Hope for safer bone marrow transplants

Guardian News ^ | November 23 2007 | Ian Sample

[Coleus]

Patients with common immune disorders such as multiple sclerosis and rheumatoid arthritis could one day be treated with bone marrow transplants, scientists claimed yesterday. Hopes for the new treatment follow the development of a more efficient transplant technique which avoids the need for radio- or chemotherapy, both of which have potentially dangerous side-effects.

Traditional bone marrow transplants are used to treat only life-threatening conditions, such as leukaemia or lymphoma. The treatment infuses healthy adult stem cells into the patient, which then form fresh blood and immune cells. But before the transplant can be done, patients must receive a course of radiotherapy or chemotherapy to wipe out the defective cells in their bone marrow. The therapy can cause widespread damage, leaving patients brain damaged, at greater risk of cancer, or infertile.

Researchers at Stanford University's institute for stem cell biology and regenerative medicine reasoned it might be possible to perform bone marrow transplants without needing risky therapy beforehand. In theory, it would allow doctors to treat auto-immune disorders such as multiple sclerosis, rheumatoid arthritis and type one diabetes by giving patients a new, healthy immune system. In a study in mice, Professor Irving Weissman, who led the research, used antibodies to kill off blood and immune system stem cells in the bone marrow. They found the antibodies destroyed more than 98% of the targeted cells. "It is essentially a surgical strike against the blood-forming stem cells," said Weissman, whose study appears in the journal Science. The team was then able to transplant healthy stem cells into the animals, which developed into a new blood and immune system. Although the work is at an early stage, it offers hope for a radical new treatment of common debilitating conditions for which there are currently no cures.