Adult stem cells may have cured young Brazilian diabetics of their ailment. "It's the first time in the history of type 1 diabetes where people have gone with no treatment whatsoever," says Dr Richard Burt, of Northwestern University. An accompanying editorial in the Journal of the American Medical Association says that the results will stimulate more research which could prevent or reverse type 1 diabetes.

Dr Burt and his colleagues received some criticism for the ethics of the study, which involved only 15 patients, one as young as 14. He says that he needed to go to Brazil as US doctors were not interested in his approach. He worked there with Dr Julio Voltarelli. The treatment involved stimulating the body to produce new stem cells and harvesting them from amongst blood cells. Several days of high-dose chemotherapy shut down the immune system, stopping the destruction of the few remaining insulin-producing cells in the body. Then the harvested stem cells were reinjected to help build a healthier immune system.

The study was small and preliminary, but suggests that the devastation of type 1 diabetes may be curbed by adult stem cells. "It's the threshold of a very promising time for the field," says Dr Jay Skyler, author of the JAMA editorial.