BMJ 2002;324:872 ( 13 April )
Owen Dyer, London
The first success for gene therapy in the United Kingdom has restored health to an infant who last year was confined to a sterile room and needed to be kept alive by a ventilator.
Rhys Evans, now 18 months old, suffered from X chromosome linked severe combined immunodeficiency disorder, popularly known as "baby in the bubble" syndrome, after the sterile plastic spheres used to protect some babies from infection. He now lives a normal life at home.
At a press conference last week his doctors pronounced themselves "ecstatic" about the boy's recovery. "We're very pleased to announce the first successful cure of a patient in the United Kingdom by gene therapy," said Professor Christine Kinnon, director of the Centre for Gene Therapy of Childhood Disease at the Institute of Child Health, London, who collaborated with doctors at Great Ormond Street Hospital in treating Rhys.
Dr Adrian Thrasher, consultant paediatric immunologist at Great Ormond Street Hospital, was more cautious: "I'd like to say that Rhys is cured, but we can't say that. He will be followed up for years and years."
Rhys's condition appeared soon after his mother stopped breast feeding him at four months. A series of chest infections developed into severe pneumonia. "He was skin and bones, too weak to hold his head up," said his father, Mark Evans.
The standard treatment for the condition is a bone marrow transplant, but Rhys had no obvious donors. A US donor was finally located at the same time that gene therapy became available. The parents opted for the new treatment, partly to avoid the chemotherapy that accompanies transplantation.
The treatment began with the extraction and freezing of cells from Rhys's bone marrow. A mouse retrovirus was genetically engineered to carry a healthy copy of the gene that was defective in Rhys. A bag containing the retrovirus was connected to a bag of his bone marrow. The virus then spliced the healthy gene into the stem cells, which were then reinserted into the bone. Within a few months his lymphocyte count began to climb rapidly.
Three months ago a second, 10 month old baby underwent gene therapy
for severe combined immunodeficiency disorder at Great Ormond Street. That
patient shows even more promising results than did Rhys at the same stage,
Dr Thrasher said.
© BMJ 2002