RANDALL WESTRICK
graduate student
University of Michigan

Dinah,

Can a person's blood group ever change?

Randall Westrick
HHMI lab associate,
graduate student,
University of Michigan

There is one possible way for a person to change blood type—but not spontaneously—and it requires a major medical procedure known as bone marrow transplantation. The molecules responsible for blood type are specialized sugar molecules that dot the surface of red blood cells, as well as other cells in the body. Normally, a blood transfusion between individuals with mismatched blood types would result in destruction of the donor red blood cells by the immune system of the person receiving the blood transfusion.

The situation is a bit different in a bone marrow transplant, where the entire bone marrow is killed off by drugs. The bone marrow is then replaced by the donor bone marrow cells. This is a bit complicated because there are many genes (called histocompatibility genes) and proteins that need to be matched between donor and recipient in order for the transplant to be successful. For reasons that aren't fully understood, different blood types between donor and recipient do not have a major effect on whether the transplant is successful or not, and a successful transplant between those with mismatched blood types effectively changes the recipient's blood type. This happens in between 20% and 30% of those receiving therapeutic bone marrow transplantation.

03/07/08 22:14