One of the most fashionable treatments for disease, gene therapy, has so far made little headway in tackling one of the most modish of illnesses, AIDS and the human immunodeficiency virus (HIV) that causes it. 46. {{U}}The idea of gene-therapy treatment for HIV/AIDS would be to create a gene that, when placed in an infected person, would make all of the offspring of the cell into which it was inserted resistant to the virus.{{/U}} Even if the virus continued to destroy the patient's immune cells, new ones that could not be infected would replace them. Eventually, the disease would no longer threaten the health of the patient.
A first step towards this has been achieved by researchers at the University of Pennsylvania and VIRXSYS, a biotechnology firm based near Baltimore. 47.{{U}} Rather than inserting a gene directly, they removed the immune cells from people and replaced them with versions that had been modified to resist the virus. {{/U}}The results were published in this week's issue of the Proceedings of the National Academy of Sciences.
The team treated five infected patients who had not responded to at least two different programmes of treatment using conventional anti-retroviral drugs. They removed from each patient's blood the cells called "helper T-cells" that would normally mobilise the immune response to the virus. 48. {{U}}These were purified and stuffed with a form of HIV that had been altered to carry a mirror image or "antisense" version of a molecule that enables it to multiply. {{/U}}This genetic fiddling disrupted the reproduction of the virus inside infected cells.
Such a small experiment was designed merely to establish whether the approach was safe. But the researchers were pleasantly surprised to find that the number of viruses in each patient dropped. This suggests that the treatment was tackling the disease effectively in difficult patients for whom conventional drugs had failed. 49. {{U}}According to Carl June of the University of Pennsylvania, their immune systems responded "as if they were on a vaccine" and it appeared as though their bodies were "vaccinating themselves" against HIV.{{/U}}
The researchers are now moving to the next phase of study, which will involve more patients, including those whose disease is in its early stages. 50. {{U}}If later trials confirm the early positive results, this approach could prove a useful complement to existing drugs or a future vaccine -- and may even replace them.{{/U}}