blood and marrow stem cell transplant
Stem cells are found in bone marrow – a sponge-like tissue inside the bones. Stem cells develop into the three types of blood cells that the body needs:
Another type of stem cell, called an embryonic stem cell, can develop into any type of cell in the body. These cells aren't found in bone marrow.
OverviewDoctors use stem cell transplants to treat people who have:
Types of transplantsTwo main types of stem cell transplants are autologous and allogenic.
For an autologous transplant, a person's own stem cells are collected and stored for use later on. This works best when a person still has enough healthy stem cells even though he or she is sick. For a person with cancer, doctors also make sure that cancer cells are removed or destroyed from the collected cells.
For an allogenic transplant, a person gets stem cells from a donor. The donor can be a relative (like a brother or sister) or an unrelated person. A person also may get stem cells from umbilical cord blood donated by an unrelated person.
To prevent problems, the donor's stem cells should match the recipient's as closely as possible. Donors and recipients are matched through a blood test called HLA tissue typing.
Collection processStem cells used in transplants are collected from donors in several ways. They can be collected:
OutlookStem cell transplants have serious risks. Some complications are life threatening. For some people, however, a stem cell transplant is the best hope for a cure or a longer life.
Who needs a blood and marrow stem cell transplant?You may need a blood and marrow stem cell transplant if you have a disease or condition that prevents your body from making enough healthy blood cells.
These diseases and conditions include:
When deciding whether you need a stem cell transplant, your doctors will consider:
What to expect before a blood and marrow stem cell transplant
Finding a donorIf you're going to receive stem cells from another person, your doctors will want to find a donor whose stem cells match yours as closely as possible.
A close match can reduce the risk that your immune system will attack the donor cells. It also reduces the risk that cells from the donor's marrow or blood will attack your body.
HLA tissue typingPeople having transplants are matched with donors through a test called HLA tissue typing. HLAs are proteins found on the surface of white blood cells. Your immune system uses HLAs to tell which cells belong to you and which don't.
Because HLA markers are inherited, an identical twin is the best donor match. Brothers or sisters also can be good matches. However, many people don't have a good match within their families.
If no matching donor is found in your family, the search widens to include people outside the family. Millions of volunteer donors are registered with the National Marrow Donor Program. Your doctors will look for:
Medical tests and examsYou also will need other medical tests and exams before a stem cell transplant. Your doctors will want to make sure you're healthy enough to have a transplant. They also want to find out whether you have any medical problems that could cause complications after the transplant.
Blood tests are used to check for HIV, herpes, pregnancy, and other conditions. These tests help doctors learn about your overall health.
Chest X-ray and lung function tests
A chest X-ray provides a picture of your heart and lungs. It can show whether the heart is enlarged or whether the lungs have extra blood flow or extra fluid.
Lung function tests tell doctors whether you have any lung infection or disease. They also show how well your blood is able to carry oxygen through your body.
Computed tomography scan, skeletal X-ray, or bone scan
Computed tomography (CT) scans, skeletal X-rays, and bone scans provide detailed images of the body. They're used to see whether you have any tumors in your bones that might cause a problem for a transplant.
A complete dental exam is used to check for problems that might cause an infection after your transplant.
Heart tests, including EKG (electrocardiogram) and echocardiography, are used to find any conditions that might get worse after the transplant.
An EKG detects and records the electrical activity of your heart. Echocardiography uses sound waves to create a moving picture of your heart. The picture shows how well your heart is working and its size and shape.
Bone marrow biopsy
A bone marrow biopsy helps show whether your bone marrow is making enough healthy blood cells. If you're being treated for a blood cancer, this test shows whether your cancer is inactive.
What to expect during a blood and marrow stem cell transplantA blood and marrow stem cell transplant has three parts: preparation, transplant, and recovery in the hospital.
PreparationYou will check in to the hospital a few days before the transplant. Using a simple surgical procedure, doctors will place a tube in a large vein in your chest. This tube is called a central venous catheter, or a central line. It allows easy access to your bloodstream.
Doctors use the central line to give you fluids, medicines, and blood products and to collect blood samples. The tube will stay in place for at least 6 months after your transplant.
To prepare your body for the transplant, your doctors will give you high doses of chemotherapy and possibly radiation. This treatment destroys the stem cells in your bone marrow that aren't working properly. It also suppresses your body's immune system so that it won't attack the new stem cells after the transplant.
The high doses of chemotherapy and radiation can cause side effects, including nausea (feeling sick to your stomach), vomiting, diarrhea, and tiredness. Medicines can help with these symptoms.
