类风湿关节炎患者外周血NK细胞抑制性受体TIGIT基因的表达及意义

The clinical expression and significance of inhibitory receptor TIGIT gene on peripheral NK cells in rheumatoid arthritis

目的探讨抑制性受体TIGIT基因在类风湿关节炎(RA)患者外周血NK细胞中的表达情况及其临床意义。方法病例对照研究。选择2018年12月至2019年6月江西中医药大学附属医院风湿免疫科58例RA患者作为RA疾病组(其中疾病活动亚组30例,疾病缓解亚组28例),健康对照组(HC)22名。收集受试者的相关临床资料,应用流式细胞术比较两组外周血NK细胞TIGIT基因表达水平,ELISA法检测外周血细胞因子IFN-γ分泌水平,并分析TIGIT基因与疾病活动度及IFN-γ分泌水平的相关性。两组间比较采用t检验或者非参数检验,两变量之间相关性采用Pearson相关分析。结果RA疾病组外周血NK细胞数为(13.88±4.56)×10^7个/L,HC组为(25.69±2.48)×10^7个/L,RA疾病组相较于HC组减少(t=-2.036,P=0.041),外周血NK细胞上TIGIT基因表达的百分率在RA疾病组(39.73±9.37)%与HC组(45.64±9.91)%之间的差异无统计学意义(t=-1.241,P=0.218);但TIGIT基因表达的平均荧光强度(MFI)降低,RA疾病组为(7.21±2.03),HC组为(9.01±3.29),(t=-2.947,P=0.004)。疾病活动亚组TIGIT基因在NK细胞上的MFI为(6.72±2.01),低于疾病缓解亚组(8.75±2.64),(t=-3.316,P=0.002),且疾病活动亚组TIGIT基因在NK细胞上的MFI与DAS28评分呈负相关(r^2=0.6496,P<0.0001)。RA疾病组细胞因子IFN-γ分泌水平为(67.13±14.84)pg/ml,高于HC组(57.21±14.23)pg/ml(t=2.757,P=0.017),且疾病活动亚组细胞因子IFN-γ分泌水平与TIGIT基因在NK细胞上的MFI呈负相关(r2=0.6622,P<0.0001)。RA疾病活动亚组外周血单个核细胞刺激实验结果显示刺激后相较于刺激前细胞因子IFN-γ分泌水平降低(t=11.38,P<0.0001)。结论RA患者外周血NK细胞TIGIT基因表达异常,与疾病的活动性及IFN-γ的分泌水平相关。

ObjectiveTo investigate the expression of inhibitory receptor TIGIT gene in peripheral NK cells of patients with rheumatoid arthritis(RA)and its clinical significance.MethodsA case control study was conducted of 58 RA patients(30 patients with active RA disease,28 patients with remission of RA)and 22 healthy controls(HC)in the department of rheumatology and immunology from Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine during December 2018 to June 2019,the related clinical data were collected.Flow cytometry was used to compare the expression of TIGIT gene on peripheral NK cells.The IFN-γsecretion level of cytokines in peripheral blood was detected by ELISA,and analyzed the correlations between TIGIT gene and disease activity and IFN-γlevel.T-test or non-parametric test was used for comparison between the two groups,and Pearson correlation analysis was used for correlation between the two variables.ResultsCompared with HC group,the number of NK cells in RA disease group was reduced,which was(13.88±4.56)×10^7 cells/L in RA disease group and(25.69±2.48)×10^7 cells/L in HC group(t=-2.036,P=0.041).The percentage of TIGIT gene expression in peripheral blood NK cells was not statistically different between RA disease group(39.73±9.37)%and HC group(45.64±9.91)%(t=-1.241,P=0.218).However,the average fluorescence intensity(MFI)of TIGIT gene expression was decreased,which was(7.21±2.03)in RA group and(9.01±3.29)in HC group(t=-2.947,P=0.004).MFI of TIGIT gene in NK cells of the disease active subgroup was(6.72±2.01),lower than that of the disease remission subgroup(8.75±2.64),(t=-3.316,P=0.002),and MFI of TIGIT gene in NK cells of the disease active subgroup was negatively correlated with DAS28 score(r^2=0.649 6,P<0.000 1).The secretion level of IFN-γcytokine in the RA disease group was(67.13±14.84)pg/ml,higher than that in the HC group(57.21±14.23)pg/ml(t=2.757,P=0.017),and the secretion level of IFN-γcytokine in the disease active subgroup was negatively correlated with the MFI of TIGIT gene on NK cells(r2=0.662 2,P<0.000 1).Experimental results of peripheral blood mononuclear cell stimulation in the RA disease activity subgroup showed that the secretion level of cytokines IFN-γwas reduced after stimulation compared with that before stimulation(t=11.38,P<0.000 1).ConclusionThe abnormal expression of TIGIT gene on peripheral NK cells are observed in patients with RA,which correlate with disease activity and IFN-γsecretion level.