Times of India
02 March 2011
Scientists are now using genetic engineering to modify the immune cells of AIDS patients to shield them from the deadly virus’ effect
In a bold new approach ultimately aimed at trying to cure AIDS, scientists used genetic engineering in six patients to develop blood cells that are resistant to HIV, the virus that causes the disease. It’s far too early to know if this scientific first will prove to be a cure, or even a new treatment. The research was only meant to show that, so far, it seems feasible and safe.
The theory was based on the astonishing case of an AIDS patient who seems to be cured after getting blood cells from a donor with natural immunity to HIV nearly four years ago in Berlin. The cell transplant appears to have cured both problems, but finding such donors for everyone with HIV is impossible, and transplants are risky.
Researchers are seeking a more practical way to achieve similar immunity using patients’ own blood cells.
"For the first time, people are beginning to think about a cure" as a real possibility, said John Zaia, head of the US government panel that oversees gene therapy. Even if the new approach doesn’t get rid of HIV completely, it may repair patients’ immune systems enough that they can control the virus and not need AIDS medicines.
This is the first time researchers have permanently deleted a human gene and infused the altered cells back into patients. Other gene therapy attempts tried to add a gene have not worked against HIV. The virus can damage the immune system for years before people develop symptoms and are said to have AIDS – acquired immune deficiency syndrome. The virus targets immune system soldiers cells called T–cells. It usually enters these cells through a protein receptor called CCR5. Some people lack both copies of the CCR5 gene and are naturally resistant to HIV.
In the study, six men with HIV had their blood filtered to remove a small percentage of their T–cells. The genesnipping compound was added in the lab, and about one–fourth of the cells were successfully modified. The cells were mixed with growth factors to make them multiply and then infused back into the patients.
Three months later, five men had three times the number of modified cells expected. As much as 6 per cent of their total T–cells appear to be the new type – resistant to HIV, Lalezari said.
The sixth man also had modified cells, but fewer than expected. In all six patients, the anti–HIV cells were thriving nearly a year after infusion.
The only side effect was two days of flulike symptoms. It will take longer to determine safety, but several AIDS experts said they were encouraged so far. AP
Friday, Feb 24th
Last update:05:44:44 AM IST