In older patients or those who aren't very strong, doctors may choose "reduced-intensity" treatment. This involves lower doses of chemotherapy or radiation.
Because your immune system is very weak after this treatment, you can easily get an infection. As a result, you will stay in a hospital room that has special features that keep the room as clean as possible.
Doctors, nurses, and visitors also have to wash their hands carefully and follow other procedures to make sure you don't get an infection. For example, they may wear a face mask while in contact with you.
Preparation before a transplant may take up to 10 days. The time depends on your medical situation, general health, and whether you need chemotherapy or chemotherapy and radiation.
TransplantDuring the transplant, which is like a blood transfusion, you get donated stem cells through your central line. Once the stem cells are in your body, they travel to your bone marrow and begin making new red blood cells, white blood cells, and platelets.
You're awake during the transplant. You may get medicine to help you stay calm and relaxed. Doctors and nurses will check your blood pressure, breathing, and pulse, and watch for signs of fever or chills. Side effects of the transplant can include headache or nausea – but you may not have side effects.
The transplant takes an hour or more. This includes the time to set up the procedure, the transplant itself, and time to check you afterward.
Recovery in the hospitalYou will stay in the hospital for weeks or even months after your stem cell transplant. In the first few days after the procedure, your blood cell levels will continue to go down. This is because of the chemotherapy or radiation you got before the transplant.
Your doctors will test your blood 7 to 10 days after the transplant to see whether new blood cells have begun to grow. They will check your blood counts every day to track your progress.
You will stay in the hospital until your immune system recovers and doctors are sure that your transplant was successful. During your time in the hospital, your doctors and nurses will carefully watch you for side effects from chemotherapy and radiation, infection, and graft-versus-host disease (GVHD) and graft failure.
Side effects from chemotherapy or radiation
The chemotherapy and possible radiation you get before the transplant have side effects. These side effects begin to appear a few days after the transplant. Some of these side effects are painful or uncomfortable; others are very serious. They include:
You can easily get an infection after the transplant because your immune system is weak. Some infections are serious. Infections can be caused by:
You also can take other steps to prevent infections.
Graft-versus-host disease and graft failure
Donated stem cells can attack your body. This is called graft-versus-host disease. Your immune system also can attack the donated stem cells. This is called graft failure. These events can be minor or life threatening. They can happen soon after transplant or can develop slowly over months.
What to expect after a blood and marrow stem cell transplantYou will stay in the hospital for weeks or even months after your blood and marrow stem cell transplant. Your doctors want to be sure that you're healthy and strong enough to go home.
They want to make sure:
Staff at the clinic will teach you and your caregiver how to care for your central line, how to watch for and prevent infections, and other ways to care for you. They also will tell you who to call and what to do in case of emergency.
Recovery from a stem cell transplant can be slow. It takes 6 to 12 months to recover normal blood cell levels and immune function. During this time, it's important for you to take steps to reduce risk of infection, get plenty of rest, and follow your doctors' instructions about medicines and checkups.
What are the risks of a blood and marrow stem cell transplant?The main risks of a blood and marrow stem cell transplant are infection, graft-versus-host disease (GVHD), and graft failure.
InfectionYou can easily get an infection after the transplant because your immune system is weak. The risk for infection decreases as your immune system recovers.
You can take steps to prevent infections, such as washing your hands and staying away from crowds. Doctors use medicines to prevent and treat infections.
Graft-versus-host diseaseGVHD is a common complication if you receive stem cells from a donor. In GVHD, the new stem cells attack your body.
Acute GVHD occurs within 90 to 100 days after the transplant. Chronic GVHD begins more than 90 to 100 days after the transplant or goes beyond 90 days after the transplant.
GVHD can be minor or life threatening. Signs and symptoms include:
Chronic GVHD is treated with steroids – usually cyclosporine and prednisone on alternating days.
Older people, people who have had acute GVHD before, and people who received stem cells from mismatched or unrelated donors are more likely to develop GVHD.
Doctors can reduce your chances of getting GVHD by:
Graft failureGraft failure occurs when your immune system rejects the new stem cells. It also can occur if not enough stem cells are used, the new stem cells are damaged during storage, or your bone marrow is damaged after the transplant.
Graft failure is more likely in people who receive less preparation for their transplants. People who get stem cells from a poorly matched donor also are more likely to have graft failure.
Other risksComplications from chemotherapy and radiation treatment (used to prepare for a transplant) can occur long after a transplant. These complications include infertility, cataracts, new cancers, and damage to the liver, kidneys, lungs, or heart.
Related category• HEALTH AND DISEASE
Source: U.S. National Heart, Lung and Blood Institute
Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact