Prevalence and subtypes of BK virus in pediatric renal transplant recipients in Russia

BKV reactivation is associated with impaired graft function in kidney transplant patients. The objective of our study was to determine the prevalence of BKV infection in consecutive pediatric kidney transplant recipients at our center. Fifty-eight pediatric kidney transplant recipients were studied. The mean age at screening was 9.4 ± 2.8 yr, and samples were obtained at a median of 2.4 ± 1.4 yr after transplantation. BKV-DNA was analyzed in urine and plasma by quantitative PCR. Occurrences of BK-DNAuria and BK-DNAemia did not change in the first two yr after transplantation in children and amounted to 21-23% and 7-8%, respectively (p > 0.05). In the third year, the occurrences of BK-DNAuria and BK-DNAemia increased insignificantly to 27% and 9% in the pediatric patients. We also determined the subtypes and subgroups of BK virus isolated from Russian renal transplant recipients and found that BKV isolates were composed of subtypes Ib-2 and IV/c2. The data we obtained indicate that although only 5% of BKVAN cases occurred between years two and five post-transplantation, it seems necessary to regularly monitor pediatric patients for BKV infection through the third year after transplantation.