A young girl spontaneously switched blood types and took on her donor's immune system following a liver transplant, doctors told French news agency AFP Thursday.
It was the first time doctors had seen such an occurrence, according to a report in this week's New England Journal of Medicine.
Demi-Lee Brennan of Australia was seriously ill with liver failure when she received the transplant at Sydney Hospital.
Nine months later, doctors discovered the girl, who was age 9 at the time, had changed blood types and switched immune systems after stem cells from the new liver migrated to her bone marrow.
Michael Stormon, a hepatologist treating her, said the girl is now age 15 and doing well.