目的 分析肾移植患者尿液中小圆上皮细胞（small round epithelial cells，SREC）阳性指标与BK病毒尿症的相关性。方法 定期收集2017年1月至2019年10月的152名肾移植患者的尿液标本，检测尿SREC指标以及运用实时荧光定量PCR方法检测尿液标本中BKV-DNA拷贝数，并对检测结果进行分析评价。将BK病毒尿症患者的尿沉淀进行尿沉淀染色液和免疫荧光染色处理。结果 36名（23%）BKV尿症患者发病时间为术后（2.5±0.5）个月，患者尿液标本里发现94%为SREC阳性指标，首次检测SREC阳性指标的中位时间为移植后（1.0±0.5）个月，SREC阳性指标以及SREC持续阳性时间段（the duration of SREC positivity，DSRECP）在BK病毒尿症患者的检测率高于非BK病毒尿症患者（P<0.05）。SREC持续阳性时间段能提前（1.0±0.5）个月预测BK病毒尿症发生，阳性预测值为94.44%，阴性预测值为85.34%。回归模型分析证实SREC阳性指标与阳性持续时间段可预测BK病毒尿症的发生不受干扰因素影响（P<0.05），ROC曲线中SREC阳性持续时间段在诊断BK病毒尿症的曲线下面积（AUC）为89.11%，cut-off值为85天，差异具有统计学意义。结论 肾移植患者尿SREC阳性指标与BK病毒尿症具有显著相关性，可作为临床上早期预测并辅助诊断BK病毒尿症的潜在临床指标。

Objective To analyze the correlation between positive indicators of small round epithelial cells (SREC) in urine and BK viruria in renal transplantation recipients. Method A total of 152 renal transplantation patients' urine samples from Jan 2017 to Oct 2019 were collected routinely. The urine small round epithelial cell indicators were detected, and real-time fluorescent quantitative PCR was used to detect the BKV-DNA test during the time of follow-up. Urine sediment specimens from renal transplant recipients with BK viruria were processed with urine sediment staining and immunofluorescence. Results Thirty-six (23%) patients with BK viruria time of onset was (2.5±0.5) months. 94% of patients' urine samples were positive for SREC. The median time for first detection of SREC positive indicators was (1.0±0.5) months after transplantation. The SREC positive indicators and the duration of SREC positivity (DSRECP) in patients with BK viruria was higher than that in non-BK viruria patients (P<0.05). DSRECP could predict the occurrence of BK viruria (1.0±0.5) months in advance, and the positive prediction value was 94.44%, and the negative predictive value was 85.34%. The immunofluorescence results confirmed that there BK viruria particles were in the cytoplasm of SREC, and the number of SREC was directly proportional to copy number of urine BKV-DNA, and the cell morphogenesis was different with Decoy cells. Regression model analysis confirmed that SREC positive indicators and DSRECP could predict the occurrence of BK viruria(P <0.05) without disruption. The area under the ROC curve (AUC) for the diagnosis of BK viruria for DSRECP in the ROC curve was 89.11%, and the cut-off value was 85 days, which was statistically significant. Conclusion Urine SREC in renal transplant recipients can predict the occurrence of BK viruria, and SREC potentially can be a clinical indicator for early clinical prediction and an aid to BK viruria.