A blood and marrow stem cell transplant is a procedure that replaces a person's faulty stem cells with healthy ones.
Stem cells are found in bone marrow, a spongy tissue inside the bones. Stem cells develop into the three types of blood cells that the body needs:
Small numbers of stem cells also are found in the blood and in the umbilical cord (the cord that connects a fetus to its mother's placenta).
Another type of stem cell, called an embryonic (em-bre-ON-ik) stem cell, can develop into any type of cell in the body. These cells aren't found in bone marrow.
Doctors use stem cell transplants to treat people who have:
The two main types of stem cell transplants are autologous (aw-TOL-o-gus) and allogenic (a-LO-jen-ik).
For an autologous transplant, your own stem cells are collected and stored for use later on. This works best when you still have enough healthy stem cells, even though you're sick. If you have cancer, the cancer cells are removed or destroyed from the collected cells.
For an allogenic transplant, you get stem cells from a donor. The donor can be a relative (like a brother or sister) or an unrelated person. You also may get stem cells from umbilical cord blood donated by an unrelated person.
To prevent problems, the donor's stem cells should match yours as closely as possible. Donors and recipients are matched through a blood test called HLA tissue typing.
The stem cells used in transplants are collected from donors in several ways.
A procedure called apheresis (a-fer-E-sis) may be used. For this procedure, a needle is placed in the donor's arm to draw blood. Then, his or her blood is passed through a machine that removes the stem cells from the blood. The rest of the blood is returned to the donor.
Stem cells might be collected directly from a donor's pelvis. This procedure isn't used very much anymore because it must be done in a hospital using local or general anesthesia (AN-es-THE-ze-ah). For this procedure, a hollow needle is inserted repeatedly into the pelvis, and marrow is sucked out of the bone.
Blood containing stem cells may be collected from an umbilical cord and placenta after a baby is born. The blood is frozen and stored at a cord blood bank for future use.
Stem cell transplants have serious risks. Some complications are life threatening. For some people, however, stem cell transplants are the best hope for a cure or a longer life.
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Blood and Marrow Stem Cell Transplant, visit www.clinicaltrials.gov.
December 9, 2013
Gary H. Gibbons
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