尿液Fractalkine对移植肾急性排斥反应无创性诊断及

Noninvasive diagnostic and predictive value in renal transplant of urine Fractalkine

目的探讨尿液Fractalkine在移植肾急性排斥反应中的诊断价值，并评估尿液Fractalkine在移植受者免疫状态监测中的作用。方法选择2006年1月至2009年10月在浙江大学医学院附属第一医院接受肾脏移植的患者155例，其中急性排斥反应（AR）患者49例，移植肾功能稳定且术后1～2个月程序活检病理诊断为移植肾状态患者58例，程序活检病理诊断为亚临床排斥反应10例，病理证实的急性肾小管坏死9例以及慢性移植肾肾病29例。同时留取健康对照者晨尿尿标本40份。用酶联免疫吸附试验法测定上述尿液Fractalkine的水平（检测结果均用尿肌酐值校正），比较术后不同时间、不同组别之间Fractalkine水平的差异。结果49例AR患者尿液Fractalkine的水平[（429.1±56.1）ng/mmol肌酐]明显高于肾功能稳定患者[（94.6±8.4）ng/mmol肌酐]和健康对照[（84.5±8.9）ng/mmol肌酐]（均P〈0.05）。AR患者尿液Fractalkine 的水平高于急性肾小管坏死患者[（429.1±56.1）比（133.0±9.8）ng/mmol肌酐]及慢性移植肾肾病患者[（429.1±56.1）比（183.0±18.9）ng/mmol肌酐]（均P〈0.001）。构建尿液Fractalkine诊断AR的ROC曲线，曲线下面积为0.920（95% CI：0.875～0.969，P〈0.001），当尿Fractalkine＝157.5 ng/mmol肌酐时，诊断AR的敏感度和特异度分别达到83.7%和84.5%（P〈0.001）。在术后早期的动态观察中发现，肾功能稳定患者术后尿Fractalkine的平均水平基本都在200 ng/mmol肌酐以下，而AR组患者尿Fractalkine的平均水平通常维持在300 ng/mmol肌酐以上。结论作为无创性检查的手段，尿液Fractalkine在诊断AR中有较好的敏感度和特异度，并且能较早预测移植肾AR的发生。

Objective To investigate the relationship between early-stage renal acute rejection （AR） and the level of Fractalkine in urine, explore the diagnostic and noninvasive monitoring value in early stage after transplantation by measurement of urine Fractalkine. Methods Urine samples were examined from renal transplant patients between January 2006 and October 2009. A total of 155 patients were enrolled, including 49 with biopsy-proved AR, 58 patients with stable renal function and no abnormal histological findings, 10 patients with subclinical rejection in protocol biopsy, 9 patients with biopsy-proven acute tubular necrosis and 29 patients with biopsy-proven chronic allograft nephropathy. Additionally, urine samples were also collected from 40 healthy controls. Fractalkine was measured in urine samples using a commercial human Fractalkine enzyme-linked immunosorbent assay （ELISA） kit. Immunohistochemistry for Fractalkine expression was performed on biopsies from renal transplant patients with AR and non-AR. Results Forty- nine patients with AR excreted urinary Fractalkine at a significantly higher level than levels in patients with stable renal function and healthy controls [ （ 429.1 ± 56. 1 ） vs （ 94. 6 ± 8. 4 ） , （ 84. 5 ± 8.9 ） ng/mmol creatine, both P 〈 0. 001 ]. Patients with AR excreted urinary Fractalkine at a significantly higher level than levels in patients with acute tubular necrosis and chronic allograft nephropathy [ （429. 1 ± 56. 1 ） vs （ 133.0 ±9. 8 ）, （ 183.0 ± 18.9 ） ng/mmol creatine, both P 〈 O. 001 ]. Receiver operating characteristic （ ROC ） curve was constructed to determine the discriminatory power of Fractalkine levels for diagnosis of AR. The area under ROC curve was 0. 920（95% CI：0. 875 - 0. 969,P 〈 0. 001 ）, which showed that Fractalkine was a suitable marker for the diagnosis of AR. At a cut-off point of 157.5 ng/mmol creatinine, the sensitivity was 83.7% and the specificity was 84. 5% （ P 〈 0. 001 ） . The dynamic level of urinary Fractalkine in AR patients within 3 weeks after transplantation fluctuated above 300 ng/mmol creatine, which is remarkably higher than patients with stable renal function （below 200 ng/mmol creatinine ）. Conclusions As a noninvasive monitoring method, Fractalkine in urine may be a new approach for detection of AR as well as useful to predict response to antirejection therapy. It has good sensitivity and specificity. Besides,measurement of Fractalkine in urine is a simple, inexpensive method for the routine clinical monitoring after kidney transplantation.