The trial, conducted in the US through the international Type 1 Diabetes TrialNet consortium and published in the New England Journal of Medicine, provides the first conclusive evidence that it is possible to target particular types of immune cells to reduce or prevent the onset of type 1 diabetes.

The compound, called rituximab, specifically targets a type of immune cell known as B cells. B cells organize the immune system and are responsible for telling other cells when and where to attack. Previous research has shown that reducing the number of B cells in mice predisposed to type 1 diabetes resulted in the disease being delayed and even prevented. The big question was whether it would also be the case in humans.

Excitingly, it was. Researchers reported that patients given rituximab treatment had a significantly slower disease progression, better blood glucose control and lower insulin requirements compared to the control group.

Some challenges were experienced, however. Patients on the rituximab treatment were given four doses of the drug over a one year period yet most experienced a decline in effect soon after treatment stopped. Some patients also experienced side effects that, though relatively mild, were not desirable for long term treatment.

Researchers will now conduct further trials to look at ways of prolonging the action of the treatment to ensure the autoimmune process that causes type 1 diabetes is safely prevented in the long term.

While work is yet to be done, this research is the first step towards the development of a safe and effective way to prevent the immune attack behind type 1 diabetes — an essential prerequisite for both disease prevention ongoing protection for insulin-producing replaced or regrown through other means.

Researchers from the Garvan Institute of Medical Research have successfully tested a method of adjusting the immune system for just long enough to receive a tissue transplant and accept it as ‘self’. At no stage, during or after the procedure, is there any need for immunosuppressive drugs.

Lead by Professor Jonathon Sprent, the research team used a special immune boosting “complex” to successfully transplant islet cells into diabetic mice without the need of immunosuppression.

“Under normal circumstances, the body would attack a transplanted organ unless immunosuppressive drugs such as cyclosporin were given,” said Prof Sprent. “In this project, mice were given a substance, or ‘complex’, that altered their immune systems, so that they accepted transplanted cells as their own.”

This complex combines a molecule, interleukin-2 (IL-2), with an antibody. When given to the mice, this resulted in an increase in T-reg cells – the cells that quieten down the immune system, and a decrease in killer T cells – the cells that fight foreign materials.

The challenge for these researchers was that whilst this is the perfect situation for a tissue transplant, the lack of killer T cells means the body would be susceptible to attack from other areas such as infections or cancer cells. By changing testing different versions of the complex, they were able to suppress the immune system temporarily without risking infection.

According to research team member Stacy Walters, the results in mice were extremely encouraging.

“After treatment, the numbers of T regulatory cells dropped over time the immune systems returned to normal in about two weeks. By that time 80% of the mice had accepted the grafts of insulin producing cells as their own. A graft is considered accepted if it’s tolerated after 100 days. We took some mice out to 200-300 days, and not one of them rejected.”

While cautious, Professor Sprent is very encouraged by the results.

“We have yet to determine exactly how the complex works. Once we do, I believe a clinical trial of this very non-toxic agent would be worthwhile.”

“If we were able to duplicate this experiment in humans, it would fulfill the dream of everyone in the transplant field.”

Journal of Experimental Medicine pub online Feb 09