A bone marrow transplant is when special cells (called stem cells) that are normally found in the bone marrow are taken out, filtered, and given back either to the same person or to another person.

In diseases such as leukemia and aplastic anemia, the bone marrow is unhealthy. The purpose of a bone marrow transplant is to replace unhealthy stem cells withhealthy ones. This can treat or even cure the disease.

If a family member does not match the recipient, the National Marrow Donor Program Registry database can be searched for an unrelated individual whose tissue type is a close match. It is more likely that a donor who comes from the same racial or ethnic group as the recipient will have the same tissue traits. The chances of a minority person in the United States finding a registry match are lower than that of a white person (see article, Marrow Matches For Minorities Are Harder to Find).

If stem cells are collected by bone marrow harvest (much less likely), the donor will go to the operating room and while asleep under anesthesia, a needle will be inserted into either the hip or the breastbone to take out some bone marrow. After awakening, he/she may feel some pain where the needle was inserted.

Serious problems can occur during the time that the bone marrow is gone or very low. Infections are common, as is anemia, and low platelets in the blood can cause dangerous bleeding internally. Recipients often receive blood transfusions to treat these problems while they are waiting for the new stem cells to start growing.

When a person volunteers to be a donor, his/her particular blood tissue traits, as determined by a special blood test (histocompatibility antigen test), are recorded in the Registry. This "tissue typing" is different than a person's A, B, or O blood type. The Registry record also contains contact information for the donor, should a tissue type match be made.

Note: The author has been a registered donor since 1993.

Source:

"The Donation Procedure." Donor Information. Oct 2005. National Marrow Donor Program. 25 Jul 2007.

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Bone Marrow Transplants - How They Work - About.com Rare Diseases