初发1型糖尿病患者外周血滤泡辅助性T细胞的变化特点

Changes of follicular helper T cells in peripheral blood of patients with newly-diagnosed type 1 diabetes mellitus

目的观察初发1型糖尿病患者外周血单个核细胞（peripheralbloodmononuclearcell，PBMC）中滤泡辅助性T细胞（follicularhelperTcells，Tfh）的数目和功能的变化，并与B淋巴细胞的变化及自身抗体等临床资料进行相关性分析，探讨Tfh参与1型糖尿病发病的免疫学机制。方法收集18例新诊断的1型糖尿病患者和15名健康对照者外周血全血，分离PBMC后流式细胞仪检测CD4＋ CXCR5＋ ICOS＋Tfh及CD19＋B淋巴细胞比例，观察二者在1型糖尿病患者中的变化趋势：实时荧光定量PCR检测Tfh细胞因子白细胞介素21（IL-21）及人B细胞淋巴瘤因子6（Bcl-6）的mRNA水平；分析Tfh细胞与抗谷氨酸脱羧酶抗体（GADA）滴度的相关性。结果（1）与正常对照组相比，新诊断的1型糖尿病患者外周血中的Tfh细胞比例显著上升[（0．09±0．01对0．20±0．01）％，P〈0．01]，同时伴有B淋巴细胞比例增多[（1．68±0．16对3．40±0．25）％，P〈0．01]；（2）在1型糖尿病患者PBMC中Bcl-6的mRNA表达下调30％（P〈0．01），IL-21的mRNA水平下降35％（P〈0．05）；（3）l型糖尿病患者PBMC中Tfh水平与GADA水平呈显著正相关（r=0．792。P〈0．01）。结论初发1型糖尿病患者外周血Tfh 比例显著增加，伴随B淋巴细胞及GADA滴度的上升，表明Tfh可能参与了1型糖尿病的发病。

Objective To observe the changes in follicular helper T cells （Tfh） in peripheral blood mononuclear cell （PBMC） of newly-diagnosed patients with type 1 diabetes mellitus （T1DM）, to analyze its relationship with B lymphocyte and autoantibodies, and to explore the role played by Tfh cells in the pathogenesis of T1DM. Methods Eighteen patients with newly-diagnosed T1DM and 15 healthy control subjects were enrolled. The percentages of Tfh ceils and B cells in PBMC with respective CD4＋ CXCR5＋ ICOS＋ and CD19 ＋ markers were assessed by flowcytometry. The mRNA expressions of interluekin 21 （ IL-21 ） and Bcl-6 were detected in two groups by reahime PCR, and the association between Tfh and glutamic acid decarboxylase antibody （GADA） was analyzed. Results （ 1 ） The proportions of Tfh [ （0.09±0. 01 vs0. 20 ± 0.01 ） % , P〈0. 01 ] and B lymphocyte [ （ 1.68 ±0.16 vs 3.4±0. 25）%, P〈0. 01 ] in PBMC from T1DM group were significantly higher than those in control group. （2） In comparison with control group, mRNA levels of Bcl-6 and IL-21 in PBMC ofT1DM group were decreased by 30% （ P〈 0.01 ） and 35% （P〈0.05）. （3） A positive correlation between the amount of Tfh cell and the titer of GADA was found （ r = 0. 792, P 〈 0. 01 ）. Conclusion The close relationship of Tfh ceils with clinical and biochemical characteristics in newly-diagnosed patients with T1DM demonstrates an important role which may be played by Tfh cells in the pathogenesis of T1DM.