Islet transplants were first attempted back in the 1970s. Dr. Alex Rabinovitch, also from the University of Alberta, took them on as a serious research project in 1987 or 1988, and never achieved a success rate that reached 10%.
What Dr. James Shapiro, Dr. Ray Rajotte, and Dr. Jonathan Lakey did was bring that up to a level of 80% by changing the immunosuppressing mixture, and that has resulted in a higher than 80% success rate after one year. What happens is that the success rate declines drastically over five years--so of course it took until 2005 before there were reviewable numbers--and therefore more work is required on that.
Is it because the T cells are coming back to attack the new islet cells? We don't know. Because it's a transplant, it also requires exposure to immunosuppressants, which is a risk not worth putting on the heads of young children and otherwise healthy diabetics. Those are the issues that are currently being dealt with through JDRF-funded research.
And I may add that because of the success of the researchers at the University of Alberta, 12 different protocols, around the world, copying Edmonton, which will be slightly different, have been tried or put in place. So we're trying to advance the timeline by having different researchers try different protocols and share information.