Epidemiological study of polyomavirus type BK infection in renal transplant recipients——single center and prospective study / 中华器官移植杂志

ABSTRACT

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 immunohistochemistry 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 × 105 copies/mL,[1.78 × 103 ～ 8.54 × 109 copies/mL]),BKV viremia (median 2.70 × 104 copies/mL,[1.95 × 103 ～6.31 × 106 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.