Donor type for transplant in pediatric patients with acute lymphoblastic leukemia

This study aimed to investigate the impact of donor type for stem cell transplant in pediatric acute lymphoblastic leukemia patients. 

This study concluded that the outcomes of transplants from matched donor and HLA-identical sibling donors are similar.  

Hematopoietic stem cell transplant (HSCT) is a procedure in which a person receives blood-forming stem cells from a donor. HSCT can be used for the treatment of acute lymphoblastic leukemia (ALL). Human leukocyte antigen (HLA) matching involves choosing a donor and patient that have similar HLA markers. HLA matching promotes engraftment (growth of new healthy blood cells) and reduces the risk of graft-versus-host (GVHD) disease. GVHD is a complication that can occur after transplant where the patient's body sees the new cells as foreign and attacks them.  

Donors for HSCT can be HLA-identical siblings or unrelated HLA-matched donors.  

It was not known which donor type (sibling HLA match or matched donor) would provide better outcomes for pediatric ALL patients undergoing HSCT.  

This study involved 348 children and adolescents with ALL who received HSCT. 138 patients received HSCT from HLA-identical siblings (MSD; matched sibling donors) and 210 from unrelated matched donors (MUD). The average follow-up period was 4 years and 7 months.

The 4-year event-free survival (no major complications) for the MSD group was 65% compared to 61% for the MUD group. The overall survival rate for the MSD group was 72% compared to 68% for the MUD group. The frequency of relapse (disease returns) for the MSD group was 24% compared to 25% for the MUD group. Non-relapse mortality (death not related to relapse) for the MSD group was 10% compared to 14% for the MUD group.  

The risk of extensive chronic (cGVHD; long-term) was lower in MUD than in MSD recipients. The risks of severe acute GVHD (aGVHD; short term) and cGVHD were higher in patients who received peripheral blood when compared to those who received bone marrow cells.  

When compared to the absence of aGVHD, mild to moderate aGVHD was associated with a lower risk of failure. When compared to the absence of aGVHD, severe to life-threatening aGVHD was associated with a higher risk of failure and a higher risk of non-leukemic death, despite a lower risk of relapse.  

When compared to the absence of cGVHD, extensive cGVHD was associated with a higher risk of non-leukemic death.  

This study concluded that the outcomes of transplants from a matched donor and HLA-identical sibling donors are similar. It was also concluded that bone marrow should be the preferred stem cell source.