A limitation of matched-donor bone marrow transplant for ADA deficiency is:

• A. It guarantees a permanent cure in all cases
• B. It has no risk of graft-versus-host disease
• C. It may fail to cure if engraftment fails or donor is not perfectly matched
• D. It eliminates the need for ongoing medical follow-up

Answer: (C)

The key idea here is that a matched-donor bone marrow transplant for ADA deficiency isn’t automatically a guaranteed cure. The success of this approach depends on the transplanted stem cells engrafting properly in the recipient’s bone marrow and on how closely the donor matches the recipient’s immune system.

If engraftment fails, the donor cells don’t take hold, so the recipient remains with their own immune deficiency and the disease is not cured. Even with a perfectly matched donor, there can still be issues like graft rejection or only partial engraftment, leading to mixed chimerism rather than a complete, lasting immune reconstitution. These possibilities mean the transplant might not fully resolve the metabolic and immune problems caused by ADA deficiency.

Because of these realities, you don’t have a guaranteed permanent cure, and there is still a need for careful long-term follow-up after the transplant to monitor immune function, manage complications, and address any remaining disease activity. The options that claim no risk of graft-versus-host disease or that eliminate ongoing follow-up aren’t accurate, since GVHD risk, needs for monitoring, and potential late effects are real concerns even with a matched donor.