How many informative polymorphic loci must be found between donor and recipient before a bone marrow transplant?

For successful bone marrow transplantation, it is crucial to determine the compatibility between the donor and recipient based on human leukocyte antigen (HLA) typing, which involves assessing various loci. The term "informative polymorphic loci" refers to specific genetic markers that can indicate the level of match between the donor and recipient.

Having at least one informative polymorphic locus means that there is sufficient genetic information to evaluate compatibility and to potentially distinguish the donor's tissue from the recipient’s. This minimum requirement is essential, as it allows for the identification of specific markers that can predict the likelihood of graft-versus-host disease (GVHD) and other complications that arise post-transplant.

While identifying more loci (such as five or ten) can enhance the precision of matching and improve transplant success rates, the fundamental requirement is to have at least one. This ensures that there is a baseline genetic assessment that can inform the transplant teams about potential compatibility.