Optimizing Haploidentical Donor Selection for Pediatric Hematopoietic Cell Transplant.

Area of Science:

• Hematology
• Immunology
• Pediatric Oncology

Background:

• Selecting haploidentical donors for pediatric hematopoietic cell transplants requires critical guidance.
• The impact of donor relationship (parent, sibling, extended family) on graft-versus-host disease (GVHD) outcomes is not fully understood.

Purpose of the Study:

• To evaluate the effect of donor age and relationship on acute (aGVHD) and chronic (cGVHD) graft-versus-host disease in pediatric patients.
• To provide guidance on optimal donor selection for pediatric haploidentical stem cell transplantation.

Main Methods:

• Analysis of 1,069 pediatric recipients (<19 years) undergoing hematopoietic cell transplant between 2013-2019.
• Assessment of primary endpoints: aGVHD frequency at 100 days and cumulative incidence of cGVHD at 2 years.
• Multivariable analysis considering donor age (<18, 18-35, >35 years) and donor relationship (parental, sibling).

Main Results:

• Younger donors (<18 years) were associated with significantly lower rates of both aGVHD and cGVHD compared to older donors.
• Parental donors, particularly mothers, were linked to a higher risk of aGVHD and cGVHD compared to sibling donors.
• Maternal donors showed increased GVHD risk irrespective of age, with higher rates of aGVHD and cGVHD compared to sibling donors.

Conclusions:

• Donors under 18 years are associated with reduced aGVHD and cGVHD in pediatric haploidentical transplants.
• Maternal donors are associated with an increased risk of cGVHD.
• Sibling donors should be prioritized for pediatric patients to minimize GVHD risk.