Scientific report 2025 of the Inborn Errors Working Party (IEWP)

2025 has been the first year for Claire Booth and myself as Co-Chair and Chair, respectively, of the IEWP of the EBMT. It has been characterised by key studies, collaborative achievements and educational events in the field of HCT and gene therapy for Inborn Errors of Immunity and Metabolism.

Several key studies have been published. The retrospective study on haploidentical HSCT in chronic granulomatous disease (Blood) has provided valuable insights into transplantation strategies in this complex Inborn Error of Immunity (IEI). Another notable retrospective study focused on HCT outcomes in purine nucleoside phosphorylase deficiency (Blood) covering both immunological and neurological aspects of the disease and highlighting how early diagnosis is critical to improve outcomes.

Other studies investigated HCT outcomes for STAT1 gain-of-function disease following JAK inhibition bridging (J Hum Immun) and late effects after HCT in patients with HLH, the latter in collaboration with the Histiocyte Society, PDWP, and TCWP (JACI). Another relevant publication focused on clinical phenotypes and treatment modalities in 32 JAGN1-deficient patients, in collaboration with ESID (Blood Advances).

Moreover, pivotal studies are ongoing that will impact the landscape of HCT for inborn errors, including research on patients with interferon gamma receptor 1/ 2 deficiencies, cartilage hair hypoplasia, FHL2 and FHL3, and long-term outcomes in Chediak-Higashi syndrome. 

In terms of educational events, the 25^th IEWP Annual Conference was held in Freiburg, Germany in September 2025, bringing together over 180 attendees, including 12 nurses, to share knowledge and advance the field on HCT and cellular therapies, including ex-vivo gene therapies, in these disorders. Moreover, the third edition of IEWP Spring School on HCT in Inborn Errors of Immunity, took place extremely successfully in Seville, Spain in April 2025 and gave the chance to over 30 international experts and junior attendees to deepen knowledge and share expertise on cellular therapies in these disorders.  Indeed, many of the attendees from previous Spring Schools now sit on the IEWP Juniors Committee, helping to shape the Annual Meeting and support the community.

The IEWP continues to advance the frontiers of scientific research and clinical practice by promoting collaboration between Europe and the United States, with the goal of enhancing patient outcomes and optimising transplant protocols.