I. What is the preparation needed for blood stem cell transplantation? First of all, there is the issue of donor selection. With the advent of the one-child era, it is becoming more and more difficult to choose a donor by matching between siblings. In addition to parents and children, we now mainly rely on bone marrow banking to find a donor with a matching human leukocyte antigen (HLA) system and collect a certain number of HSCs from the donor. The second is pre-treatment before transplantation. This is to enable the recipient to reduce the load of his own tumor cells and to make “space” for receiving foreign HSCs, and also to remove lymphocytes in the peripheral blood that can react on their own and reject the donor bone marrow cells after transplantation. What are the types of hematopoietic stem cell transplantation? Hematopoietic stem cells can come from bone marrow, peripheral blood and umbilical cord blood, so accordingly, hematopoietic stem cell transplantation can be divided into bone marrow transplantation, peripheral blood stem cell transplantation and umbilical cord blood stem cell transplantation. Similarly, according to the source of HSCT, it can be divided into patient or donor, and according to whether the donor is genetically identical to the patient, it can be divided into autologous transplantation, allogeneic transplantation and allogeneic transplantation. Allogeneic transplantation refers to transplantation between a patient and a donor with identical genes, as in the case of an egg twin brother or sister. For acute leukemia without a suitable donor, after complete remission of treatment, the patient’s own hematopoietic stem cells are taken for transplantation, which is called autologous transplantation. What is autologous hematopoietic stem cell transplantation? As the name suggests, autologous hematopoietic stem cell transplantation means that one’s own hematopoietic stem cells are extracted from the body and then transfused back to the autologous body, so that “one out and one in” can cure one’s own disease? Some people may have this question. In fact, it is not a simple “one out, one in”, but the “out” refers to the autologous hematopoietic stem cells collected during a specific period when the patient is in remission with very few malignant cells in the bone marrow or peripheral blood, and after the collection, they have to be purified and genetically amplified in vitro to make their own After collection, the autologous HSCs have to be purified and genetically amplified in vitro to turn their “unclean” autologous HSCs into “clean” ones, and through amplification, the amount of such “clean” HSCs is increased and then transfused back to the autologous body to promote hematopoietic recovery and hematopoietic reconstruction. What are the complications associated with hematopoietic stem cell transplantation? Early complications after transplantation include: 1. Infections, including bacterial, fungal and viral infections and Pneumocystis carinii pneumonia, of which interstitial pneumonia (IP) caused by cytomegalovirus (CMV) is the most serious. 2. 2, hepatic veno-occlusive disease (VOD), the clinical symptoms of which are unexplained weight gain, jaundice, right upper abdominal pain, hepatomegaly and ascites. 3. graft-versus-host disease (GVHD), which is a rejection reaction to transplantation. Late complications include: 1. cataracts, mainly related to total body irradiation, which can also be promoted by the use of drugs such as glucocorticoids and cyclosporine. White matter encephalopathy, mainly seen in patients with combined central nervous system leukemia (CNSL) who receive repeated intrathecal chemotherapy and systemic high-dose radiotherapy and chemotherapy. 3.Endocrine disorders, manifested as reduced thyroid and gonadal functions. 4.Secondary tumor, a few patients develop lymphoma or other solid tumors after several years. V. What is the rejection reaction of hematopoietic stem cell transplantation? The immune function of human body has the function of “know oneself and exclude others”, everything in one’s own body can coexist peacefully, but everything that is not in one’s own body should be rejected by all means. In the transplantation of hematopoietic stem cells, if the mating is fully compatible, the body can treat this “other” as “self” and not reject it, but even if the HLA is fully compatible between the donor and the recipient, the six loci currently tested are compatible and no other minor loci are detected to be incompatible. Therefore, transplant rejection exists to a greater or lesser extent. Then we should prevent and deal with this rejection phenomenon, prevention is to look for a fully compatible donor as much as possible, treatment is to use some drugs to reduce the body’s “self-rejection” effect, however, once this effect is reduced also opens a channel for the invasion and infection of pathogenic bacteria, because under normal