Viral infections after hematopoetic stem cell transplantation in children with acute lymphoblastic leukemia: the Polish experience

Introduction: Allogeneic hematopoetic stem cell transplantation (allo-HSCT) is one of the therapeutic options in pediatric acute lymphoblastic leukemia (ALL). Most previous analyses have concerned the reactivation of viruses in the entire population of children after allo-HSCT, regardless of the disease entity being an indication for transplantation. In our report, we aimed to evaluate the occurrence, etiology, risk factors and clinical outcome of viral infections in pediatric patients with ALL. Material and methods: 83 post-HSCT ALL patients from 2020 through 2021 were analyzed for infections with polioma BK virus (BKV), cytomegalovirus (CMV), Epstein-Bárr virus, severe acute respiratory syndrome coronavirus 2, adenovirus, respiratory syncytial virus, norovirus, rotavirus, influenza, human herpes virus-6, parainfluenza and rhinovirus. Results: Viral infections were detected after 41% of the transplantations. The viruses most commonly detected were BKV (26.2%) and CMV (23.8%). The analyzed potential risk factors for viral infections were total body irradiation (TBI), graft-versus-host disease, complete remission status, and donor type. Overall survival in the investigated group was 0.815. Conclusions: Complications occurred more frequently in patients without TBI and we did not confirm the impact of other factors. Viral infections in children with ALL after allo-HSCT remain a significant problem. Our results highlight the importance of frequent monitoring and anti-viral prophylaxis