The research is still early, and it has not been tested as a treatment in humans. But the results are striking.
Type 1 diabetes happens when the immune system mistakenly attacks insulin-producing beta cells in the pancreas. Without those cells, the body can no longer properly control blood sugar, and people often need lifelong insulin.
The Stanford team tried to solve two problems at once.
First, they needed to replace the lost insulin-producing cells.
Second, they needed to stop the immune system from attacking those cells again.
To do that, researchers transplanted both blood stem cells and pancreatic islet cells from an immunologically mismatched donor into mice with autoimmune diabetes.
The goal was to create a “hybrid” immune system, made up of cells from both the donor and the recipient.
That immune reset appeared to work.
In one study, the treatment prevented Type 1 diabetes in 19 out of 19 mice. It also cured nine out of nine mice that already had long-standing Type 1 diabetes.
After the transplant, the animals did not need insulin or immune-suppressing drugs for the six-month experiment. They also did not develop graft-versus-host disease, a dangerous complication where donated immune cells attack the recipient’s body.
The researchers then made the approach gentler.
A follow-up study reduced the radiation dose used before transplant from 225 centigray to just 10 centigray, while still curing five out of five mice with induced diabetes.
That matters because high-dose radiation and harsh immune suppression are major barriers to using stem cell transplants for non-cancer diseases.
There are still big challenges before this could move into people. Human pancreatic islets are limited, donor matching is complicated, and scientists still need to test the gentler version in mice with autoimmune Type 1 diabetes.
