Marrow may be the only hope

Bone marrow's the factory that makes blood. It's also where all kinds of mistakes can be fixed. It may even cure some people who have cancer, aplastic anemia or other life-limiting conditions. Manipulation or replacement of marrow may combat auto-immune disorders like multiple sclerosis or rheumatoid arthritis or fix genetic metabolic defects.

Bone marrow transplants are sometimes a last resort. They're often the only hope.

Blood stem cells provide the magic. Other transplant sources include umbilical cord blood and peripheral blood stem cells.

Dr. Julie Asch, associate director of the marrow transplant program at LDS Hospital, warns that such a transplant does not always work, and it is always risky. But when it succeeds — and there are 20,000 bone marrow transplant survivors who have five years behind them in the United States — they seem like a miracle. Even among the sickest patients, most will survive the actual transplant, although they may not survive the condition for which they've been treated.

Without the National Marrow Donor Registry, most people would never find a suitable marrow match. It contains information on 5 million potential donors; the odds are 1 in 50,000 one of your friends will match. A match is less likely for ethnic individuals, because there are not many in the registry. A full-blood brother or sister has a 1-in-4 chance of matching.

You may be your own best match, depending on why you need a transplant. Self-donation, called autologous, is most often used when cancer responds to chemotherapy. Some of the patient's stem cells are removed, then the patient receives even stronger doses of chemotherapy (which kill marrow, along with the cancer). Then the stored marrow is returned. It requires functioning stem cells to do the job, though.

With self-donation, doctors may collect enough stem cells for as many as three transplants, before allowing the rest of the marrow to be destroyed.

When someone else donates the stem cells, it's called allogeneic rescue. Often it works because the T cells in the donor marrow recognize the cancer and go after it, where the patient's own marrow didn't.

Being your own donor is usually less toxic, but there's a bigger chance of relapse.