What is a bone marrow
Bone marrow is found in long bones (such as the humerus, femur) and flat bone marrow cavity (such as the iliac crest, ribs, sternum, spine, etc.) in the cancellous bone between the mesh of a sponge-like tissue, bone marrow produces blood cells slightly red, as red bone marrow. Some of the bone marrow cavity of adult bone marrow contains a lot of fat cells, yellow, and can not produce blood cells, known as the yellow bone marrow. At birth, the body cavity filled with red bone marrow, with age, increased bone marrow fat cells, a considerable part of the red bone marrow is replaced by yellow and finally almost alone in the flat bone spongy bone with red bone marrow. Such changes may not need all the marrow cavity of adult blood, some of the bone marrow cavity blood to replenish blood cells is adequate. When the body during severe ischemia, part yellow marrow can be transformed into red bone marrow and restore the ability of blood.
What is the role of bone marrow
The body's blood components and in a constant metabolism, the old cells are removed, generating new cells, bone marrow generate a variety of important functions is to produce cells, stem cells, these stem cells through differentiation and then generate a variety of blood cells such as red blood cells, white blood cells , platelets, lymphocytes, etc., simply is the role of bone marrow hematopoietic function. Therefore, the bone marrow of life for the maintenance of the body and immunity is very important.
Bone marrow transplantation
(English: bone marrow transplantation, BMT)
An organ transplant, the patients with normal bone marrow in vivo by the intravenous infusion to replace the treatment of bone marrow lesions. For the treatment of hematopoietic function abnormalities, immune dysfunction, hematological malignancies and other malignancies. With this therapy can improve efficacy, improve outcomes, have long survival and even cure.
Two types of transplant
One for allogeneic bone marrow transplantation (clinical applications since the 1970s, has achieved great success.) It is with the patient the need for human leukocyte antigen (HLA) matching brothers, sisters and a handful of unrelated marrow for allogeneic bone marrow who have entered, or family members such as parents and their children's bone marrow transplantation; and with patients HLA does not quite match unrelated donor bone marrow. Although non-compatriots, brothers and sisters HLA match, but susceptible to varying severity of graft versus host disease (GVHD), especially in the latter case is more serious. Another bone marrow transplantation for the same gene, that is a very small number of monozygotic twins among twin brother or sister of bone marrow transplantation.
Another type of autologous bone marrow transplantation (ABMT). To carry out such a late bone marrow transplantation, 80 clinical application. With their own bone marrow, for marrow without those, this method is simple, easy to spread, can be used for only one child, and no incidence of GVHD. For leukemia, lymphoma and various solid tumor treatment.
Human leukocyte antigen (HLA) loci exist on chromosome 6 in both the short arm, each with and by the closely linked loci of complex composition. Each locus by several or dozens of alleles in a composition. The cell membrane, there are currently 200 species found around the antigen. Currently available in the laboratory to the HLA antigen detected only HLA-A-BC, -D/DR these categories. Laboratory measured these types of antigen match between the two does not mean they are not all antigens inconsistencies. In the brothers, and sisters all received from the parents of each gene on a chromosome one, so is the haploid genetic. Brothers and sisters with exactly the same way between the rate of gene accounted for only 25% of the total between parents and offspring chromosomes have a single type of HLA-A, B and other sites with different, so in addition monozygotic twin brother or sister, the Family members and unrelated donor HLA match between the probability is minimal.
HLA started as a human major histocompatibility complex (MHC) was found, the expression of the gene encoding the antigen, involved in controlling cell subsets in immune recognition and interaction, it does not match the HLA on graft and recipient organizations mutually exclusive influence. Clinically, on the one hand can not produce graft engraftment, on the other hand can produce varying severity of acute and chronic graft-versus-host disease, manifested as skin, liver and gastrointestinal diseases, severe cases can lead to death. Therefore, HLA matching on the organization's choice for the marrow and bone marrow transplant success, is one important part.
About 60% of adult acute leukemia patients after allogeneic bone marrow transplantation or with up to 3 years of long survival, some have reached 5 to 6 years. Chronic myeloid leukemia in chronic phase, about 80% of patients can survive for 3 years, some have survived more than 5 to 6 years can be described as radical. Was compared with conventional combined chemotherapy only, do not do bone marrow transplantation in acute leukemia, only 10 to 15% of people survived to 3 years, the average survival is only about a year. Chronic myeloid leukemia survival period was 3 to 4 years, although the slow course of the disease, but no cure with chemotherapy is currently possible. Therefore, the efficacy of bone marrow transplantation achieved better than conventional chemotherapy. Of lymphoma and other solid tumors with autologous bone marrow transplantation can achieve radical purposes.
Principle
Select the appropriate patients, the right time. With leukemia as an example: adult acute leukemia in first complete remission (At this point the body is still ≤ leukemia cells), CML in chronic phase, with large doses of chemotherapy and radiotherapy pretreatment, the patient's body to further kill leukemia cells out. At the same time the patients immune system and bone marrow function is extremely inhibited, so that the latter is difficult to self-recovery, then the donor (for acute and chronic myeloid leukemia) or removed prior autologous bone marrow (for complete remission of acute leukemia) intravenous infusion to patients, to save, and pay attention to bleeding may occur during infection and other complications, to take effective measures, waiting for the normal hematopoietic function reconstruction in a few weeks to achieve cure.
Outlook
Allogeneic and autologous bone marrow transplantation has advantages and disadvantages, ABMT the biggest drawback for the high recurrence rate, therefore, must be removed with acute leukemia and bone marrow of patients with advanced solid tumors in the residual leukemia or tumor cells. Means the removal of current research include: use of monoclonal antibodies plus complement, monoclonal antibodies plus plant lectin, monoclonal antibodies and magnetic micro-particle method, and the long-term bone marrow culture method, using a special culture system selectively only for normal hematopoiesis cell growth, above all phenomena can be achieved to kill residual leukemia or tumor cells, or interfere with their growth, in order to achieve the purpose of purification.
Allo-BMT, in order to eliminate or reduce the occurrence of GVHD, the first recipient and donor HLA matching to be accurate and reliable in addition to conventional HLA-A,-B,-C,-DR matching, the two sides should make further mixed lymphocyte culture in order to understand the HLA-D and the other not yet possible to detect a single other human leukocyte antigen degree of consistency between, and further estimate the possible transplantation of bone marrow engraftment can not be excluded or the occurrence of graft level-versus-host disease. Cyclosporine A is a strong preventive T cells to antigen stimulation drugs. Monoclonal antibodies also can be used for the removal of T lymphocytes in the spinal cord to relieve or avoid it caused by the occurrence of GVHD and reduce mortality.
Medical significance
Bone marrow transplants are used to treat those diseases
Bone marrow transplantation is a fairly advanced treatment, mainly for the treatment of acute and chronic leukemia, severe aplastic anemia type, Mediterranean anemia, lymphoma, multiple myeloma and is now trying to further the treatment of metastatic breast and ovarian cancer .
Source of bone marrow
Bone marrow transplantation of autologous bone marrow transplantation and allogeneic bone marrow transplantation of the points, by definition, autologous bone marrow transplantation of bone marrow from patients themselves, allogeneic bone marrow transplantation with bone marrow from the donor.
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