A group of patients with type 1 diabetes were able to live without insulin injection for months after getting treatment involving their stem cells. Type 1 diabetes is an autoimmune disease in which the immune system attacks and destroys the insulin-producing cells within the pancreas.

The new treatment is known as autologous nonmyeloablative hematopoietic stem cell transplantation (HSCT) involving many steps. Initially patients were given drugs to stimulate production of blood stem cells. Then the blood stem cells were removed and frozen. Patients were given the toxic drugs that killed their circulating immune cells. After this the harvested blood stem cells were put back into the patient.

23 people, mostly boys and young men, were treated with the new treatment. Half of the patients became insulin free for an average of two and a half years. Four patients remained insulin free for at least three years and one patient went without insulin injections for more than four years.

But the use of highly toxic immune-system suppressing drugs led to some troubling side effects. Two patients developed pneumonia and nine developed low sperm counts.