非小细胞肺癌患者外周血PD-L1蛋白的表达及其对治疗效果的评估作用

Expression of PD-L1 protein in peripheral blood of patients with non-small cell lung cancer and its role in evaluating the therapeutic effect

目的探究非小细胞肺癌(NSCLC)患者血清程序性细胞死亡配体1(PD-L1)蛋白表达及其对治疗效果的评估作用。方法选取32例原发性NSCLC患者作为实验组、32例健康志愿者作为对照组,分别抽取2组受试者治疗前1 d的清晨外周静脉血10 mL,采用免疫磁珠法富集循环肿瘤细胞并进行阳性评估;采用免疫荧光法检测实验组循环肿瘤细胞阳性患者外周血PD-L1蛋白的表达,分析PD-L1蛋白表达与患者临床病理特征的关系;采用酶联免疫吸附法检测实验组循环肿瘤细胞阳性患者血清干扰素-γ(IFN-γ)水平,荧光显微镜下观察并计算群集分化8(CD8)+T细胞比率,分析IFN-γ水平、CD8^(+)T细胞比率与PD-L1表达的关系;评估实验组患者临床疗效和预后,并分析外周血循环肿瘤细胞PD-L1表达与临床疗效及预后的关系。结果实验组患者外周血循环肿瘤细胞检出率明显高于对照组,差异有统计学意义(P<0.01);实验组患者外周血循环肿瘤细胞中PD-L1蛋白表达阳性率为70.00%,且与患者吸烟、TNM分期和远处转移有关(P<0.05);实验组外周血循环肿瘤细胞PD-L1蛋白表达阴性患者血清IFN-γ水平及CD8^(+)T细胞比例高于阳性者(P<0.05),IFN-γ≤29 ng/L和>29 ng/L时与PD-L1蛋白表达分别呈正相关(r=0.658,P<0.05)和负相关(r=-0.476,P<0.05),CD8^(+)T细胞比例≤43%和>43%时与PD-L1蛋白表达分别呈正相关(r=0.733,P<0.05)和负相关(r=-0.357,P<0.05),实验组患者外周血循环肿瘤细胞中PD-L1表达与其临床疗效呈负相关(r=-0.622,P<0.001),实验组患者外周血循环肿瘤细胞中PD-L1表达与其预后呈负相关关系(r=-0.557,P<0.001)。结论NSCLC患者外周血中PD-L1蛋白的表达对评估患者的疾病分期、远处转移、治疗效果及预后有着重要意义。

Objective To investigate the expression of programmed cell death ligand 1(PD-L1)of circulating non-small cell lung cancer(NSCLC)cells and the role of PD-L1 expression in evaluating therapeutic effect.Methods Thirty-two patients with primary NSCLC were selected as the experimental group and 32 healthy volunteers as the control group.Each subject was withdrawn 10 mL of fasting venous blood in early morning on the day before treatment.Circulating NSCLC cells were enriched using immunomagnetic beads(IMB)and then evaluated whether they were NSCLC cells.PD-L1 expression of NSCLC cells was detected by immunofluorescence.The correlation of PD-L1 expression with clinical pathological characteristics was analyzed.Enzyme-linked immunosorbent assay was used to detect serum interferon-γ(IFN-γ)in circulating NSCLC cells-positive patients in the experimental group.The cluster differentiation 8(CD8)+T cells was observed under a fluorescence microscope,and CD8^(+)T cell ratio was calculated.The association of IFN-γlevels,CD8^(+)T cell ratio with PD-L1 expression was analyzed.The clinical efficacy and prognosis of patients in the experimental group were evaluated.The association of PD-L1 expression of circulating NSCLS cells in peripheral blood with the clinical efficacy and prognosis were analyzed.Results The detection rate of NSCLC cells positive patients was higher in experimental group than that in control group(P<0.01).The percentage of circulating NSCLC cells with positive PD-L1 protein in peripheral blood was 70.00%in experimental group.PD-L1 expression was associated with smoking,TNM staging and distant metastasis(P<0.05).In experimental group,serum IFN-γlevels and CD8^(+)ratio were higher in patients with circulating PD-L1-negative NSCLC cells than those in patients with circulating PD-L1-positive NSCLC cells(P<0.05).When IFN-γ≤29 ng/L,IFN-γpositively correlated with PD-L1 expression(r=0.658,P<0.05).When IFN-γ>29 ng/L,IFN-γnegatively correlated with PD-L1 expression(r=-0.476,P<0.05).When CD8^(+)T cell ratio≤43%,CD8^(+)T cell ratio was positively associated with PD-L1 expression(r=0.733,P<0.05).When CD8^(+)T cell ratio>43%,CD8^(+)T cell ratio was negatively associated with PD-L1 expression(r=-0.357,P<0.05).In experimental group,PD-L1 expression of circulating NSCLC cells in peripheral blood was negatively associated with the clinical efficacy(r=-0.622,P<0.001)and prognosis(r=-0.557,P<0.001).Conclusion PD-L1 protein expression of circulating NSCLC cells in peripheral blood is important to evaluate the stage of disease,distant metastasis,therapeutic effect and prognosis of NSCLC patients.