Robert Booth,Tuesday August 26 2008, The Guardian
Scientists have discovered a potential new treatment for diabetes by isolating and killing defective cells which prevent the natural production of insulin.
Researchers at Massachusetts general hospital said last night that they had found a way to isolate and eradicate immune system cells known as “killer” cells that are responsible for wiping out insulin-producing cells in the pancreas.The discovery of the technique opens the door to a potential therapy for patients with type 1 diabetes. It has worked on mice and tests have been carried out on the blood cells of human patients to confirm its potential. A clinical trial is under way.
Type 1 diabetes is an autoimmune disease in which the body’s “insulin factory” – composed of pancreatic islet cells – is gradually destroyed by specialised white blood cells called “killer” T-cells which are defective. The American scientists are effectively proposing a counter-attack against these cells. “Our studies in mice showed that we could selectively kill the defective autoimmune cells that were destroying insulin-producing islets,” said Denise Faustman, director of the hospital’s immunobiology laboratory and an associate professor of medicine at Harvard.
“These results show that the same selective destruction can occur in human cells and connect what we saw in our animal studies with the protocol we are pursuing in our Phase I clinical trial.”
Faustman’s team found that treatment with tumour necrosis factor (TNF), an immune system regulating protein, leads to the death of wayward T-cells while leaving other parts of the immune system unharmed. In a previous study, diabetic mice given the treatment regenerated healthy islet cells and produced normal levels of insulin. Effectively, the mice were cured.Further experiments with blood samples from several diabetic patients confirmed that only “killer” T-cells which threatened the pancreas were targeted by the treatment. Others programmed to attack two common viruses were not affected.
The new research, reported in the journal Proceedings of the National Academy of Sciences, involved T-cells from more than 1,000 patients with type 1 diabetes, other autoimmune disorders, and healthy volunteers. A clinical trial started in March and will last 18 months. Tony Doherty, the interim director of Diabetes UK Scotland, said the research promised an “exciting new intervention”.
“Evidence is still required as to how long this is effective as a treatment in humans and we look forward to seeing the next stage of trials,” he said.