Association of Neutropenia With One Year Outcomes in Pediatric Kidney Transplant Recipients: A Retrospective Study

Abstract Background : Neutropenia is a frequent complication following pediatric kidney transplantation, often linked to immunosuppressive and prophylactic therapies. The impact of neutropenia on clinical outcomes, such as bacterial infections and transplant rejection, is not well established. This study assessed its association with clinical outcomes during the first year after transplant. Methods : We performed a retrospective analysis of pediatric kidney transplant recipients at a tertiary children’s hospital between June 2018 and June 2023. Multivariable regression analyses assessed associations between neutropenia and one-year post-transplant hospitalization, cytomegalovirus (CMV), Epstein–Barr virus (EBV), and BK polyomavirus (BKPyV) viremia, as well for decline in estimated glomerular filtration rate (eGFR). Therapeutic interventions prompted by neutropenia were also described. Results : Fifty-three patients were included (median age at transplant 10.8 years; 52.8% male) all of whom completed 1 year of follow-up. Thirty-five (66%) experienced 68 neutropenia episodes within the first year. Neutropenia was not associated with hospitalization for bacterial infections (IRR 1.00, 95% CI 0.58–1.73), CMV (OR 0.85, 95% CI 0.18–3.94), EBV (OR 1.06, 95% CI 0.22–5.10), BKPyV viremia (OR 0.52, 95% CI 0.12–2.23), or eGFR decline (β = 0.2, 95% CI − 5.2 to 32.9). In response to neutropenia, 74 treatment modifications occurred: trimethoprim-sulfamethoxazole was reduced in 25.7%; mycophenolate mofetil (MMF) was reduced in 16.2% and discontinued in 1.4%; valganciclovir was reduced in 8.1% and discontinued in 21.6%. Conclusion : Neutropenia after pediatric kidney transplantation was not associated with bacterial infection-related hospitalizations, viremia, acute rejection, or impaired graft function during the first year post-transplant.