Bone marrow donor pool could expand

The most suitable people to donate bone marrow to treat infants with leukaemia are Human Leukocyte Antigen (HLA) -matched sibling donors (MSD). However, these brothers and sisters are only available for one third of those in need of bone marrow. The remaining two thirds must depend on mismatched related donors (mmRD) and allelic matched unrelated donors (URD).

An international group of researchers, including two from King Faisal Specialist Hospital & Research Center in Saudi Arabia, conducted a retrospective study of 1,625 patients who received bone marrow donations between 1993 and 2006 to determine whether mmRD grafts lead to similar outcomes as URD and re-evaluate the role of transplants using mmRD.

The researchers confirm that the best results are obtained from MSD transplantations compared to all other donors. Though inferior to MSD, they found that mmRD and URD both yield similar results in overall survival rates post-operatively.

They advocate that, when a MSD is not found, clinicians should consider mmRD, such as parents, cousins and siblings, as a useful alternative to a matched URD. Under some circumstances, finding a related donor can be easier than a matched unrelated one. This is especially true in regions that have large extended families, such as the Middle East.

According to the authors, further research into partial mismatches from related donors may yield a subgroup of mmRD just as suitable as MSD. However, most clinics do not report the rates of allele mismatches in related donors, which prevented the researchers from looking into this further during their study.

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