![]() Retroviruses work like this, so were the first choice for the initial gene therapy trials. ![]() Viruses are the obvious choice as they survive and spread by inserting their genes into the host’s genome. But the reality is more complicated, because you need something to integrate the gene into the patient’s DNA and persuade the cells to read it. The concept of gene therapy is simple: insert a working gene into a person with a faulty version, and its product should overcome the defect. ∺ll of the hard work has come to a point where gene therapy could become routine medicine “All of the hard work has come to a point where gene therapy could become a more routine modality of medicine.” “At last, the successes are beginning to be more than the failures,” says Inder Verma at the Salk Institute in La Jolla, California. Her white blood cell count has doubled and today she has the immune system of a normal newborn baby But by August her white blood cell count had nearly doubled, and today she has the immune system of a healthy newborn baby. ![]() That was in April, and she wasn’t expected to show much of an improvement before December. Stem cells were harvested from Nina’s bone marrow and given a working version of the ADA gene, before being injected back in. In its absence the toxin builds up, killing the cells that fight infections. This enzyme usually dispatches a toxic molecule from white blood cells. Three further children – including Nina – have been treated since then, and they too are showing signs of a full recovery.Īll five had a form of the disorder called ADA-SCID, caused by a faulty gene for adenosine deaminase. The children’s immune systems have continued to improve since receiving the treatment, says Bobby Gaspar of Great Ormond Street Hospital in London, who led the trial. Preliminary results for the first two children to receive the improved SCID gene therapy – 18 months ago – were presented at the European Society of Gene and Cell Therapy conference in Madrid, Spain, last week. Gene therapy has come a long way since, and Nina’s case, along with others, mark a turning point: researchers seem to have found a safer way of manipulating our genes. It was the start of a rocky road (see “ Trials and tribulations of gene therapy“). An 18-year-old also died following a reaction to a virus used in gene therapy for a liver condition. But in subsequent trials, four young patients were diagnosed with leukaemia two years after receiving a similar treatment. A virus was used to replace a faulty gene with a healthy one. SCID was the first condition to be treated with gene therapy more than 20 years ago. She has gene therapy – and its latest improvements – to thank for it. “The doctors said ‘you need to prepare yourself for the fact that Nina probably isn’t going to survive’,” says Graeme.Ī year-and-a-half later, Nina is a happy little girl with a functioning immune system. It is also known as “bubble boy” disease, since people affected have to live in a sterile environment. She had been born without an immune system due to a genetic defect. It turned out Nina had a condition called severe combined immunodeficiency (SCID).
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