For decades, type 1 diabetes has been one of regenerative medicine’s toughest challenges. Today science has made enormous strides: it is possible to produce functional pancreatic beta cells in the laboratory from stem cells. But the real problem is no longer making them — it is keeping them alive after transplantation. The patient’s immune system, in fact, represents a formidable obstacle. On one hand it recognizes transplanted cells as foreign, triggering rejection; on the o
