Bk virus infections in pediatric patients with bone marrow transplantation

BK virus (BKV)-associated hemorrhagic cystitis is a common complication in patients after hematopoietic stem cell transplantation (HSCT). The aim of this study was to investigate the incidence of BKV infection in pediatric patients receiving HSCT. Total 51 patients aged between 16 months and 16 years old and followed up between November 2015 and November 2016 were included in the study. The patients were monitored by quantitative real-time PCR (Anaolia Geneworks, Türkiye) for the detection of BKV DNA in urine and blood. Of patients, 46 received allogeneic HSCT and 5 autologous HSCT. BKV DNA positivity was detected in urine and/or blood of total 27 (52.9 %) patients in whom 26 of 46 patients (56.5 %) with allogeneic transplantation and 1 of 5 patients (20 %) with autologous transplantation. BKV viral load in urine greater than > 107 copies/mL required for preemptive treatment was detected in 26 % (12/46) of patients received allogeneic HSCT. The development of hemorrhagic cystitis was prevented in 9 (75 %) of the 12 patients given preemptive treatment, while 3 (25 %) cases developed hemorrhagic cystitis and cured by treatment. BKV viruria was detected greater than > 109 copies/ml in two weeks before the onset of hemorrhagic cystitis and was accepted as a prognostic indicator for predictive diagnosis of hemorrhagic cystitis. BKV viremia was found greater than > 104 copies/ml in only 1 patient within two weeks before the onset of cystitis. In conclusion, the screening for BKV infection, especially BKV viruria in HSCT patients, is recommended for the predictive diagnosis of hemorrhagic cystitis in patients at high risk.