pathway serves a critical role in immune regulation and tolerance by suppressing the activation and proliferation of T cells. The aim of the present study was to investigate the effect of PD-1 and programmed death-ligand 1 (PD-L1) on the development of cervical carcinoma and cervical intraepithelial neoplasia (CIN). A total of 40 healthy controls (HC), 40 patients with CIN and 66 newly diagnosed cervical cancer patients were recruited. The expression level of PD-1 expression on peripheral cluster of differentiation (CD)4+ and CD8+ T cells and PD-L1 on monocytes was analyzed by flow cytometry. The expression level of soluble PD-L1 in serum was determined by an ELISA. The results of the present study demonstrated that the PD-1 expression level on CD4+ and CD8+ T cells was significantly increased in CIN and cervical cancer, compared with that in HC. In addition, the PD-1 expression level on CD4+ and CD8+ T cells was increased in cervical cancer, compared with that in CIN. However, the expression level of PDL-1 on CD14+ monocytes was increased in cancer and CIN, but limited in cancer and CIN. In addition, PD-1 expression on CD4+ T cells was positively associated with PD-1 expression on CD8+ T cells in cervical cancer (P<0.05). Further analyses revealed that the proportion of PD-1 on CD4+ and CD8+ T cells were positively associated with tumor stages. However, no difference in the degree of soluble PD-1 among cancer, CIN and HC cells was revealed. The results suggested that the PD-1 signaling pathway is involved in the development of CIN and cervical cancer.