A team of doctors at Great Ormond Street children's hospital, London, has successfully used gene therapy to treat a child born with a life-threatening genetic condition that affects the immune system. Usually, babies with X-linked severe combined immune deficiency (X-SCID) have to live in sterile 'bubbles' to avoid contracting any infections.
The hospital began trials of the treatment in October last year and Rhys Evans, now 18-months old, has been 'cured'. X-SCID is a single-gene disorder affecting only boys. Children with the disease have no working version of a gene that controls the development of the immune system.
The doctors used a similar technique to that used by a Paris team in 2000, which successfully treated children with X-SCID using gene therapy, restoring the immune system of four out of five children. The London team extracted Rhys's bone marrow and, using a retrovirus which had been engineered to make it harmless, inserted a working copy of the gene into some of the bone marrow stem cells, and transfused the marrow back into Rhys. After several months, Rhys started to develop normal immune system cells.
Adrian Thrasher, the consultant paediatric immunologist who led the team said that the outcome of Rhys's treatment was 'really excellent', although it might be somewhat premature to call him 'cured'. His treatment will have to be followed up for many years. A second child at the hospital has also had gene therapy for the same condition, and is said to be doing even better than Rhys was at a comparative time.