A cohort of allogeneic hematopoietic stem cell transplantation for pediatric rare diseases (allo-HSCT-PRD): design and preliminary results.

Rare diseases in children have attracted widespread attention worldwide due to their rarity and difficulty in diagnosis and treatment. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is emerging as a promising and curable therapy for multiple rare diseases. However, rare disease research in China is relatively backward, prompting us to construct the first cohort of allo-HSCT for pediatric rare diseases (allo-HSCT-PRD) involving those who underwent allo-HSCT at the Children's Hospital of Fudan University from 1 January 2014 to 31 October 2024. We concurrently developed a standard data collection, management, and follow-up process, and a dedicated multidisciplinary team to support the work. The allo-HSCT-PRD consisted of 480 participants who were categorized into inborn errors of immunity (IEI) and inborn errors of metabolism (IEM), with 428 and 52 cases, respectively. Among all subjects, the engraftment rate was 84.6%, and the 5-year overall survival (OS) rate was 78.5% (95%CI 74.9% - 82.4%). In particular, patients in the IEM group had greater age and higher implantation and 5-year OS rate. Our next step is to extend our work experience to build allo-HSCT-PRD into a multi-center cohort to boost the development of disease models, exploration of pathogenesis, and clinical trials for new medications.