An autologous transplant is also called a self stem cell transplant. This means that a person is their own stem cell donor, and the stem cells that are transferred to replace damaged or destroyed stem cells will have come from their own body.
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Why are Autologous Transplants Needed?
Autologous transplants are used in the treatment of several different cancers, such as leukemia, lymphoma, multiple myeloma, and sometimes testicular cancer and neuroblastoma. Some cancers that develop in children can also be treated with autologous transplants.
An autologous transplant may be needed for people who require high-dose anti-cancer treatment, which kills cancer cells but also kills the stem cells in the bone marrow that produce new blood cells. Having an autologous transplant will replace the stem cells lost during high-dose anti-cancer treatments so that the bone marrow can produce new blood cells again.
Autologous transplants can also be used to treat non-cancerous diseases, such as systemic sclerosis, multiple sclerosis (MS), and systemic lupus erythematosis.
The Autologous Transplant Procedure
The autologous transplant process takes a long time and requires a long recovery period that can last for a year. Although the treatment will be done in one or several days, a person may stay in the hospital for a few weeks after their transplant.
It takes 2 to 3 weeks for a blood count to recover after an autologous transplant. However, although a person’s blood counts may return to normal in 3 weeks, their immune system will still be weakened from the chemotherapy treatment used in an autologous transplant.
The procedure includes harvesting the stem cells from the person who requires an autologous transplant. The stem cells will be removed from the bone marrow or bloodstream before being frozen until they are needed for the transplant.
Before the stem cells are harvested, a medication called filgrastim is given to increase the number of stem cells being produced. Filgrastim can cause flu-like symptoms and aches and pains. Another drug may also be used to encourage the stem cells to move from the bone marrow to the bloodstream, and chemotherapy medication can also be used for this purpose in autologous transplants.
Most transplants will use stem cells taken from the bloodstream, which are called peripheral blood stem cells (PBSC). This is because stem cells are easier to harvest from the blood than from the bone marrow.
Peripheral blood stem cell harvesting
For autologous transplants that take stem cells from the blood, the process is similar to typical blood donation and does not require an operation or the use of general anesthetic. It can take three to four hours to harvest cells, and several appointments may be needed to collect enough cells for the transplant.
A thin needle connected to a tube will be inserted into a vein in each arm. Blood will be drawn out from the veins and passed through a machine that separates the blood from the stem cells in a process called apheresis. The remaining blood is returned to the body through the vein in the opposite arm.
Bone marrow stem cell harvesting
For autologous transplants that use stem cells from the bone marrow, an operation and general anesthetic will be used. A needle is inserted into the rear pelvic bone and the bone marrow is extracted with a syringe. The procedure takes around 1 to 2 hours.
More than one bone marrow harvest is needed to collect enough bone marrow for an autologous transplant, and 1 to 2 quarts of bone marrow is usually needed for a transplant, although it depends on the weight of the person undergoing the transplant.
This procedure may cause bruising, pain, and aching in the lower hip area and may become worse with prolonged sitting or climbing stairs. This can be relieved with painkillers and anti-inflammatories.
The body will replace the harvested bone marrow cells within 4 to 6 weeks.
After the cells have been harvested either from the bone marrow or the bloodstream, a person will undergo chemotherapy treatment for their cancer. They will then have their stem cells thawed and reintroduced into the body through a transplant to replace those lost in chemotherapy.
Tandem Autologous Transplants
A tandem autologous transplant, also called a double autologous transplant, means a person has two autologous transplants in a row. A person would be given two doses of high-dose anti-cancer treatment, with an autologous transplant after each chemotherapy treatment.
For tandem autologous transplants, all of the stem cells needed for both transplants will be collected before the person has any chemotherapy treatment. Half of the stem cells are used for each transplant after chemotherapy treatment. The chemotherapy treatments are usually given over 6 months, and the second round of chemotherapy is given after the person has recovered from their first round of treatment.
Tandem transplants can include one autologous transplant and one allogenic transplant.
The Benefits of Autologous Transplants
A person who is their own stem cell donor will not have to worry about their body rejecting the stem cells once they are transferred back into their body. With allogeneic transplants, in which a person donates stem cells to another person, there is a risk that the body will reject the stem cells.
There is no risk of graft-versus-host disease (GVHD) with autologous transplants. GVHD is a potentially serious complication that can occur after allogeneic transplants, in which the donated stem cells attack healthy cells, which can cause mild to life-threatening symptoms.
The Risks of Autologous Transplants
In autologous transplants, there is a risk that the transplanted stem cells will not enter the bone marrow and begin to make new blood cells. In patients with cancer, it may not be possible for the body to produce enough stem cells for a harvest to take place.
There is also a risk that cancer cells will be collected with the stem cells and be transplanted back into the body. However, to lower the risk of this happening, stem cells can be treated in a process called purging before they are transplanted back into a person. There is only a small number of studies investigating the efficacy of the purging process, so its effectiveness cannot be fully determined.
Additionally, some stem cells can be lost in this process, reducing the number of stem cells that are transplanted into the person. This may mean that the body takes longer to begin producing new blood cells after treatment.
During stem cell harvests, as with any procedure that includes breaking the skin with a needle, there is a risk of infection at the site where the blood is drawn. Blood clots are also a risk of stem cell harvesting.
After apheresis, a person may experience low calcium levels and associated problems caused by a drug used to keep the blood from clotting in the apheresis machine. Symptoms of this can include light-headedness, chills, and muscle cramps. Calcium supplements can be given to relieve these symptoms.
Autologous transplants do not offer the benefits of the graft vs tumor (GVL) effect. The GVL effect is when the donated stem cells attack any remaining cancer cells after chemotherapy treatment. There is a higher risk of relapse with autologous transplants.
Summary
An autologous transplant is a type of stem cell transplant used in the treatment of certain cancers and some other, non-cancerous diseases. An autologous transplant is used to replace stem cells lost during chemotherapy treatment, which helps the body to make new blood cells again.
As harvesting stem cells include medical procedures, sometimes involving general anesthetic, there is a risk of infection at the site of the procedure, as well as a risk of blood clotting.
Although autologous transplants do carry a higher risk of a person’s cancer returning, there is more chance that a person’s body will not reject the transplanted stem cells, and there is no risk of graft-versus-host disease, which can be a serious complication.
Further Reading