肾移植受者BK病毒的感染特点

目的 探讨肾移植受者BK病毒（BKV）的感染特点。 方法 于我院门诊选取肾移植术后48个月内的患者共243例作为试验组，同时选取门诊健康体检者82例作为对照组。采集上述2组的血、尿标本，行BKV尿沉渣细胞学计数与实时荧光定量PCR检测。 结果 试验组受者的尿Decoy细胞、BKV尿症与BKV血症的阳性率分别为35.4 %、36.6%和16.9%；对照组分别为4.9%、20.7%和2.9%。试验组受者的尿Decoy 细胞阳性者Decoy细胞中位数水平为6个/10 HPF，BKV DNA阳性者尿液和外周血BKV中位数水平分别为1.50×104拷贝/ml和6.87×103拷贝/ml；对照组分别为2个/10 HPF，1.10×104拷贝/ ml和2.24×103拷贝/ml。与健康者相比，肾移植术后试验组BKV DNA阳性率及水平明显升高（P < 0.01）。肾移植受者的尿液Decoy 细胞计数与尿液BKV含量呈正相关（r = 0.636，P < 0.01）；尿Decoy大量组（＞10个/10 HPF）的血BKV DNA阳性率及水平显著高于少量组（1～5个/10 HPF）（P < 0.05）。 结论　肾移植受者较健康人群易发生BKV再活化。定量尿沉渣细胞学检测简单、易行、敏感，可以作为BKV活化的指标，预测病毒尿症及病毒血症。此外，也可检测血、尿BKV DNA，以了解病毒活化情况和筛查BKV相关的移植肾肾病。

Characteristics of BK virus infection in renal transplant recipients

Objective To investigate the characteristics of BK virus (BKV) infection in renal transplant recipients. Methods A total of 243 renal recipients from our clinic within 48 months after transplantation were enrolled as the trial group and 82 healthy people as the control group. Urine and peripheral blood samples of these two groups were harvested for urinary sediment BKV cytology by Decoy cell counting and BKV DNA by real-time PCR. Results The positive rates of urinary Decoy cell, BKV viruria and viremia were 35.4%, 36.6% and 16.9% in trial group, and 4.9 %, 20.7% and 2.9% in control group, respectively. In trial group, the medians of urinary Decoy cell, urinary BKV and peripheral blood BKV were 6/10 HPF, 1.50×104 copy/ml and 6.87×103 copy/ml respectively, while in control group, they were 2/10 HPF, 1.10×104 copy/ml and 2.24×103 copy/ml. Compared with the healthy people, the positive rates and the levels of BKV DNA in urine and peripheral blood of recipients were significantly higher. The amount of urinary Decoy cells was positively correlated to urinary BKV load(r=0.636, P<0.01). Conclusions BKV replication is easier to happen in renal recipients as compared to healthy people. Counting of urinary Decoy cells is convenient, useful and sensitive to evaluate BK viruria and viremia in renal transplant recipients. BKV DNA detection in urine and peripheral blood can be used to screen the evidence of BK reaction in order to prevent irreversible graft damage by BKV.