Hundreds of thousands of people could be cured of autoimmune diseases like arthritis, multiple sclerosis, diabetes and lupus after scientists discovered how to make stem cell transplants safe.

Autoimmune diseases trigger the body into attacking itself but transplants of bone marrow stem cells from healthy donors have been shown to reset the immune system and reverse fatal conditions.

However doctors have been reluctant to carry out the treatments as before the healthy cells can be given, the patient must be stripped of the malfunctioning immune system using radiotherapy or chemotherapy.