The idol drama “Blood Doubt”, which must be watched by thousands of families in the 1980s, made people recognize stars such as Momoe Yamaguchi and Tomo Miura, and also recognize blood cancer, which is actually a malignant tumor of the blood system – leukemia, and after several generations of After several generations of efforts, leukemia is no longer an incurable disease, and now hematopoietic stem cell transplantation has become an important and even the only means to cure leukemia. So what is hematopoietic stem cell transplantation? The following is a brief introduction to some basic knowledge about HSCT Question 1: What is HSCT? Hematopoietic stem cell transplantation is the replacement of a patient’s diseased hematopoietic and immune functions with healthy or relatively healthy hematopoietic stem cells. Question 2: What types of hematopoietic stem cell transplantation can be classified? HSCT can be divided into three categories: The first category is allogeneic transplantation, which means that the genes of the patient receiving the transplant are identical to those of the donor providing the stem cells, for example, transplantation between identical twins. The second category is allogeneic HSCT, which means that the genes of the transplant recipient and the donor are not identical, but the human leukocyte differentiation antigen (HLA) match is compatible, which is often referred to as having a suitable donor; of course, HLA compatible HSCs can be derived from siblings, unrelated donors, and umbilical cord blood. In recent years, the development and maturation of HLA-compatible allogeneic HSCT technology has made it possible for almost all patients who need transplantation to have the opportunity to do so. The third type of transplantation is autologous HSCT, which refers to the process of removing relatively healthy HSCs from a patient and returning them to the patient after high-dose chemotherapy and/or radiotherapy to re-establish normal hematopoietic and immune functions, such as autologous HSCT for lymphoma. As can be seen, although the above classifies HSCT into three categories, these three categories can be grouped into two categories, namely allogeneic HSCT and autologous HSCT. Question 3: What is the simple process of hematopoietic stem cell transplantation? Figure 1: Simple process of autologous HSCT Question 4: What are the diseases that can be treated by HSCT? HSCT can be used to treat a variety of diseases: acute leukemia, chronic leukemia, lymphoma, myelodysplastic syndrome, aplastic anemia, multiple myeloma, and macroglobulinemia in the hematologic system; genetic diseases such as Fanconi anemia and thalassemia; autoimmune diseases such as systemic lupus erythematosus, myasthenia gravis, rheumatoid arthritis, and multiple sclerosis The following are examples of autoimmune diseases: systemic lupus erythematosus, myasthenia gravis, rheumatoid arthritis, and multiple sclerosis, idiopathic thrombocytopenic purpura. Solid tumors: such as lung cancer, kidney cancer, etc. In addition, hematopoietic stem cell transplantation for some diseases is in the research stage, such as Alzheimer’s disease. Of course, what kind of patients, at what stage of the disease and what kind of transplant should be used? These are questions that must be answered by a specialist in the field of hematopoietic stem cell transplantation in a regular hospital. Question 5: What is the probability of finding a suitable donor? The probability of finding an HLA compatible donor among siblings is 25%-30%; the probability of finding an HLA compatible donor through a bone marrow bank is 1 in 5-100,000; if a haploidentical donor is found, then almost every patient who needs a transplant can find a haploidentical donor. Question 6: What is the efficacy of HSCT for leukemia? The 5-year survival rate of allogeneic HSCT for acute lymphoblastic leukemia and acute myeloid leukemia can reach about 60%, although the survival rate depends on various factors such as the size of the transplant center, the experience of the doctor, and the condition of the patient before transplantation. Question 7: What are the common complications of allogeneic stem cell transplantation? The common complications of allogeneic HSCT include infection (including bacteria, virus, fungus, etc.), graft-versus-host disease (including acute graft-versus-host disease and chronic graft-versus-host disease), disease relapse, etc. Question 8: What is the current number of registered donors in the Chinese Bone Marrow Bank? Currently, the number of registered donors in the Chinese Bone Marrow Bank is about 1 million. Patients who need to undergo HSCT from unrelated donors need to inquire with the bone marrow bank by hospitals with recognized qualifications. Question 9: How many cord blood banks are there in China? There are currently four to ten cord blood banks in China by 2010, including Beijing Cord Blood Bank, Tianjin Cord Blood Bank, Jinan Cord Blood Bank and Guangzhou Cord Blood Bank. Due to the small number of nucleated cells in cord blood, they are currently used mainly for transplantation in pediatric patients. The development of double cord blood transplantation brings hope for adults to perform cord blood transplantation. Question 10: What are the advantages of allogeneic peripheral blood HSCT? The advantages of allogeneic peripheral blood HSCT are as follows: 1. faster reconstruction or recovery of hematopoietic and immune functions; 2. safer collection of stem cells; 3. less chance of infiltration or contamination by tumor cells; 4. potential anti-leukemia effect of the graft. Question 11: What are the advantages and disadvantages of umbilical cord blood transplantation? The incidence of GVHD in cord blood transplantation is significantly lower than bone marrow transplantation; 2. The HLA mapping requirement for unrelated cord blood transplantation is relatively low; 1-3 loci can be transplanted, so there are more potential donors than bone marrow; 3. The disadvantages of cord blood transplantation are: 1. limited number of cells in cord blood and therefore limited application for adults; 2. delayed implantation and longer immune recovery time. The above is a part of basic knowledge about transplantation, because hematopoietic stem cell transplantation is a systematic and complex project, not something that can be explained in a short space, I hope the above knowledge will be helpful to patients and families.