Bone Marrow Transplantation – Types of Surgical Operations
Bone marrow/hematopoietic stem cell transplantation is an effective method of treating blood system diseases, congenital and acquired immunodeficiency, autoimmune diseases of the nervous system and connective tissue, as well as certain forms of malignant neoplasms in children and adults.
More than 50,000 bone marrow transplants are performed annually in the world. For many patients, transplantation gave a chance to get rid of a terrible disease. Transplantation allows not only to get long-term and stable remissions of the disease, when traditional treatment is powerless, but with a number of diseases to completely recover from a serious illness.
Technology and types of transplantation
The technology of bone marrow transplantation or hematopoietic stem cells of peripheral blood involves intravenous injection into the patient’s body of a previously taken from the donor or the patient himself and a specially treated suspension of bone marrow or hematopoietic stem cells of peripheral blood. Hematopoietic cord blood stem cells are used much less frequently, mainly in children. As a rule, the transplantation is preceded by intensive chemotherapy, the main purpose of which is the maximum reduction of tumor cells and cells of the immune system.
Depending on the source of the transplanted cells , there are:
- Allogeneic transplantation of bone marrow/hematopoietic stem cells of peripheral blood. In this type of transplantation, the source of hematopoietic cells is a healthy person (donor) who has a genetic similarity with the patient (recipient) according to certain genetic parameters. The donor can be related (brother, sister, parents) or unrelated.
- Autologous transplantation of bone marrow/hematopoietic stem cells of peripheral blood — the source of stem cells or bone marrow is the patient himself.
- Syngenic bone marrow/hematopoietic stem cell transplantation of peripheral blood, which is a type of allogeneic transplantation. The donor for syngenic transplantation is a monozygotic (genetically similar) twin of the patient.
Stem cell separator
Autologous transplantation is a type of transplantation in which the patient’s own hematopoietic cells contained in the bone marrow, peripheral or umbilical cord blood are transplanted. Since the mid-70s of the XX century, bone marrow has been used less and less for transplantation, due to the appearance of special equipment for obtaining stem cells from peripheral blood (stem cell separators). Blood cell separators have made the procedure for obtaining hematopoietic stem cells much more efficient and safe.
The resulting product of hematopoietic stem cells (bone marrow, peripheral blood, umbilical cord blood) is frozen and stored for the required time in a liquid nitrogen environment at -197 ° C. Thawed cells are transplanted to the patient by intravenous infusion. As a rule, intensive chemotherapy is performed before transplantation, which allows to remove tumor cells from the body as much as possible and overcome their drug resistance to chemotherapy drugs.
The success of transplantation depends on the activity of the disease itself (the state of remission) and the physical condition of the patient (age, concomitant diseases, functional state of the main organs and systems).
Indications for autologous transplantation are:
- Hodgkin’s lymphoma (lymphogranulomatosis), non-Hodgkin’s lymphomas – transplantation is performed when standard therapy is ineffective or the disease relapses (returns).
- Multiple myeloma is performed as one of the main stages of treatment for most of the newly diagnosed patients.
- Acute leukemia is considered as a contraindication for autologous transplantation with the exception of acute promyelocytic leukemia or within the framework of research protocols.
- Malignant tumors of the non-hematopoietic system — testicular cancer, some types of sarcomas (in particular, Ewing’s sarcoma), glioblastoma in children.
- Autoimmune diseases — multiple sclerosis, other autoimmune diseases of the nervous system, systemic scleroderma, thymoma.
Allogeneic transplantation is a type of transplantation in which donor hematopoietic cells (bone marrow, hematopoietic stem cells of peripheral blood, cord blood hematopoietic cells) are transplanted, fully or partially compatible on a genetic basis. The probability of genetic coincidence of the similarity of the hematopoietic tissue of relatives is no more than 25%.
Therefore, partially compatible hematopoietic cells of non-relative donors have been increasingly used recently. The search for an unrelated donor is carried out in the bone marrow donor registry, in which a donor compatible with the patient is selected. Compatibility is determined after laboratory tests that determine the genetic profile of donor and patient tissues, this study is called HLA typing – tissue compatibility antigens (human leucocyte antigens). 5-10 ml of blood from the donor and recipient is enough for the study.
Indications for this type of transplantation are:
- Acute leukemia and some forms of chronic leukemia – in the first and subsequent remissions.
- Severe aplastic anemia — in the absence of the effect of immunosuppressive therapy or relapse after its implementation.
- Congenital immunodeficiency conditions in children.
- Relapses of lymphoma after autologous transplantation.
Tags: bone marrow transplantation, human health, surgery