中文摘要：

目的：检测免疫性血小板减少症（ITP）患者中B细胞活化因子（BAFF）、BAFF受体（BAFF-R）及白细胞介素-21（IL-21）的表达,并进行相关性分析,进一步探讨其临床意义。方法：应用酶联免疫吸附试验（ELISA）法检测18例ITP患者和15例对照者血浆BAFF和IL-21的表达;应用流式细胞术检测CD19^＋细胞上BAFF-R的表达及CD3^＋CD8^-IL-21^＋和CD3^＋CD8^＋IL-21^＋细胞的比例。结果：活动性ITP患者血浆BAFF和IL-21水平均明显高于对照者[（589.9±201.9）pg/ml∶（424.5±164.2）pg/ml,（156.8±112.0）pg/ml∶（82.0±27.0）pg/ml,均P〈0.05]。CD19^＋细胞均表达BAFF-R,且ITP患者中BAFF-R表达明显低于对照者[（45.1±10.4）∶（71.2±18.8）,P〈0.01]。发现IL-21表达于CD3^＋CD8-细胞和CD3^＋CD8^＋细胞上,ITP患者中CD3^＋CD8^-IL-21^＋细胞亚群比例、CD3^＋CD8^＋IL-21^＋细胞亚群比例均显著高于对照者[（4.3±1.0）%∶（2.9±1.4）%,（1.0±0.6）%∶（0.6±0.3）%,均P〈0.05]。血浆BAFF与IL-21存在正相关（P〈0.01）,BAFF-R与IL-21存在负相关（P〈0.05）。结论：ITP患者中BAFF、IL-21表达均升高,且两者血浆水平之间存在正相关,BAFF-R与IL-21存在负相关,提示BAFF/BAFF-R信号通路与IL-21在ITP的发病中发挥重要作用。

英文摘要：

Objective：To investigate the expression and correlation of B cell activating factor（BAFF）,BAFF receptor（BAFF-R）and interleukin-21（IL-21）in immune thrombocytopenia（ITP）patients.Method：The expression of plasma BAFF and IL-21were measured by ELISA,the levels of CD3^＋CD8^-IL-21^＋,CD3^＋CD8^＋IL-21^＋ cells and BAFF-R in peripheral blood in ITP patients and controls were measured by flow cytometry.Result：Plasma BAFF and IL-21levels significantly elevated in ITP patients.BAFF-R expressed on all CD19^＋B lymphocytes by flow cytometry and BAFF-R mean fluorescence intensity on CD19^＋B lymphocytes decreased in ITP patients. The percentage of CD3^＋CD8^-IL-21^＋T cells and CD3^＋CD8^＋IL-21^＋T cells significantly increased in ITP patients compared to controls.More importantly,positive correlation between plasma BAFF and IL-21and negative correlation between BAFF-R and IL-21were found in ITP patients.Conclusion：Abnormal expression of BAFF/ BAFF-R and IL-21,and their correlation indicates possible collaborative role in the pathogenesis of ITP.