Abstract:

Chen Huiyong, Yang Wenlin, Lin Li, Huang Xinyu, Yin Jiawen, Chen Jiahui Department of Dermatology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China Corresponding author: Yang WL, Email: yangwenlin@21cn.com 【Abstract】 Objective To measure the s of programmed death-1 （PD-1） and programmed death ligand-1 （PD-L1） on peripheral blood T lymphocytes of patients with condyloma acuminatum （CA）, and to investigate their role in cellular immunity in these patients. Methods Peripheral blood samples were obtained from 30 patients with CA（CA group）and 20 healthy human controls （control group）. Flow cytometry was conducted to detect the s of PD-1 and PD-L1 on the surfaces of peripheral blood CD4+ and CD8+ T lymphocytes, and to determine the counts of CD4+ and CD8+ T lymphocytes. Enzyme-linked immunosorbent assay （ELISA） was performed to measure the levels of serum interleukin-2 （IL-2） and interferon-γ （IFN-γ）. Statistical analyses were carried out to compare the above parameters between the two groups, and to assess the relationship of PD-1 and PD-L1 s with the counts of CD4+ and CD8+ T lymphocytes as well as with the serum levels of IL-2 and IFN-γ. Results There was a significant increase in the rates of PD-1 and PD-L1 on CD4+ T lymphocytes （PD-1: 9.48% ± 3.31% vs. 7.12% ± 2.16%, t = 2.81, P < 0.01; PD-L1: 4.40% ± 1.46% vs. 3.26% ± 1.13%, t = 3.16, P < 0.01） and CD8+ T lymphocytes （PD-1:12.52% ± 3.17% vs. 9.95% ± 2.17%, t = 3.16, P < 0.01; PD-L1: 7.07% ± 2.23% vs. 5.39% ± 1.69%, t = 2.88, P < 0.01） in the CA group compared with the control group. Moreover, the CA group showed significantly lower counts of CD4+ T lymphocytes （727.43 ± 138.59/μl vs. 804.25 ± 92.83/μl, t = 2.17, P < 0.05） and CD4/CD8 ratio （1.23±0.35 vs. 1.46±0.34, t = 2.24, P < 0.05） than the control group, while no significant difference was observed in CD8+ T lymphocyte counts between the CA group and control group （613.60±121.60/μl vs. 572.45±103.08/μl, t = 1.24, P > 0.05）. The levels of serum IL-2 and IFN-γ were both lower in the CA group than in the control group（t = 2.12, 2.16, respectively, both P < 0.05）. In the CA group, PD-1 and PD-L1 levels on peripheral blood CD4+ T lymphocytes were both negatively correlated with CD4+ T lymphocyte counts, the CD4/CD8 ratio, as well as IL-2 and IFN-γ serum levels（all P < 0.05）, and those on peripheral blood CD8+ T lymphocytes were also negatively correlated with the CD4/CD8 ratio（all P < 0.05）, but uncorrelated with CD8+ T lymphocyte counts（both P > 0.05）. Conclusion PD-1 was highly expressed on peripheral blood T lymphocytes from patients with CA, which may inhibit T lymphocyte-mediated immune response, decrease CD4+ T lymphocyte counts, the CD4/CD8 ratio as well as IL-2 and IFN-γ serum levels by interacting with its ligand PD-L1 and forming the PD-1/PD-L1 signaling pathway.