These diseases are caused by the faulty production of hemoglobin, the protein in a red blood cell that transports oxygen to the tissues in the body. The result offers hope that the same approach may work in people. But when both copies are damaged, children often die at a young age. Severe beta-thalassemia is treated with regular blood transfusions, and, in some cases, a bone marrow transplant. But bone marrow transplants are not available to everyone, and are risky because of complications with the immune system.
Transfusions can cause a dangerous build-up of iron in the heart muscle.
If a patient's own bone marrow cells are removed and have a healthy beta-globin gene inserted, the cells are returned to the patient and normal hemoglobin should be produced without any complications with the immune system, he says. The team tested this approach in mice. The results are presented in a recent issue of Nature . Sadelain's group packaged the healthy beta-globin gene and an adjacent area of the DNA, which controls when and where the gene is turned on, into a virus. The virus was then mixed with bone marrow cells that had been removed from mice with beta-thalassemia.