肾移植后BK病毒感染的流行病学特点——单中心、前瞻性研究

Epidemiological study of polyomavirus type BK infection in renal transplant recipients single center and prospective study

目的研究肾移植术后BK病毒感染的流行病学特征。方法选取2010年2月1日至2011年1月31日接受肾移植并长期随访的116例受者。分别于术后0．5、1、3、6、9、12和15个月，用巴氏染色法检测受者尿沉渣Decoy细胞，采用实时荧光定量聚合酶链反应技术检测尿液和外周血BK病毒DNA的载量，并对部分受者进行移植肾组织穿刺活检，以确诊BK病毒相关性肾病（BKVAN）。结果116例受者中，共发现尿沉渣Decoy细胞阳性受者62例，发生率为53．5％；52例受者尿BK病毒DNA阳性，发生率为44．8％；24例受者血BK病毒DNA阳性，发生率为20．7％；4例受者经移植。肾组织活检证实为BKVAN，发生率为3．45％。术后3～9个月是BK病毒感染的高峰时间段，且术后尿和血BK病毒DNA载量的变化趋势基本一致。结论肾移植后3～9个月是BK病毒感染的高发时段，需密切监测受者尿沉渣Decoy细胞及尿和血液中BK病毒DNA载量的变化，及时对BK病毒血症受者进行临床干预，可减少进展为BKAVN的概率。

Objective To investigate the epidemiological characteristics of polyomavirus type BK infection in renal transplant recipients. Method We systematically screened for active BKV infection preoperation and at 0. 5, 1, 3, 6, 9, 12 and 15 months after transplantation in 116 renal transplant recipients. The screening tests included urine cytology （by the Papanicolaou method） and BKV DNA PCR （the kit for testing the BK virus） assay of both urine and plasma, and the results were recorded. Renal biopsy was performed if the graft function was deteriorated gradually or the loads of BKV replication were very high. Routine histopathological examination and immunohistoehemistry were performed on renal tissues from partial patients who received the tests of renal biopsy. Result Throughout the follow-up of 15 months, urinary decoy cells （median 8/10 HPF, [-1-48/10 HPF]）, BKV viruria （median 2.63 × 10^5 eopies/mL, [,1.78 × 10^3 - 8.54 × 10^9 copies/mL]）, BKV viremia （median 2. 70 × 10^4 copies/mL, ]-1.95 × 10^3 -6. 31 × 10^6 copies/mL]）, and BKVAN （4 patients） occurred in 53.46%, 24. 17%, 20. 72% and 3. 45% of renal-transplant recipients, respectively. The positive rate of the decoy cell and BKV DNA in urine reached the peak at the third month to the ninth month after transplantation, and the peak time of the BK viremia was the fifth month post-transplantation throughout the follow-up period. The change in BKV DNA level remained constant in blood and urine throughout the follow-up period. Conclusion The peak time of BKV infection was apparently three to nine months after transplantation, suggesting the importance of monitoring urine cytology and BKV DNA loads in post-transplantation patients closely during this period in order to reduce BKVAN after transplantation.