Long-Term Clinical and Immunological Outcomes of Transplantation in Inborn Errors of Immunity

Introduction Inborn errors of immunity (IEIs) are rare genetic diseases that affect the immune system, leading to clinical manifestations including severe, recurrent infections, autoimmunity, and immune dysregulation. Allogenic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment available for certain patients; however, the long-term clinical and immunological outcomes are poorly described. We analysed the clinical and immunological characteristics of adult IEI patients who received allo-HSCT in childhood to better understand the long-term clinical and immunological outcomes of transplantation. Method Clinical data and blood samples were collected from patients, and lymphocyte populations were assessed using multiparameter flow cytometry. Results Six IEI patients who received allo-HSCT in childhood were identified and included in the study. Patient ages ranged from 20 to 34 years old and had IEI diagnoses from different categories according to the IUIS phenotypical classification. Clinical outcomes and immune phenotypes were tracked over time, and we observed the resolution of all or most of the clinical manifestations of IEIs in our patients. Post-transplant complications observed varied among patients and included arthropathies, endocrinopathies, and end-organ damage related to adverse drug reactions. Results from immunophenotyping showed that the immune system reconstituted to the normal range in most population studies; however, the level of reconstitution showed high variability among different patients. Conclusion Allo-HSCT is a rational therapeutic approach for IEIs stemming from defects in the hematopoietic compartments. Our study found that allo-HSCT was associated with long-term improvement of IEI symptoms, but immune reconstitution was often incomplete. Patients who undergo childhood transplantation should have ongoing monitoring of their immune system, and further studies are required to correlate persistent immune defects with clinical outcomes.