Stem cell transplantation, or bone marrow transplantation as a more well-known name, is the method of providing healthy cells instead of bone marrow stem cells, which could not be performed or which produce abnormal cells, or to prevent damage due to high dose chemotherapy after a series of processes by transferring healthy stem cells collected from the patient himself or from a tissue group compatible donor. Firstly the shape and the transmitter of the stem cell must be determined for the procedure. For this decision, the method to be used is chosen according to the requirements and probabilities. If an allogeneic transplant is decided to be the best choice for the receiver, a transmitter must be present. In order to achieve a successful transfer, the genetic coding of the tissue groups of the donor should be as similar as possible to the patient's own tissue. Maximum one mismatch is allowed in this match. For cord blood, there may be two mismatches.
Transport Types and Methods
Bone marrow transplantation:Bone marrow is collected in a blood bag containing substances that prevent coagulation, from the hipbone by two specialist physicians with a needle and syringe under general or local anesthesia and sterile conditions, as is also used in conventional diagnostic methods. This method of collection is the same in all three types of bone marrow transplantation (autologous, syngeneic, allogeneic).
Transfer with Stem Cells in Circulating Environmental Blood:In case that the stem cells in the bone marrow are administered with a special drug (growth factor) and/or collected from the patient, they are stimulated by chemotherapy and collected from the bloodstream by a process called 'apheresis' and delivered to the patient. In the 'apheresis' process, blood is dissociated and collected in the apheresis device while the stem cells are separated and the remaining part of the blood is returned to the patient or donor.
Cord Blood Stem Cell Transplantation:Blood in the umbilical cord of newborns is rich in stem cells and yet the immune cells are not fully immature. These cells can also be collected from the placenta during delivery and they can be used for a patient who needs and has tissue compliance in the future. Collection of the cord blood does not affect the normal birth process or the baby in any way.
Autologous Transfer:It is the transplantation of its own stem cells that were previously collected and frozen. It is used as support treatment in patients who will be administered with high-dose of chemotherapy.
Allogeneic Transfer:The tissue group collected from another person, regardless of whether he/she is a relative of the patient, is the transplantation of fully compatible stem cells. Several subgroups can be mentioned for this application.
Transfer from Siblings with Compatible Tissue Group:It is the form of transmission in which the most successful results are obtained. However, the compliance rate of the siblings is around 25%. In chronic diseases, an IVF method called "preimplantation" can be used to provide disease-free and sibling donors with compatible tissue group.
Syngeneic Transfer:Stem cell transplantation from the patient's twin, if applicable. It may be useful in chronic diseases.
Transfer from non-relative Donors with Compatible Tissue Group:This application is a form of transport from donors provided from the bone marrow bank in the generally known manner. Approximately 26 million volunteer donors in the world are scanned to provide appropriate donors.
Haploidentic Transport:This is the transfer from the first degree relatives of the patient with semi-compliance. It is a popular method in recent years. There are several application methods in this. It can be used in cases where there is no other donor and requires rapid approach.
The First Stage of Treatment
In the first stage, the patient, whose health profile is examined in details and decided to be ready, is treated with chemotherapy and/or radiotherapy called 'preparation regimen' in order to remove the extracellular cells in the bone marrow and not to reject the new cells. Following this, the stem cells collected from the patient or collected from the healthy donor beforehand are given to the patient. The delivery is carried out in a manner similar to the delivery of blood and blood products via a catheter placed in the main vessels. This process is not an operation. Stem cells are immediately directed to the bone marrow after a short circulation in the body to produce new blood cells and begin to restructure the immune system.
The next 1-2 months is the intensive care period. The bone marrow cells that are prepared for the bone marrow transplantation are checked and they are expected to multiply after transferring to the appropriate places in services with airflow filters where specially equipped health personnel work. In this process, the patient whose immune system is completely disabled is susceptible to all infections and many important side effects (Graft-versus-host disease, Veno-occlusive disease, hemorrhagic cystitis, etc.) can be observed.
Adaptation to Life after Treatment
Patients who successfully complete this process are sent home, but this does not mean that everything is over. For one or two years, infections which may be caused by the immune system and not yet fully recovered, serious side effects, sociocultural and psychological problems, education, immunization and so on. may be encountered in the patient. In this process, the patients can be closely monitored and all problems are detected and treated. In addition, the necessary support is provided to the patients to return to their normal lives.