Hematopoietic Stem Cell Transplantation (HSCT)
Update : October 14, 2015
Nowadays, there are a lot of diseases that does not respond to treatments, not just cancer. They are called elapsed or refractory diseases. Bone marrow disorder for once is an example of these diseases. The most common bone marrow disorders are bone marrow disease scare (bone marrow failure), Anemia Thalassemia, and some genetic diseases. With this knowledge and understanding of the principles upheld by the plant, stem cells are crucial to pediatricians who are involved in patient care. Accurate information about stem cell transplantation to patients who are kids needs to be explained carefully to their parents, referral during the fair period and providing care to patients after transplantation of stem cells.
Elements of Stem Cell Transplantation
Stem cell transplantation treatment consists of three elements.
- Host or recipient-refers to those who received stem cells or the patient
- Donor- refers to the one who gives his/her stem cell for the patient. He/she may be another person or may be a victim himself.
- Conditioning regimen- refers to the way we prepare the patient so that the patient is ready to receive a transplant of stem cells.
Types of Stem Cell Transplantation
In general, the transplanted stem cells can be divided into two categories:
- Autologous HSCT -stem cell transplant using stem cells themselves (donor and recipient are the same person), the stem cells are collected from the patient before. It may be collected from bone marrow or from his blood. Then the stem cells are frozen and it is brought to the patient after the patient has received high-dose chemotherapy. High-dose chemotherapy destroys the cells in the bone marrow and the remaining cells do not grow up to be new. For this reason, the patient’s own stem cell is introduced back to him/her. These stem cells are back into the patient's bone marrow and grow then develop into cells to work normally.
- Allogeneic HSCT is a stem cell transplant using stem cells from others. The most likely cause of the patient's disease is a disorder of the blood or bone marrow. Thus, the transplanted stem cells eliminate the blood cells and bone marrow disorders. It takes stem cells from a healthy donor to transplant them.
However, the donor 's stem cells and the patient must have human leukocyte antigen (HLA) compatible. The brother will have the opportunity to have the same HLA matched one out of four, or 25 % of siblings (related donor).
Donors may be those who register their intention to donate stem cells (unrelated donor) or possibly the placenta and umbilical cord blood donors for the treatment of patients (cord blood donor).
Sources of Stem Cell Transplantation
Stem cells can be collected from three different sources.
- Bone marrow. The procedure penetrates the bone marrow from a donor.
- Posterior iliac crest on both sides of the patient is drilled after general anesthesia in the operating room. The bone marrow is then drilled out to get 20 mL per body weight of the recipient. Heparin is then used as a preservative to avoid blood clotting.
- Blood (peripheral blood). Peripheral blood is mainly collected from donors who are older child or adult. The donors were injected growth factor (G-CSF) for 4-5 days prior donating to stimulate hematopoietic stem cells out from the bone marrow into the bloodstream. Then, white blood cells from the donor’s blood are separated using automated cell separator machine.
- Blood from the umbilical cord. Collection is done in the delivery room with infection precaution as much as possible by using a needle or catheter inserted into the umbilical vein immediately after birth then the umbilical cord will be cut off. The cord’s blood flows down by gravity directly through the storage bag. Umbilical cord blood can be stored for about 60-140 mL. It will be frozen until the time that it will be used.
Complications of Stem Cell Transplantation
- Graft rejection: This condition can be from the recipient’s immune cells which still remain after conditioning regimen. This is common in patients with a history of multiple blood transfusions prior to stem cell transplantation and develops an antibody to donor stem cells. This can be treated by a donor lymphocyte infusion (DLI) in the case found that the number of donor cell decline or may have to make a new conditioning regimen again, followed by the second stem cell transplantation.
Graft-versus-host disease (GvHD) This condition results if the T-cell in the bone marrow of the donor attacks recipient’s body. The symptoms can be from mild skin rash to severe illness causing death. This condition is a major problem that hinders the success of the transplantation of stem cells. Because of this, the patient needs to receive high-dose immunosuppressant after stem cell transplantation.
The immune system of the recipient has been destroyed and cannot eliminate the mixed T-cell in the bone marrow from the donor T-cell which is activated by antigen on the surface of cells. As a result, the body's T-cell receptors are stimulated. GvHD can be divided into two types: acute and chronic, acute GvHD usually occurs within 100 days post stem cell transplantation. The involved organs include skin, liver and gastrointestinal tract. Chronic GvHD often occurs after 100 days. In some cases it may be faster by 40-50 days after transplantation especially those who have skin disease (scleroderma), anorexia, or chronic hepatitis. Side effects may include weight loss, dry mouth due to reduced saliva build-up, and dry eyes. Dry eye associated with GvHD can be achieved by using drugs such as corticosteroid or other immunosuppressive kind.
- Infection is a complication where Patients are at most risk to develop after transplantation of stem cells.
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