A 15-year-old Australian girl has changed her blood group from O negative to O positive and taken on the immune system of her organ donor, media reported Friday.
Demi-Lee Brennan, called by doctors as "one-in-six-billion miracle," received a donor liver when she was 9 years old after her own liver failed.
Her new liver's blood stem cells then invaded her body's bone marrow to take over her entire immune system, meaning the teen no longer needs anti-rejection drugs.
Doctors from Sydney's Westmead Childrens' Hospital said they had no explanation for Brennan's recovery. "There was no precedent for this having happened at any other time, so we were sort of flying by the seat of our pants," said Michael Stormon, a pediatric hepatologist.
"It's like my second chance at life," Brennan said, recounting how her body achieved what doctors said was the holy grail of transplant surgery. "It's kind of hard to believe."
Stuart Dorney, the hospital's former transplant unit head, said Brennan's treatment could lead to breakthroughs in organ transplant treatment, because normally the immune system of recipients attacks the transplanted tissue.
Rejection is normally treated with a combination of drugs, although chronic rejection is irreversible.
Only seven-in-10 transplant operations in Australia are successful after a five-year period due to rejection complications.