'Immune system transplant' successful in mice

Researchers at the Stanford University School of Medicine have had some success at transplanting adult stem cells into mice to create a new immune system, according to a study published in the journal Science last week. Although it may be many years before the research can be translated into humans, it is hoped that it may one day help to provide treatments or even cures for people with common immune system disorders, such as multiple sclerosis (MS) and arthritis, or genetic blood diseases, such as sickle cell.

Currently chemotherapy or radiotherapy are needed to destroy the patients own immune system before a bone marrow transplant may be carried out. This means that, due to the associated side affects - including brain damage, increased risk of cancer or infertility - only patients with life-threatening disorders can be offered bone marrow transplants at present.

People with MS, a non-life-threatening disease, have a defective immune system which means that immune cells attack the person's own body. Having a born marrow transplant, without the risk of dangerous side affects, could potentially cure patients with MS by providing them with a new immune system which may not attack the body.

The researchers, lead by Professor Irving Weissman, injected the mice with a toxin that only sticks to blood-forming stem cells, thus destroying them without damaging the bone marrow or other surrounding tissues. 'When we transplanted new blood-transforming stem cells into the mice, those cells took up residence in the bone marrow and established a new blood and immune system', said Professor Weissman. 'It is essentially a surgical strike against the blood-forming stem cells', he said.

Dr Laura Bell, research communications officer at the MS Society was optimistic about the potential for new treatments. 'Stem cell studies are an important avenue of research which holds promise in terms of treatments for MS', she said. 'This early stage is interesting and we look forward to seeing how the work translates into studies in people with MS'.

Professor Edward Tuddenham of Royal Free Hospital in London believes the potential for stem-cell transplants may also help people with genetic blood diseases. 'For those whose blood stem cells contain a severe genetic defect such as that causing sickle cell anaemia, replacing them with normal stem cells would enable restoration of normal blood', he told the Daily Telegraph.

Professor Weissman said that many aspects of the technique would need to be adapted before the procedure can be tested in humans, but that he is optimistic about the potential for future benefits.