Thousands of people each year are diagnosed and lose their fight with blood diseases such as sickle cell and leukemia, but a new bone marrow transplant method is expected to save many of those lives in the future.
Bone marrow transplants have long been used to add years to people’s lives, but too often the recipient of the transplant would die from an unrelated infection while undergoing treatment. High doses of radiation and chemotherapy were given before a bone marrow transplant to kill off the bad cells and make room for the new. Too often, however, before the newly transplanted cells began growing and replacing the exhausted immune system the patient would contract an infection that the weakened immune system could not fight.
The new procedure currently being tested in hospitals around the country introduces the donor marrow before the patients’ immune system is depleted. The recipient and the donor cells actually work together to form a sort of hybrid immune system.
Usually the patient will receive high doses of chemotherapy and/or radiation to eliminate the unhealthy bone marrow. The new stem cells are injected intravenously, like a blood transfusion; they then find their way to the bone and start to grow and produce more cells.
Rather than destroying the patient’s bone marrow, just tamp it down enough to make space for the donated marrow to squeeze in alongside and a sort of twin immune system takes root. It’s what doctors taking a page from mythology call “mixed-cell chimerism” — patient and donor blood and immune cells living together to improve health.
The new bone marrow transplant method can be used for many diseases including sickle cell, leukemia and other deadly cancers and metabolic disorders. It’s thought donor matches will not need to be as close as they were before.