CD4+CD25+调节性T细胞、Foxp3 mRNA及可溶性白细胞介素2受体检测在肾移植中的意义

目的 观察肾移植患者外周血中CD4+CD25+调节性T细胞水平及其表面特异性标志物Foxp3和可溶性白细胞介素2受体（sIL-2R）的变化，探讨其在诊断移植肾急性排斥反应中的作用和价值。 方法 选取42例维持性血液透析接受同种异体肾移植治疗的患者及30例健康体检对照者。在患者移植前、移植后1、2、4、8周或发生排斥反应时，以流式细胞仪检测外周血中CD4+CD25+调节性T细胞水平；荧光定量PCR检测Foxp3 mRNA表达；双抗体夹心酶联免疫吸附法（ELISB）检测血浆中sIL-2R水平。 结果 (1)移植后第1、2、4、8周急性排斥反应组CD4+CD25+调节性T细胞、Foxp3 mRNA水平明显低于同期未发生排斥的肾功能稳定组，而sIL-2R水平却显著高于肾功能稳定组。(2)血液透析患者外周血CD4+CD25+调节性T细胞(9.22±3.53)%]、Foxp3 mRNA（0.82±0.36）×10-3]及sIL-2R（856.30±108.24） U/ml]水平与健康对照组分别为(6.09±1.99)%、(0.50±0.28)×10-3、(247.35±11.24) U/ml]比较，差异均有统计学意义(P < 0.01)。(3)肾移植后随着肾功能的恢复，外周血CD4+CD25+调节性T细胞(16.53±4.14)%]、Foxp3 mRNA(4.97±1.94)×10-3]显著升高(P < 0.01)，而sIL-2R（463.72±31.23）U/ml]水平明显降低(P < 0.01)。(4)当发生急性排斥反应时，CD4+CD25+调节性T细胞(12.18±2.86)%]、Foxp3 mRNA(3.15±1.22)×10-3]显著降低(P < 0.01)，而sIL-2R(748.36±115.41) U/ml]水平明显升高(P < 0.01)，并且这些变化早于Scr的变化。(5)患者移植前后外周血CD4+CD25+调节性T细胞百分率与Foxp3 mRNA水平均呈正相关（分别为r ＝ 0.904、0.932，P < 0.01），但与sIL-2R水平无相关。 结论 外周血CD4+CD25+调节性T细胞、Foxp3 mRNA及sIL-2R水平的测定均可以作为肾移植患者移植后发生急性排斥反应的早期预测指标，并可判断预后。

Significance of the detections for CD4 +CD25 + regulatory T cells, Foxp3 mRNA and interleukin 2 receptor in kidney transplantation recipients

Objective To observe the changes of CD4+CD25+ regulatory T cells, Foxp3 mRNA and soluble interlukin 2 receptor (sIL-2R) in the peripheral blood of kidney transplantation recipients and to evaluate their effect on the diagnosis of acute rejection. Methods Forty-two renal transplant recipients and 30 healthy controls were enrolled in this study. CD4+CD25+ regulatory T cells proportion, Foxp3 mRNA and sIL-2R of pre-transplantation and those of day 7,14, 28, 56 of post-transplantation were measured by flow cytometer, fluorescent quantization PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Biochemistry appliance was used to detect serum creatinine. The diagnosis of acute rejection in transplanted kidney was based on the clinical symptoms, the laboratory examinations, Doppler ultrasound and biopsy. Results (1)At day 7, 14, 28, 56 of post-transplantation, CD4+CD25+ regulatory T ceils proportion, Foxp3 mRNA level in acute rejection group were significantly decreased compared with those in non-acute rejection group. (2) There were significant differences of peripheral blood CD4+CD25+ regulatory Tcells(9.22±3.53)% vs (6.09±1.99)%, P<0.01], Foxp3 mRNA(0.82±0.36)×10-3 vs (0.50±0.28)×10-3, P<0.01] and sIL-2R levels (856.30±108,24) U/ml vs (247.35±11.24) U/ml, P<0.01]between patients of pre-transplantation and healthy control group. (3)Plasma CD4+CD25+ regulatory T cells (16.53±4.14)%] and the expression of Foxp3 mRNA (4.97±1.94)×10-3] was significantly increased, but sIL-2R level (463.72±31.23) U/ml] was significantly decreased as the transplanted renal function was restored (all P<0.01). (4) Plasma CD4+CD25+regulatory T cells (12.18~2.86)%] and the expression of Foxp3 mRNA (3.15±1.22)×10-3] was significantly decreased (P<0.01), and sIL-2R level (748.36±115.41) U/ml] was significantly increased (P<0.01) when acute rejection occurred. The above changes had an earlier onset than the change of Scr. (5)The percentage of CD4+CD25+ regulatory T cells was positively correlated with the Foxp3 mRNA level (P<0.01), but was not correlated with sIL-2R level in all the patients. Conclusion The measurement of these markers in peripheral blood may be an important guideline to the diagnosis and prognosis of acute rejection in renal transplant recipients.