Thakur R, Joshi K, Minz M, Singla A, Nada R, Arora S, Jha V, Sakhuja V
Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
Transplant Proc. 2012 Apr;44(3):717-20. doi: 10.1016/j.transproceed.2011.11.054.
BK nephropathy (BKN) is an important complication of renal transplantation, with a reported incidence between 1% and 10% in different parts of the world. Known risk factors for the development of BKN are the recently introduced immunosuppressants and steroids. However, the preexisting viral load may add to the risk for development of BKN. Therefore, the present study was designed to monitor the baseline BK virus (BKV) DNA in renal transplant donors and recipients in India for correlation with the development of BKN.
This study used real-time polymerase chain reaction (PCR) for quantification of BKV DNA in the plasma of kidney transplant donors (n = 38) and recipients (n = 87) at the time of surgery. The control BKV DNA was manufactured from a known positive human sample, by cloning a 133-bp PCR product of bases 4,329 to 4,462 of the large T-antigen (TAg) of BKV in a plasmid vector.
Twenty-five of 87 recipient (28.7%) and 17/38 donor (44.7%) plasma samples were positive for BKV DNA at the time of transplantation with a median viral load of 910 (range 49-4770) and 312 (range 79-1508) copies per mL plasma, respectively. Six of 38 donor-recipient pairs showed viremia in both the recipient and donor: 1 developed histologically proven BKN at 18 months, 1 showed positive immunohistochemistry for SV40 TAg, and 2 others had high levels of viremia (14,545 copies at 6 and 2,617,524 copies at 3 months). None of the other 81 recipients showed evidence of BKN in the follow-up period.
This study showed that 28% of recipients and 44% of donors displayed baseline positivity for BKV DNA in plasma, which is higher than the reported incidence in the West. The baseline levels of BKV DNA in recipients with end-stage renal disease were higher than in donors. Dual positivity for BKV DNA in the plasma of donor-recipient pairs conferred a high risk of development of BK nephropathy in the allografted kidney.
BK肾病（BKN）是肾移植的一种重要并发症，在世界不同地区报道的发病率在1%至10%之间。已知BKN发生的风险因素是最近引入的免疫抑制剂和类固醇。然而，既往病毒载量可能会增加BKN发生的风险。因此，本研究旨在监测印度肾移植供体和受体的基线BK病毒（BKV）DNA，以与BKN的发生进行相关性分析。
本研究采用实时聚合酶链反应（PCR）对肾移植供体（n = 38）和受体（n = 87）手术时血浆中的BKV DNA进行定量。对照BKV DNA由已知阳性人类样本制备，通过将BKV大T抗原（TAg）第4329至4462位碱基的133 bp PCR产物克隆到质粒载体中获得。
87例受体中有25例（28.7%）、38例供体中有17例（44.7%）血浆样本在移植时BKV DNA呈阳性，病毒载量中位数分别为每毫升血浆910份（范围49 - 4770）和312份（范围79 - 1508）。38对供体 - 受体中有6对在受体和供体中均出现病毒血症：1例在18个月时经组织学证实发生BKN，1例SV40 TAg免疫组化呈阳性，另外2例病毒血症水平较高（6个月时为14545份，3个月时为2617524份）。其他81例受体在随访期间均未显示BKN的证据。
本研究表明，28%的受体和44%的供体血浆中BKV DNA基线呈阳性，高于西方报道的发病率。终末期肾病受体的BKV DNA基线水平高于供体。供体 - 受体血浆中BKV DNA双阳性赋予移植肾发生BK肾病的高风险。
