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BONE MARROW TRANSPLANTATION

Why is Bone Marrow Transplantation being performed ?

There are two main reasons why bone marrow transplantation (BMT) may be performed. The first is when a patient is lacking in something which can be replaced by giving them normal bone marrow. One example of this is aplastic anaemia, when the patient's own bone marrow disappears, and so he or she cannot produce blood cells. Another example is in children with rare inherited bone marrow disorders. In both cases the cells which are lacking can be replaced by BMT. The second reason for BMT is that it allows doctors to give very intensive treatment to patients with various types of cancer, including leukaemia. The dose of treatment which can normally be given for these conditions is limited because anti-cancer drugs and radiotherapy also affect normal bone marrow cells.

If a transplant is available, then it does not matter if the treatment wipes out the patient's normal marrow completely. The patient can then be given a healthy bone marrow which will replace his or her own marrow. This is the commonest reason for BMT to be performed. People's organs (like bone marrow) have what is called tissue types . These types are distinctive like blood groups for each individual. BMT from another person (allogeneic BMT) is only possible if the patient has a donor of the same tissue type in the family. Unrelated donors of the same tissue type may be used but this procedure has more risks because the marrow will not be as closely matched as if it came from a family donor. Bone marrow can also be taken from the patient himself before treatment and frozen. After the necessary intensive treatment has been completed, the marrow is thawed and given back to the patient. This is called autologous BMT (or autograft). It is especially suitable for patients with cancer which does not involve the bone marrow. It may also help patients with leukaemia who do not have a bone marrow donor. Because of the intensity of the treatment, however, BMT is not suitable for older patients; allogeneic BMT is usually performed up to the age of 55 years and autologous BMT up to the age of 65 years.

Preparations needed for Bone Marrow Transplantation

The most important part of preparation is to become as fully informed as possible about BMT. The decision to recommend BMT for any patient is only made after very careful consideration. You and your family will need to discuss the benefits and risks of BMT very fully with your doctor. You will usually be referred to a transplant centre for assessment and further discussion. There are also some practical points in preparing for BMT. These include planning for a long stay in hospital, making sure that the patient is as fit as possible, and treating any possible sources of infection. For example, teeth should be checked and any decay treated. The transplant centre will advise on this.

What Happens during Bone Marrow Transplantation

ALLOGENEIC BMT is a complicated procedure : your body is to be treated with someone elses marrow. First of all, drugs are given which suppress the body's immunity. This will allow the transplant to be accepted. In the case of BMT for cancer or leukaemia, extra drugs (with or without radiotherapy) are given to kill the malignant cells. The bone marrow is then collected from the donor. It is sucked out of their hip bones under general anaesthetic and collected in a bag. (Additional details are always provided for donors by the doctors performing the transplant.) Later the marrow is then given to you, the recipient, by a drip just like a blood transfusion. The bone marrow cells find their way to your marrow and grow there. You should be able to leave the hospital about 6 weeks after the transplant. However, treatment with drugs to dampen down immunity has to be continued for several months. This is to stop your body from rejecting the marrow, and to stop the cells of the new bone marrow from reacting against you.

AUTOLOGOUS BMT is a more straightforward treatment. There is no need to suppress immunity when your own cells are used for transplant. The bone marrow is collected and frozen. Alternatively, special cells (called stem cells) can be collected from the bloodstream using a machine called a cell separator. After intensive treatment has been given, the bone marrow or stem cells are thawed and given back through a drip. Stem cells have the ability to develop into normal bone marrow cells. MINI-GRAFTS. This is a new treatment in which the donor bone marrow cells help to destroy the abnormal leukaemia cells. Less intensive preparation is needed for this type of transplant.

Possible Complications of Bone Marrow Transplantation

ALLOGENEIC BMT The possible complications can be divided into three main groups. First of all, the treatment is very intensive. There is a risk of damage to organs other than the marrow, for example the liver and the kidneys. The recipient's own marrow disappears. Until the transplanted marrow grows, you will not be able to make red cells which carry oxygen, white cells which fight infection, or platelets which prevent bleeding. Transfusions of red cells and platelets are given regularly, but transfusions of white cells are not practicable. There is therefore a risk of infection at this time. You will be nursed in protective isolation (in a single room, usually with staff and visitors wearing gowns or aprons). Even so, and with modern antibiotics, serious infection can occur. The second main risk is of graft-versus-host disease (GVH). This is due to white blood cells called lymphocytes in the donor marrow recognizing the patient's cells as foreign and attacking them. It affects the skin, the liver, and the bowel. In spite of drugs for preventing and treating GVH, serious GVH can still occur. The third main risk is that of unusual infections, usually occurring after discharge from hospital. These are due to the long time taken for the new immune system to become established. Infection is also a risk from the immunosuppressive drugs used to prevent rejection and GVH. A particular problem is a virus called cytomegalovirus (CMV). This is similar to the virus causing glandular fever. In normal people it causes a mild illness, but in BMT patients it can be very serious. There is therefore a risk of serious complications after BMT, and these can sometimes be fatal. AUTOLOGOUS BMT In this case, complications such as infection can occur during the first few weeks, but once the marrow cells have grown back, complications are very unusual. Normal immunity recovers quickly and there is no risk of GVH.

After Bone Marrow Transplantation

One should look on BMT as a very major operation. It will take several months to get back to normal and patients need to make frequent visits to hospital for check-ups. Various drugs need to be taken for several months. These include immunosuppressive treatment and antibiotics to prevent infection. One cannot plan to return to school or work until about 6 months after BMT.

If Bone Marrow Transplantation is not performed

Because of the risks of BMT, it is only recommended for patients who have a serious disease where other treatments are likely to be ineffective.

Effects on Family of Bone Marrow Transplantation

You will need extra care and support both physical and psychological during and after the transplant. Visitors are allowed even during the time the patient is in protective isolation, and many centres will encourage a close relative or friend to be with you for most of the time.