Dr Flossie Wong-Staal of the University of California in San Diego, and a leading Aids researcher, said trials should start within a year.
'This might seem like an unreachable goal right now, but we should bear in mind that gene therapy is a rapidly developing field,' she told the 10th International Conference on Aids in Yokohama, Japan. 'It is hoped that the urgency of the Aids epidemic will provide impetus for this technology.'
Dr Wong-Staal and her team plan to remove blood from the baby's umbilical cord. The blood contains stem cells which are normally found in the bone marrow, and are involved in the production of new blood cells. A new gene will then be inserted into the genetic material of the stem cells in the laboratory. The gene enables the cell to make an enzyme, known as a hairpin ribozyme, which slices up and destroys the HIV genetic material that it needs if it is to replicate itself.
The treated stem cells will then be injected back into the baby where they will produce white blood cells containing the enzyme. If one of these cells is infected by HIV, the enzyme will attack it before it becomes established in the cell. If it fails, the enzyme will attack the virus again when it starts to replicate.
Initially, each baby will be given altered blood cells taken from its own umbilical cord, but eventually, doctors hope to mass-produce stem cells which will be available as a routine injection. The ultimate goal is to develop a simple Aids treatment that can be given in a single injection to protect infants at risk.
The proposed therapy has yet to be approved by the American Food and Drug Administration and the National Institutes of Health, but Dr Wong-Staal said: 'We don't expect a long delay and treatment should begin in 1995.'
Dr Wong-Staal's approach is one of several gene-therapy treatments now in development for HIV infection.
Drug therapy, the first line of attack, has proved disappointing. The virus can mutate rapidly to evade the impact of drugs now used, and resistance is a growing problem. Vaccine development is progressing slowly with no real prospect of a successful preventive injection before 2000 at least.
Dr William Paul, director of the US Office of Aids Research, said there was 'great enthusiasm about the potential of gene therapy to limit the capacity of cells to support the growth of the virus'. Although no one knows for sure if gene therapy will work any better than drugs, treating infection at the earliest stages - in infected infants or those at risk - is believed to hold the best prospects for prolonging life.
Researchers working for the Ares-Serono drug company told the conference that a genetically- engineered form of growth hormone appeared to halt the dramatic weight loss and wasting associated with Aids.
A preliminary 12-week trial in 178 people showed that the weight gain was due to an increase in 'lean body mass' and not fat, suggesting that the hormone was reversing or slowing down the breakdown of protein in the body.
Aids researchers and activists yesterday called for better awareness of the disease to prevent the marginalisation of sufferers. Junsuda Suwunjundee, a Thai woman with Aids, told the conference: 'Death no longer frightens us. What frightens us is how we can continue to live in society.'
Ms Suwunjundee, a member of a Thai Aids support group, said that when she revealed she had the disease her family was reluctant to carry on living with her. 'They were afraid to have me live in the same house so I decided to leave home for the clinic. As we are not welcome in some hospitals, we must go to the few hospitals that will accept us.'
She said society had a responsibility to secure the fundamental human rights of people with HIV.
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