Incidence of BKV in the urine and blood samples of pediatric patients undergoing HSCT.

The aims were to investigate the incidence of BKV infection and the presence of HC in pediatric patients undergoing HSCT. Twenty-four children patients (M/F: 17/7) undergoing HSCT in a single center over a period of 1 year were included in the study. The presence of BKV DNA was determined by quantitative real-time PCR in plasma and urine samples at the following times: before transplantation, twice a week until engraftment time, and weekly for + 100 days. The mean age of the patients was 7.79 ± 5.03 years, the mean follow-up time was 95.6 ± 25.9 days, and the average number of samples per patient was 15.8 ± 3.2. BKV DNA was detected in at least one urine sample in 91.6% (n: 22) and at least one plasma sample in 75% (n:18) of the patients. The median time to the first BKV DNA positivity in urine and plasma samples was 11 (range: 1-80) and 32 days (range: 2-79), respectively. The median value of BKV DNA copies in urine and plasma were 1.7 × 106 (range: 2.8 × 101 -1.2 × 1014 ) and 1.9 × 103 copies/mL (range: 3-2.1 × 106 ), respectively. Thirteen patients (54.2%) had hematuria with BKV viruria; 8 (33.3%) patients had viremia. The median value of the BKV DNA copies in urine and plasma was 4.4 × 107 (range: 65-1 × 1011 ) and 2.9 × 103 (range: 7-7.8 × 104 ) copies/mL in these patients. Two (15.4%) of the 13 patients with BKV viruria and hematuria were diagnosed with BKV-related HC. BKV DNA viral load monitoring of urine and plasma in pediatric HSCT patients with a high risk for viral infections is valuable for understanding the development of BKV-related HC.