Allogeneic stem cell transplant

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Most stem cells are located in the bone marrow, and some run from bone to blood. Bone marrow stem cells turn into red cells, white blood cells or platelets to help maintain healthy body.

If bone marrow is damaged or destroyed, it can’t produce normal blood cells. In this case, you will need a transplant of healthy stem cells to be made through an intravenous line, through which some healthy stem cells will be introduced into the body; this helps the bone marrow begins to function normally.

When stem cells come from another person, the transplantation is called allogeneic. The donor may be a relative or a stranger. The most important is that the immune system markers of the donor must be in correlation with those of the patient. This is most likely when the donor is a brother or sister of the patient. When stem cells come from the patient’s blood or bone marrow, transplant is called autologous. Stem cells can be found in the peripheral blood or umbilical cord of a newborn.


1. Overview
2. Donor identification
3. Why are chemotherapy and radiotherapy done before a transplant?
4. The allogeneic stem cell transplant
5. Mini transplant
6. After transplant
7. Risks

Donor identification

Finding a donor is the main action for the success of allogeneic stem cells transplant. Donor compatibility testing may include the following results:

- HLA – relative compatibility (usually a brother)
- HLA – compatibility without family relationship
- HLA – incompatibility with a family member
- Blood from the umbilical cord.

The donor can often be the brother, sister or other relatives. Often, donors are found depending on the type of tissue compatibility. By HLA test, the doctor compares blood and tissue samples from a donor with the patient.

Excepting the use of stem cells from the blood circulating in the body of a donor, can also be used blood cells from the umbilical cord. Stem cells found in umbilical cord blood are less mature, which means they have the potential to differentiate into different cell types.

By cryogenisation held after being harvested, they avoid damage the environment and the aging process. Umbilical cord blood transplants do not involve compatible tissue testing and can help reduce the risk of complications.

Why are chemotherapy and radiotherapy done before a transplant?

Through chemotherapy and radiation, doctors destroy bone marrow. In this way cancer is removed from the affected cells, but there are also destroyed normal cells too – the bone marrow of the body. Later, when healthy stem cells will be transferred from a donor, they will reach the bone marrow and it will take over to produce new blood cells.

The allogeneic stem cell transplant

Before allogeneic stem cell transplant, is undergoing intensive treatment to destroy as many cancer cells as possible. It will be either chemotherapy or chemotherapy and radiotherapy. Once this step is complete, you will be ready for transplant. Transplantation will be done approximately 20 days after intensive treatment was complete. Patient receives stem cells, as a blood infusion, intravenously. The procedure takes about an hour.

After they have entered the bloodstream, stem cells circulate by the bone marrow and begin producing new blood cells during a process known as grafting. Transplantation restores normal amount of cells that were destroyed by intensive therapy.

Mini transplant

A mini transplant is a type of allogeneic transplant that uses lower doses, less toxic chemotherapy and / or the total body irradiation before transplantation.

The use of lower doses of anticancer drugs and a lower level of total radiation on the body remove a fairly large amount of bone marrow. The patient’s immune system is suppressed to prevent graft rejection.

Once the donor bone marrow cells are transplanted, they can cause graft effect against the tumor and may act to destroy cancer cells that have already been removed with anticancer drugs and radiation on the body.

After transplant

Hematologic oncology team will work in an attempt to reduce complications and risks to meet patient needs throughout the process of stem cell transplantation. Since the immune system needs time to consolidate, doctors will monitor the patient closely in the months following the transplant.

Sometimes high doses of chemotherapy and radiation, received before the transplant can cause side effects such as infection. Doctors will constantly do blood tests and can do a blood transfusion to prevent or treat infections or bleeding problems.

Another risk of allogeneic stem cell transplantation is graft versus host disease, a condition in which donor cells attack the tissues of the patient. Reduced incompatibility between patient and donor increases the risk triggering the disease. Your doctor may prescribe certain medications to reduce the risk of triggering infection or graft versus host disease.


Early complications may occur in 5-10 days and include:

- sores in the mouth
- hair loss
- bleeding due to severe reduction in the number of red blood cells, white blood cells and platelets
- nausea and vomiting
- diarrhea
- infections such as pneumonia, shingles, herpes simplex

Other possible complications include:

- depression
- infertility
- cataract
- complications of lung, kidney and heart
- recurrence of disease for which transplantation was done, in order to treat it
- other cancer types.

Serious long-term complications include:

- graft failure – new stem cells work a short time and then fails. If this happens healing possibilities are low.
- graft versus host disease
- hepatic veno-occlusive disease
- infections.



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