BK Virus Infections in Pediatric Kidney Transplant Recipients: A Single-Center Experience

Objective: BK virus infections and associated nephropathy are important causes of morbidity in kidney transplantation. This study aimed to evaluate the incidence, clinical, and outcome characteristics of BK virus infections among pediatric kidney transplant recipients followed up at a tertiary center. Methods: Among 66 patients who received kidney transplants between January 2011 and January 2022, 12 patients with BK virus viruria and/or viremia were retrospectively analyzed using medical records and an institutional transplant registry. Results: The incidence of BK virus viremia and/or viruria was calculated as 18% and BK virus infections and associated nephropathy was 13.6%. The median age at the time of transplantation was 13 years (interquartile range 10.1-14.8) and from transplantation to BK virus detection was 11 months (interquartile range 3.2-50.2). Median serum creatinine levels at the time of BK virus viremia were 0.9 mg/dL (interquartile range 0.8-1.2), median glomerular filtration rate 79.5 mL/min/1.73 m(2) (interquartile range 59.5-101.2). Kidney biopsy was performed in all patients and showed BK virus infections and associated nephropathy in 9 (75%). In all patients rmycophenolate mofetil was either reduced or stopped and in 67% steroid doses were reduced. Mycophenolate mofetil was switched to sirolimus and tacrolimus to cyclosporin-A in 92% and 16.6% of the patients, respectively. Ciprofloxacin was used in 92%, intravenous immunoglobulin 83%, cidofovir 75%, and leflunomide 58% of the patients. Median follow-up was 38.5 (interquartile range 28-84.2) months and the median estimated glomerular filtration rate at the last visit was 56 mL/min/1.73 m(2) (interquartile range 48-80.5). There was no significant difference between baseline and follow-up estimated glomerular filtration rate levels (P = 0.146). Conclusion: Although BK virus may cause devastating complications. Routine monitoring and prompt intervention, mainly immunoreduction, may prevent graft loss.