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

Before a bone marrow transplant, it is essential for the donor and recipient to have compatibilities at various informative polymorphic loci to minimize the risk of graft-versus-host disease (GVHD) and transplant rejection. The correct answer states that at least one informative polymorphic locus must be found between the donor and recipient.

This minimum requirement is significant because it indicates that even a single match can reduce the likelihood of complications associated with mismatched histocompatibility antigens. Typically, these polymorphic loci relate to the major histocompatibility complex (MHC) genes or human leukocyte antigens (HLA), which play a crucial role in immune response. A match at one locus allows the recipient's immune system to recognize the donor's cells as less foreign compared to those lacking a match, promoting better integration of the transplanted cells.

While having more than one polymorphic locus is beneficial and generally preferred for increasing compatibility, the fact that only one informative polymorphic locus is required highlights the critical importance of any level of match, particularly in cases where a closer match is not feasible. Thus, the emphasis on having at least one informative polymorphic locus underscores its role in enhancing transplant success and reducing potential adverse effects.