A story like this is best summed up just like a doctor put it by saying the case is "extremely unusual." After receiving a liver transplant at the age of nine, Demi-Lee Brennan's immune system literally switched over to that of her donor's. She now has a different blood type, and doctors say nothing like this has ever been observed before.

In the beginning, they discovered she had liver failure and required a transplant. But after the operation, stem cells from the transplanted organ made their way to her bone marrow. This is how the incredible switch took place. Now doctors are trying to figure out if they can replicate the same results for other transplant surgeries.

Considering that the human system can reject transplants, it would be extremely beneficial to find a way to make the body change its own makeup to adapt a healthier organ. Demi-Lee is perfectly fine now, so maybe some day we'll see these amazing results on a regular basis!