take on the immune system and blood type of her organ donor

Demi-Lee Brennan, 15, (centre) with her sister Stacey and her mother, Kerrie Mills, is the first patient to take on the immune system and blood type of her organ donor.

SHE'S got purple highlights in her hair and bright blue fingernails, but to doctors at the Children's Hospital at Westmead, Demi-Lee Brennan is a one in 6 billion miracle.

The 15-year-old liver transplant patient has defied science by being the first person in the world to take on the immune system and blood type of her donor, negating the need for anti-rejection drugs for the rest of her life. The phenomenon, which has been documented in the New England Journal of Medicine, has amazed doctors, who say they have no idea how it occurred.

Demi-Lee, of Gerroa on the South Coast, was nine when she contracted a virus that destroyed her liver. She was given less than 48 hours to live until a donated liver from a 12-year-old boy became available.

"She's my little hero," her mother, Kerrie Mills, said yesterday.

"When she was admitted to intensive care, she was very sick, and yellow and had to be put on a ventilator. We were told we were losing her."

With only hours to spare, Demi-Lee underwent a 10-hour operation and was started on an extensive cocktail of immunosuppressant drugs, the standard fare for all transplant patients to ensure their bodies do not reject the donated organ. Nine months later, when her condition worsened and she was re-admitted to the hospital, doctors were shocked to find her blood type had changed.

The head of haematology, Julie Curtin, said she was stunned when she first realised Demi-Lee was now O-positive, rather than O-negative.

"I was convinced we had made a mistake, so we tested it again and it came up the same. Then we tested her parents and they were both O-negative, so it was confirmed that Demi absolutely had to have been O-negative."

Dr Curtin said Demi-Lee's blood began to break down, requiring more medications.

"We then realised it was her own residual cells which were causing the problem and we needed to get rid of them. And that's when we knew we had to convince the doctors that Demi's immunosuppressant drug regime should be stopped, rather than increased."

But pediatric nephrologist, Stephen Alexander, says he wasn't easily convinced. "We didn't believe this at first. We thought it was too strange to be true," Dr Alexander said. "Normally the body's own immune system rejects any cells that are transplanted … but for some reason the cells that came from the donor's liver seemed to survive better than Demi-Lee's own cells. It has huge implications for the future of organ transplants."

Demi-Lee, who has now been off all immunosuppressants for three years, is playing sport and working towards her school certificate. "I feel quite normal, it's almost like it never happened," she said yesterday. "I can't thank the donor's family enough, and the doctors, for giving me this second chance at life."

Demi-Lee has her sights on starring on Australian Idol. "That's partly why I've dyed my hair black. I'm a rock singer."

Sorce: theage.com.au