A LANDMARK life-saving bone marrow transplant was carried out at a Paddington hospital when an 11-year-old boy donated to his sister.
The patient Stacey Bola, 12, sufffers from sickle cell anaemia, leaving her in severe pain when blood is unable to reach parts of her body.
In January, she suffered a stroke, weakening half of her body because the blood supply was obstructed.
But her younger brother Bradley stepped in an offered to donate his own bone marrow to help cure his sister of the serious disease.
This operation, carried out on Wednesday last week, marked the 100th bone marrow transplant carried out at St Mary's Hospital, in Paddington, since 2001.
"She would have been at high risk of having another stroke if she did not have this transplant, which should cure her of sickle cell disease," said consultant paediatric haematologist Dr Josu de la Fuente.
"People don't realise that blood disorders like sickle cell can lead to serious complications."
Stacey, who received her treatment in the Grand Union ward, said the stroke had left her feeling awful.
"I couldn't walk properly or feel anything," she said. "I was numb. The sickle cell disease means I sometimes have a 'crisis' where my back and chest hurt.
"When I was told my brother was going to donate the bone marrow, it was the best news I have ever had."
Blood is made in bone marrow, so all of Stacey's old bone marrow, which was producing the sickle cells, had previously been destroyed with drugs.
Her immunity against infection has been suppressed so her body does not reject the new bone marrow stem cells she received from her borther.
Stacey will stay in a special isolation room for around three to six weeks while her immune system recovers.
After receiving the transplant, Stacy, from Essex, added: "I can't wait to go back to school and see my friends again."