原发性干燥综合征CD4^(+)T细胞维生素D受体表达与疾病活动的相关性

The correlation between the expression of vitamin D receptor in CD4^(+)T cells and the disease activity in primary Sjögren's syndrome

目的探讨原发性干燥综合征(primary Sjogren’s syndrome,pSS)患者CD4^(+)T细胞维生素D受体(vitamin D receptor,VDR)表达,分析VDR表达与疾病活动指标、细胞凋亡的相关性。方法选取2018年1月在南京大学医学院附属鼓楼医院就诊的35例pSS患者作为pSS组,同期取本院体检中健康志愿者50例作为对照组。采用电化学发光法测量25-(OH)-维生素D的浓度,流式细胞术检测CD4^(+)T细胞VDR的表达和细胞凋亡。结果 pSS组和对照组血清维生素D水平(血清25-OH-维生素D含量)差异无统计学意义(P>0.05)。与对照组相比,pSS患者CD4^(+)T细胞占外周血单个核细胞(peripheral blood mononuclear cell,PBMC)百分比、CD4+T细胞VDR表达频率和VDR平均荧光强度(mean fluorescence intensity,MFI)显著增加,组间差异均具有统计学意义{23.90[19.58,29.10]比32.40[24.40,41.30],6.49[3.70,11.83]比22.0[12.90,39.70],789.50[757.00,835.00]比830.00[782.00,982.00],Z=-3.872、-5.933、-3.041,P值均<0.05}。VDR在CD4^(+)T细胞的表达频率与欧洲抗风湿联盟(European League Against Rheumatism,EULAR)干燥综合征疾病活动度指数(EULAR Sjogren’s syndrome disease activity index,ESSDAI)、C反应蛋白(C-reactive protein,CRP)呈显著正相关,与血清补体C4含量呈显著负相关(r=0.360、0.407、-0.492,P值均<0.05),但与红细胞沉降率(erythrocyte sedimentation rate,ESR)、血清球蛋白、免疫球蛋白(immunoglobulin,Ig)G、C3无显著相关性(P值均>0.05)。CD4^(+)T细胞VDR的MFI与CRP、IgG呈显著正相关,与血清C4含量呈负显著相关(r=0.405、0.491、-0.449,P值均<0.05),与ESSDAI、ESR、血清球蛋白或C3无显著相关性(P>0.05)。pSS患者CD4^(+)T细胞凋亡的百分比较对照组显著增加{24.30[18.90,35.20]比10.70[6.64,16.30],Z=-6.923,P<0.001}。VDR在CD4^(+)T细胞的表达频率与CD4^(+)T细胞凋亡率呈显著正相关(r=0.264,P<0.05)。结论 pSS患者CD4^(+)T细胞VDR表达增加,与pSS疾病活动指标、细胞凋亡正相关。VDR上调和T细胞活化有关,可能成为评估pSS疾病活动的新指标。

Objective To explore the expression status of vitamin D receptor(VDR)in CD4^(+)T cells and analyze the correlation between VDR expression and disease activity indicators,cell apoptosis in primary Sjögren’s syndrome(pSS).Methods Thirty-five pSS patients who visited the Affiliated Drum Tower Hospital of Nanjing University Medical School in January 2018 were selected as pSS group,and 50 healthy volunteers from the hospital's physical examination during the same period were selected as control group.The concentration of 25-(OH)-vitamin D was measured by electrochemiluminescence,and the expression of VDR in CD4^(+)T cells and cell apoptosis were determined by flow cytometry.Results There was no statistically significant difference in serum vitamin D levels(serum 25-(OH)-vitamin D content)between the PSS group and the control group(P>0.05).Compared with the control group,the percentage of CD4^(+)T cells in peripheral blood mononuclear cell(PBMC),the frequency of VDR expression and the VDR median fluorescence index(MFI)in CD4^(+)T cells were significantly increased in pSS group{23.90[19.58,29.10]vs 32.40[24.40,41.30],6.49[3.70,11.83]vs 22.0[12.90,39.70],8789.50[757.00,835.00]vs 30.00[782.00,982.00],Z=-3.872、-5.933、-3.041,all P values<0.05).The expression frequency of VDR in CD4^(+)T cells was positively associated with European League Against Rheumatism(EULAR)Sjögren's syndrome disease activity index(ESSDAI),C-reactive protein(CRP),and negatively correlated with serum complement C4 content(r=0.360,0.407,-0.492,all P values<0.05).However,there was no significant correlation with erythrocyte sedimentation rate(ESR),serum globulin,immunoglobulin(Ig)G,and C3(P>0.05).The MFI of VDR in CD4^(+)T cells was positively associated with CRP,IgG,and negatively correlated with serum C4 content(r=0.405,0.491,-0.449,all P values<0.05),but no significant correlation with ESSDAI,ESR,serum globulin and C3(P>0.05).The apoptosis of CD4^(+)T cells was significantly increased in pSS patients compared to the control group{24.30[18.90,35.20]vs 10.70[6.64,16.30],Z=-6.923,P<0.001).The expression frequency of VDR in CD4^(+)T cells was positively correlated with the apoptosis rate of CD4^(+)T cells(r=0.264,P<0.05).Conclusion Increased VDR expression in CD4^(+)T cells was positively associated with disease activity and cell apoptosis in pSS patients.VDR upregulation,as the result of T cell activity,might potentially serve as a biomarker for pSS activity.