November 11, 2002 01:46 PM ET
By Merritt McKinney
Scientists have tinkered with white blood cells to make them target other immune cells that turn against the body in multiple sclerosis (MS) and other autoimmune diseases.
Using these genetically altered cells, Dr. Terrence L. Geiger of St. Jude Children's Research Hospital in Memphis, Tennessee, and colleagues were able to alleviate an MS-like illness in mice.
The study "provides a new approach using gene therapy for selectively eliminating or disabling cells that cause autoimmune disease," Geiger told Reuters Health.
In MS, the slow destruction of myelin--the thin, protective coating that insulates nerve fibers in the brain and spine--can lead to numbness, muscle weakness and stiffness, impaired vision and coordination problems.
MS, like lupus and rheumatoid arthritis, is believed to be an autoimmune disease, meaning that the immune system turns against the body's own cells. These autoimmune attacks are launched by misdirected white blood cells called T-cells.
To counter autoimmune attacks, Geiger and his team tested a strategy of making other T-cells target and kill the wayward T-cells. They did this by genetically altering normal T-cells to have receptors that recognize the T-cells involved in autoimmune attacks.
In laboratory experiments, the rogue cells latched onto the receptors of these therapeutic T-cells, which then multiplied and killed the destructive T-cells. The approach also was effective in mice that were prone to develop experimental autoimmune encephalomyelitis, or EAE, a condition that, like MS, destroys myelin and is used by researchers to mimic MS in mice.
The illness became less severe in mice treated with the therapeutic T-cells, the researchers report in the advance online edition of the journal Nature Biotechnology. In contrast, symptoms did not improve in mice treated with another type of immune cell that had not been altered. What's more, in another experiment, none of the mice treated with the therapeutic T-cells died, compared with half of the untreated animals. The benefits of the therapy lasted more than 75 days, according to the report.
Despite the promising results, doctors won't be using the therapy in patients anytime soon. Because the research was performed in the lab and in animals, not in people, Geiger cautioned that additional research "will be important to demonstrate how to maximize this approach's efficacy and to clarify any potential for harm prior to considering its use in patients."
SOURCE: Nature Biotechnology 2002;10.1038/nbt758.
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