BONE MARROW AND STEM CELL TRANSPLANTATION

How is a bone marrow transplant done?
Bone marrow produces blood cells. Stem cells are immature cells found in the bone marrow that make up all the different blood cells. Hematopoietic stem cells are used in transplants. Stem cells are transferred to the patient (the recipient) via the vascular access. Intravenous devices called central venous catheters are used for this purpose. After transplantation, immature cells begin to live in the bone marrow and turn into a variety of mature blood cells, including:

• Oxygen-carrying red blood cells
  • Platelets that help blood clot
  • White blood cells that help fight infection.

With a bone marrow transplant, damaged stem cells are replaced with healthy cells. This helps the body make enough white blood cells, platelets or red blood cells to avoid infections, bleeding disorders or anemia.
There are different types of blood stem cell transplants. The type of transplant depends on the source of blood stem cells.
In bone marrow transplants (BMT), blood stem cells collected from the bone marrow are used.
Peripheral blood stem cell transplants (PBSCT) use blood stem cells collected from the bloodstream.
In cord blood transplants (CBT), blood stem cells collected from the placenta and umbilical cord of a newborn baby are used.

What cells are produced in the bone marrow?
The donor can be discharged after being kept under observation for 24 hours after collection. The collected marrow is passed through special filters in order to separate the fat and small bone fragments that may have been mixed into the marrow. If it is not used immediately, it is frozen by being placed in special liquids. When it is used, it is thawed and given to the patient, similar to a blood transfusion. These blood stem cells, which enter the patient’s body, settle in the bone marrow and begin the production of blood cells usually within 2–4 weeks.

Autologous stem cell transplant
Autologous stem cell transplants use healthy blood stem cells in the body to replace diseased or damaged bone marrow. During a stem cell transplant, using cells from one’s own body has some advantages over using stem cells from someone else. For example, in autologous stem cell transplants, there is no incompatibility problem between the transplanted cells and the body’s own cells.
An autologous bone marrow transplant may be an option only if the body is producing enough healthy bone marrow cells. These cells can be harvested, frozen and stored for later use. Autologous stem cell transplants are frequently used in patients requiring high doses of chemotherapy and radiation. Autologous stem cell transplants help replace damaged bone marrow.
Autologous stem cell transplants are mostly used to treat the following conditions:
• Hodgkin lymphoma
• Myeloma
• Hodgkin’s lymphoma
• Plasma cell disorders.

Allogeneic Stem Cell Transplantation
Allogeneic stem cell transplants use healthy “blood stem cells” from a donor to replace diseased or damaged bone marrow. Allogeneic stem cell transplantation is also referred to as allogeneic bone marrow transplantation.
Donor: It could be a family member, acquaintance or stranger. Cells used in allogeneic stem cell transplantation can be collected from different sites, such as:
• From the donor’s blood,
• From the bone marrow in the donor’s hip bone,
• From donated umbilical cord blood.
Before an allogeneic stem cell transplant is performed, high doses of chemotherapy or radiation therapy are taken to destroy diseased cells and prepare the body for donor cells. An allogeneic steam cell transplant may be an option for people with a variety of diseases, including:
• Acute leukemia
• Adrenoleukodystrophy
• Extreme anemia
• Bone marrow failure syndromes
• Chronic leukemia
• Hemoglobinopathies
• Hodgkin’s lymphoma
• Immune deficiencies
• Congenital metabolic errors
• Multiple myeloma
• Myelodysplastic syndromes
• Neuroblastoma
• Hodgkin’s lymphoma
• Plasma cell disorders
• POEMS syndrome
• Primary amyloidosis.

How are stem cells collected and frozen?

Stem cells are obtained by using special apheresis devices, often from blood taken from veins in the arm or from special catheters that can be inserted into veins in the neck region. Donors are given a drug that is applied subcutaneously twice a day for 4-5 days, which allows the stem cells to go into the surrounding blood. Then, as if the donor were donating blood, it is connected to the apheresis device for 2-4 hours, and the stem cells are collected for 1–2 days. The transmitter does not need to be put to sleep during this process. During the procedure, there may be numbness in the lips and cramps in the arms, but only rarely. There is no risk to the person who wants to be a stem cell donor. We can compare it to donating blood. The donor’s stem cells are replaced in a very short time.
The collected stem cells are counted and either given to the recipient immediately or frozen until delivery. Ice is made at -80 degrees Celsius, and the frozen stem cells continue to live in this state. Stem cells can survive for many years at -196 degrees Celsius. When they will be given to the recipient, the frozen stem cells are thawed, and the product, which is now ready, is given to the patient through a vein in a blood bag. Stem cells delivered to the blood settle in the bone marrow to produce blood cells. Production of blood cells takes place approximately 2–4 weeks after transplantation. Complete recovery of the immune system takes 2-3 months for autologous transplants and 1-2 years for allogeneic transplants.

How is autologous stem cell transplantation done?
In order to destroy the patient’s underlying blood disease, chemotherapy is given first, then drugs are given to prevent the disease from recurring, and the patient’s own stem cells are collected and frozen. After that, the patient is given high-dose chemotherapy, aiming to destroy all the remaining malignant cells. Nausea, vomiting and infections may occur during high-dose treatment. With this treatment, the patient’s own stem cells, previously frozen, are given to the patient to help the bone marrow recover. In this transplant process, the donor’s stem cells are better tolerated than the patient’s own and there are fewer problems.

For autologous stem cell transplantation (multiple myeloma, Hodgkin, and non-Hodgkin lymphoma),
• You must be under the age of 65.
• The patient’s performance should be good.
• The heart’s ejection fraction should be greater than 50%,
• Liver function tests should not be impaired more than twice as much as they should be,
• Lung function tests: DLCO should be > 60%.