Pinto Gabriel Godinho, Poloni José Antonio Tesser, Paskulin Diego D'Avila, Spuldaro Fabio, Paris Fernanda de, Barth Afonso Luís, Manfro Roberto Ceratti, Keitel Elizete, Pasqualotto Alessandro C
Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre, Brasil.
Santa Casa de Misericórdia de Porto Alegre, Porto Alegre, Brasil.
J Bras Nefrol. 2018 Jan-Mar;40(1):59-65. doi: 10.1590/1678-4685-JBN-3776. Epub 2018 Apr 19.
BK virus (BKV) infection in renal transplant patients may cause kidney allograft dysfunction and graft loss. Accurate determination of BKV viral load is critical to prevent BKV-associated nephropathy (BKVAN) but the cut-off that best predicts BKVAN remains controversial.
To evaluate the performance of a commercial and an in-house qPCR test for quantitative detection of BK virus in kidney transplant recipients.
This was a prospective study with kidney transplant recipients from two large university hospitals in Brazil. Patients were screened for BKV infection every 3 months in the first year post-transplant with a commercial and an in-house real time polymerase chain reaction (qPCR) test. BKVAN was confirmed based on histopathology. The area under the curve for plasma qPCR was determined from receiver operating characteristic analysis.
A total of 200 patients were enrolled. Fifty-eight percent were male, 19.5% had diabetes mellitus, and 82% had the kidney transplanted from a deceased donor. BKV viremia was detected in 32.5% and BKVAN was diagnosed in 8 patients (4%). BKVAN was associated with viremia of 4.1 log copies/mL, using a commercial kit. The cut-off for the in-house assay was 6.1 log copies/mL. The linearity between the commercial kit and the in-house assay was R2=0.83.
Our study shows that marked variability occurs in BKV viral load when different qPCR methodologies are used. The in-house qPCR assay proved clinically useful, a cheaper option in comparison to commercial qPCR kits. There is an urgent need to make BKV standards available to the international community.
肾移植患者感染BK病毒（BKV）可能导致肾移植功能障碍和移植肾丢失。准确测定BKV病毒载量对于预防BKV相关性肾病（BKVAN）至关重要，但最能预测BKVAN的临界值仍存在争议。
评估一种商业qPCR检测方法和一种内部qPCR检测方法对肾移植受者中BK病毒定量检测的性能。
这是一项对来自巴西两家大型大学医院的肾移植受者进行的前瞻性研究。在移植后的第一年，每3个月用一种商业实时聚合酶链反应（qPCR）检测方法和一种内部qPCR检测方法对患者进行BKV感染筛查。BKVAN通过组织病理学确诊。通过受试者操作特征分析确定血浆qPCR的曲线下面积。
共纳入200例患者。58%为男性，19.5%患有糖尿病，82%接受的是来自已故供体的肾脏移植。32.5%的患者检测到BKV病毒血症，8例患者（4%）被诊断为BKVAN。使用商业试剂盒时，BKVAN与病毒血症水平4.1 log拷贝/mL相关。内部检测方法的临界值为6.1 log拷贝/mL。商业试剂盒与内部检测方法之间的线性关系为R2 = 0.83。
我们的研究表明，使用不同的qPCR方法时，BKV病毒载量存在显著差异。内部qPCR检测方法在临床上被证明是有用的，与商业qPCR试剂盒相比是更便宜的选择。迫切需要向国际社会提供BKV标准。
