肾移植后受者外周血中CD39＋调节性T淋巴细胞的表达及其免疫调节作用

Expression and suppressive function of CD39＋ regulatory T cells in kidney transplant recipients

目的探讨肾移植受者外周血中CD39＋调节性T淋巴细胞（Treg细胞）的表达及其免疫调节作用。方法接受首次肾移植的受者30例，术后28d内14例发生急性排斥反应（AR组），16例未发生急性排斥反应（NR组）。所有受者术后采用他克莫司＋吗替麦考酚酯＋泼尼松的三联免疫抑制方案。以健康志愿者12例为对照组。采集受者和志愿者外周血，经密度离心法分离单个核细胞。采用流式细胞术分选CD4＋CD25反应性T淋巴细胞（Tresp细胞）、CD39Treg细胞和CD39＋Treg细胞。检测CD39＋Treg与CIN＋T淋巴细胞的比值，采用酶联免疫吸附试验法检测CD39＋Treg细胞对Tresp细胞分泌丫干扰素（IFN-7）和白细胞介素17（IL-17）的抑制作用。结果AR组CD39＋Treg细胞与CIN＋T淋巴细胞的比值为（1．1±0．5）％，明显低于对照组的（1．8±0．6）％和NR组的（2．1±0．7）％（P〈0．05）。对照组和NR组CD39＋Treg细胞可显著抑制Tresp细胞分泌IFN-7和IL-17（P〈0．05），CD39-Treg可抑制IFN-γ的分泌（P〈0．05），但对IL-17的分泌无抑制作用。NR组CD39＋Treg可抑制IFN-γ的分泌（P〈0．05），但对IL-17的分泌无抑制作用。结论CD39＋Treg细胞具有重要的免疫调节功能；肾移植后急性排斥反应发生时，外周血CD39＋Treg数量减少，且部分抑制功能受损。

Objective To investigate expression and suppressive function of CD39＋ regulatory T cells （Treg） in kidney transplant recipients. Method Thirty recipients of first kidney transplants were treated with tacrolimus, mycophenolate mofetil and prednisone. Within 28 days post- transplantation, there were 14 patients subject to acute rejection （AR group）, and the rest 16 patients had no episodes of acute rejections （NR group）. Twelve healthy volunteers served as healthy controls （HC group）. We collected peripheral blood from the three groups and separated PBMC by density gradient centrifugation, and sorted Tresp, CD39- Treg and CD39＋ Treg by flow cytometry. We next analyzed the ratio of CD39＋ Treg/CD4＋ T cells. ELISA was used to determine the suppressive ability of CD39- Treg and CD39＋ Treg on secretion of IFN-γ and IL-17 by Tresp. Results The ratio of CD39＋ Treg/CD4＋ T cells in AR group was significantly reduced as compared with HC group and NR group （P〈0. 05）. In HC group and NR group, the secretion of IFN-γ and IL-17 by Tresp was suppressed significantly （P%0. 05） by CD39＋ Treg. CD39-Treg could suppress secretion of IFN-γ but not IL-17 production by Tresp. CD39＋ Treg in AR group AR could suppress the secretion of IFN-γ significantly （P〈0. 01）, but not to IL-17 production. Conclusion CD39＋ Treg have important immunoregulation function. The relative amount of CD39＋ Treg was reduced and their regulatory function was impaired in patients with acute rejection.