Understanding infection risks in pediatric hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation (HSCT) is a vital treatment for both malignant and non-malignant disorders in pediatric patients. While the procedure offers hope for many, infections remain one of the leading causes of morbidity and mortality, especially in allogeneic transplants. Advances in HSCT practices—such as the increasing use of alternative donors, ex vivo T-cell depletion, and cord blood grafts—have improved accessibility, but these innovations have also introduced new infection control challenges. As infection patterns evolve, it becomes increasingly important to understand the underlying risk factors and develop strategies to mitigate these risks effectively.

Published (DOI: 10.1002/pdi3.101) on July 14, 2024, in Pediatric Discovery, this study, conducted at Hong Kong Children's Hospital, presents a comprehensive analysis of infection rates and risk factors in pediatric HSCT. The research delves into the epidemiology of bacterial, viral, and fungal infections in pediatric patients, shedding light on their impact on transplant outcomes.

The study analyzed 100 consecutive pediatric HSCT cases from April 2019 to October 2021. It revealed that 93.2% of allogeneic transplant recipients experienced infections post-transplant, with viral infections being the most common at 90.5%, followed by bacterial (35.1%) and fungal infections (9.5%). In comparison, only 30.8% of autologous transplant recipients had infections. Viral infections showed distinct patterns, with HHV-6 and BK virus (BKV) appearing early after transplantation, while cytomegalovirus (CMV) and Epstein-Barr virus (EBV) persisted throughout the 2.5-year observation period. Ex vivo T-cell depletion was found to significantly increase the risk of viral infections, with hazard ratios ranging from 3.03 to 7.15. Additionally, patients with cancers in second complete remission showed higher bacterial infection rates, while those with gastrointestinal graft-versus-host disease (GVHD) were more susceptible to fungal infections. The study also highlighted a concerning 10% infection-related mortality rate, observed solely in allogeneic HSCT patients with hematological malignancies receiving cord blood or haploidentical transplants. These findings reinforce the critical need for targeted, risk-adapted prevention strategies to reduce infection-related complications.

Dr. Wing Leung, corresponding author of the study, emphasized the importance of personalized approaches in infection management: "Our findings underscore the need for tailored strategies to manage infections in pediatric HSCT. By identifying specific risk factors, we can optimize prophylactic measures and improve patient outcomes."

This study's insights have far-reaching implications for clinical practice. The findings pave the way for the development of risk-stratified infection prophylaxis protocols, particularly for high-risk groups such as pediatric patients with hematological malignancies undergoing alternative donor transplants. By adopting these targeted approaches, infection-related mortality could be reduced, leading to improved transplant success rates. Looking ahead, future research will likely focus on exploring novel antifungal and antiviral therapies, as well as refining existing prophylactic regimens, to further enhance outcomes for pediatric HSCT patients.