"We kill the immune system and rebuild it with stem cells from the patient," says Julio Voltarelli, a physician and researcher at the University of Sao Paulo, who led the research. "We can see after transplant that the immune system is now healthy." This type of treatment would only be effective in newly diagnosed diabetics, who still have some beta-cell function left to preserve. For patients with more-advanced forms of the disease, scientists are working on cell transplants to replace lost islet cells, using cells from donor organs and, eventually, from embryonic stem cells.