circumstances through However, once this effect is reduced, it also opens the way for pathogenic bacteria to invade and infect the body, because under normal circumstances, the body can repel pathogenic bacteria through the effect of “self-exclusion”. Therefore, the two main problems after transplantation are rejection and anti-infection. Sixth, why will relapse after hematopoietic stem cell transplantation? Some leukemia patients may relapse after bone marrow transplantation for various reasons, such as: 1. incomplete pretreatment, there are tiny residual lesions in the body, i.e. there are a small amount of residual leukemia cells, which is the reason why radiotherapy is still needed after transplantation. If the patient is insensitive or tolerant to radiotherapy and the residual leukemia cells replicate in large numbers, it can also lead to relapse. 2. The post-transplantation anti-rejection regimen is too powerful, and although it avoids the appearance of graft-versus-host disease (GVHD), it also prevents the leukocytes in one’s own body from playing an effective anti-leukemia role. Currently, the purpose of clearing residual lesions in the body is mostly achieved through the induction of graft-versus-leukemia (GVL) by transfusion of donor leukocytes. VII. Will the patient’s blood type change after bone marrow transplantation? After receiving a bone marrow transplant, the implanted donor bone marrow will participate in the blood production of the patient’s body, so the blood type will become the same as that of the donor. If the donor’s blood type is different from the patient’s original blood type, the patient’s blood type will change to the donor’s blood type after transplantation. For example, if the patient has type A blood and the donor has type B blood, the patient’s blood type will change to type B after transplantation. How does bone marrow function as a hematopoietic agent? There is a kind of pluripotent hematopoietic stem cells in human bone marrow, which can not only differentiate various more mature cells, such as red blood cells, white blood cells and platelets in blood cells, but also replicate the stem cells that are identical to their own. Thus, the amount of such hematopoietic stem cells in the body remains constant to a certain extent and can perform the function of generating subsequent mature cells, i.e. performing its continuous hematopoietic function. Is bone marrow donation harmful to the human body? Cells in the human body are constantly undergoing metabolism, and so are the hematopoietic stem cells in the bone marrow. When some hematopoietic stem cells are damaged, healthy stem cells are quickly born to compensate for it. When bone marrow is donated, only a small portion of bone marrow is withdrawn from the body, and only a portion of the pluripotent stem cells are lost. The remaining pluripotent stem cells will quickly replicate, and the hematopoietic function will be completely restored to normal within a short period of time. Therefore, donating bone marrow will not pose any harm to human body. X. What is the specific process of bone marrow donation? With the development of science and technology, “bone marrow transplantation” has been gradually replaced by “hematopoietic stem cell transplantation”, that is, first of all, by giving a “mobilizer” to the successful donor, so that the donor The blood stem cells in the bone marrow are released into the peripheral blood in large quantities. Then, through the blood cell separation machine from the donor’s peripheral blood separation to obtain a large number of blood stem cells, that is, now donor bone marrow is no longer extracted from the bone marrow, but only “blood donation”. XI. How to apply for bone marrow donation? Healthy citizens between the ages of 18 and 45 can voluntarily apply for bone marrow donation at their local Red Cross Society and after registration, 5 ml of blood will be taken for “safety” and “matching” tests. The safety test is a test to see if the donor has certain diseases, while the matching test is a test for human leukocyte antigens in the donor’s bone marrow. When your blood is tested and confirmed as “safe”, your “matching” data will be recorded in the “Chinese Bone Marrow Bank”, so you are a member of the bone marrow donor. Can blood transfusions and transplants spread diseases? Although many infectious factors (such as viruses) have been tested on donor blood and grafts before transfusion and transplantation, there are still some factors that cannot be detected under current medical conditions, or the donor’s disease is still in the window period, and the infectious factors cannot be detected and the donor’s blood is mistakenly considered to be “qualified”. “Therefore, it cannot be ruled out that transfusions and transplants can transmit some diseases. The most common are post-transfusion hepatitis, AIDS, syphilis, malaria, transfusion-associated acute lung injury, etc.