中文摘要：

目的研究白介素-21（IL-21）在原发性胆汁性肝硬化（PBC）发病机制中的作用。方法收集2010年2月至2011年2月期间长征医院32例首诊PBC患者和26名健康者外周血，采用ELISA检测其外周血IL-21和IL-17水平，以流式细胞术检测外周血辅助性T淋巴细胞17（Th17）和调节性T淋巴细胞（Treg）百分比，以Spearman分析其与血清IL-21水平的关系。以树突状细胞负载丙酮酸脱氢酶复合体E2亚基（PDC—E2）多肽，与初始辅助性T淋巴细胞共培养，以在体外培养和诱导PDC-E2反应性Th17和Treg细胞。在该培养体系中分别加入终浓度为20ng／L的IL-21，采用流式细胞术检测培养体系中对辅助性T淋巴细胞分化的影响。结果PBC患者与健康人血清IL-21水平分别为569（356—735）和228（134～345）ng／L；IL-17水平分别为18．8（13．1～25．5）和7．3（4．6～9．1）mg／L；外周血Th17细胞百分比分别为3．24％（2．47％～3．97％）和0．90％（0．48％～1．19％）；Treg百分比分别为3．68％（2．28％～4．53％）和7．74％（6．23％～9．55％），差异均有统计学意义（Z值分别为5．25、5．69、6．27和5．22，P均〈0．01）。PBC患者血清IL-21水平与Th17细胞百分比以及血清IL-17均呈正相关（r分别为0．54和0．47，P均〈0．01），与Treg百分比呈负相关（r=-0．62，P〈0．01）。在树突状细胞与初始Th细胞的混合培养体系中，加入外源性IL-21时，Th17和Treg细胞比例分别为（83．8±4．3）％和（3．8±0．7）％，未加时分别为（72．0±6．8）％和（6．2±0．4）％，差异均有统计学意义（Z值分别为2．40和2．62，P均〈0．01）。结论IL-21可能通过调节PDC-E2反应性Th17／Treg平衡而参与了PBC的发病机制。（中华检验医学杂杂，2013，36：222-227）

英文摘要：

Objective To investigate the role of IL-21 in the pathogenesis of primary biliary cirrhosis （PBC）. Methods Serum IL-21 and IL-17 level of 32 PBC patients and 26 healthy individuals who first vistited the Changzheng hospital between February 2010 and February 2011 were determined by ELISA. The percentage of Th17 and Treg were detected by flow cytometry and their associations with serum IL-21 were assessed by Spearman. Dendritic cells loading pyruvate dehydrogenase complex E2 subunit （ PDC- E2） polypeptides were cocultured with initial T helper cells to induce PDC-E2 reactive Th17 and Treg ceils in vitro. Flow cytometry was applied to determine the effect of IL-21 （ at concentration of 20 ng/L） on the differentiation of PDC-E2 reactive T cells. Results The levels of IL-21 in PBC patients and healthy individuals were 569 （ 356-735 ） and 228 （ 134-345 ） ng/L respectively, the levels of IL-17 were 18. 8 （ 13.1-25.5 ） and 7.3 （4. 6-9. 1 ） ng/L. Th17 cell percentages in peripheral blood were 3.24% （2.47% -3.97% ） and 0. 90% （0. 48% -1.19% ）. Treg cell percentages were 3.68% （2. 28%-4. 53% ） and 7.74% （6. 23%-9. 55% ）, the Z values of IL-21 ,IL-17,Th17 and Treg were 5.25, 5.69, 6. 27 and 5.22, （P 〈 0. 01 for both）. The level of serum IL-21 in PBC patients was positively correlated with IL-17 and Th17 cells percentage （correlation coefficient r was 0. 54 and 0.47 respectively, P 〈 0.01 for both）, while negatively correlated with Treg cells percentage （ correlation coefficient r was - 0. 62, P 〈 0. 01 ）. In the co-culture system contain dendritic cells and naive Th cells, the percentage of Th17 ceils and Treg ceils after adding IL- 21 were （83.8 ±4. 3）% and （3.8 ±0. 70）%, respectively. By contrast, Th17 and Treg percentage in IL-21 treated co-culture system were （ 72. 0 ± 6. 8 ） % and （ 6. 2 ± 0. 4 ） %, respectively. The different had statistical significance （Z value were 2. 40 and 2. 62, P 〈 0.01 for both）. Conclusion IL-21 is involve