DETERMINANTS OF PEDIATRIC HAPLOIDENTICAL HEMATOPOIETIC CELL TRANSPLANTATION (HCT) WITH POST-TRANSPLANT CYCLOPHOSPHAMIDE (PT-CY): THE INFLUENCE OF DONOR CHARACTERISTICS

Year: 2026

Type: article

Abstract: Introduction Donor age and relationship has emerged as a key modifiable variable in haploidentical hematopoietic cell transplantation, with younger and sibling donors associated with reduced non-relapse mortality and graft-versus-host disease in adult cohorts. Evidence specific to pediatric patients using a uniform post-transplant cyclophosphamide platform, particularly from middle-income countries, remains scarce. Objectives Evaluate the impact of donor age and donor relationship on acute and chronic graft-versus-host disease, graft failure, relapse, event-free survival, and overall survival in a post-transplant cyclophosphamide pediatric haploidentical transplant cohort. COHORT: 142 consecutive pediatric recipients of haploidentical hematopoietic cell transplantation, all receiving post-transplant cyclophosphamide-based graft-versus-host disease (GVHD) prophylaxis at a single pediatric center in a high-middle-income country. Methods Retrospective cohort study. Kaplan-Meier survival plots with log-rank test for group comparisons; cumulative incidence (CI) function for GVHD and graft failure. Multivariable Cox proportional hazards regression adjusted for donor relationship, donor age, cell source, patient sex, disease type (malignant vs. non-malignant), and donor lymphocyte infusion (DLI) for moderate-to-severe chronic GVHD. Primary cutoff: donor age ≤ 18 years (n = 31), 19-30 years (n = 70) and ≥ 31 years (n = 31); secondary cutoff: 1-10 years (n = 11), 11–18 years (n = 20), and > 18 gt; 18 years (n = 111). Results No significant differences were found in overall survival (OS) (p = 0.86), event-free survival (EFS) (p = 0.47), relapse (p = 0.7), death (p = 0.9), or graft failure CI (p = 0.31) between donors in primary or secondary cutoff. MAGIC II-IV acute GVHD was significantly lower with sibling donors versus fathers, mothers, and Others (cousins and aunts) donors (23% vs. 43% vs. 45% vs. 62% at 1 year, p = 0,032). Moderate-to-severe chronic GVHD was significantly lower with Others vs. siblings, father and mother donors (0% vs. 19% vs. 22% vs. 51% at 1 year, p = 0,0059). Multivariate Cox Regression analysis revealed mother donors (HR 3.61, 95% CI 1.68–7.76, p = 0.001) and non-malignant disease (HR 0,24, 95% CI 0.08–0.75, p = 0.014) as significant predictors for moderate-to-severe chronic GVHD. Although not significant, we observed that donors 1-10 years had zero graft failures in 11 transplants vs. 3 failures in 20 transplants of the 11-18 years donor group (p = 0.054). Conclusions In a pediatric haploidentical transplant cohort with uniform post-transplant cyclophosphamide, donor relationship was determinant for acute GVHD and chronic GVHD CI; mother donors were independently associated with augmented chronic GVHD, and non-malignant disease was independently associated with reduced chronic GVHD. There was no improvement nor decline in OS or EFS. Our results provide platform-specific pediatric evidence to guide donor selection where PTCY is standard of care.

Source: Hematology Transfusion and Cell Therapy

DOI: 10.1016/j.htct.2026.106853

Language: English

Topic: Hematopoietic Stem Cell Transplantation

Subfield: Hematology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: diamond

OpenAlex ID: W7223087714

Determinants of Pediatric Haploidentical Hematopoietic Cell Transplantation (hct) With Post-transplant Cyclophosphamide (pt-cy): the Influence of Donor Characteristics