There are many types of blood disorders, only a few of which are curable and have a good prognosis, most of which are refractory and pose a great threat to patients’ lives. In the treatment of blood disorders we often hear about “bone marrow transplantation”, indeed, bone marrow transplantation is currently the only way to cure these refractory blood disorders. Here’s what we know about bone marrow transplantation: What is a bone marrow transplant? Given that leukemia cells remain in the body after a leukemia patient is in complete remission, these cells are a source of relapse. Hematopoietic stem cell transplantation is a method of re-establishing hematopoietic and immune functions by transplanting hematopoietic stem cells from bone marrow or peripheral blood after pretreatment with high-dose chemotherapy and/or radiotherapy for the patient. Bone marrow transplantation is the most commonly used method of HSCT because of the abundance of HSCs in bone marrow; peripheral blood and cord blood also contain a certain amount of HSCs. According to the source of HSCs and the way of collection, HSC transplantation is clinically classified into the following five types: 1. genetic bone marrow transplantation: transplantation between homozygotes, which is the most commonly used transplantation method; 2. homozygous bone marrow transplantation: transplantation between twin siblings, which has a low chance of occurrence; 3. own bone marrow transplantation: bone marrow collected from the patient’s own remission period, so it is more widely carried out; 4. 4. peripheral blood stem cell transplantation: includes self or allogeneic peripheral blood stem cell transplantation; 5. umbilical cord blood transplantation: is currently used mainly for children with small body weight because of the small amount of blood stem cells collected. Allogeneic bone marrow transplantation is the most common, so what is it all about? Allogeneic bone marrow transplantation is a method of transplanting bone marrow from another person (non-identical twin) into the recipient so that the bone marrow rich in hematopoietic stem cells can grow and multiply in the recipient. An allogeneic bone marrow transplant is one in which the recipient is genetically identical to the donor, i.e., an identical twin transplant. The advantage of allogeneic bone marrow transplantation is that the transplanted bone marrow is extremely unlikely to be rejected and the recipient is less susceptible to graft-versus-host disease. As a result, the incidence of comorbidities during transplantation is low and safety is high. In contrast, allogeneic bone marrow transplantation has the disadvantages of graft rejection and graft-versus-host disease, but it has the effect of graft-versus-leukemia secondary immunotherapy, which can significantly reduce the recurrence rate of leukemia after transplantation, thus creating a chance for long-term disease-free survival and cure for more patients. What are the conditions for patients to receive allogeneic bone marrow transplantation? Patients should have indications, leukemia is an indication for transplantation; 2. Patients should not be older than 45 years old (or 50 years old), older patients have a higher mortality rate associated with transplantation; 3. Patients should not have other fatal and serious diseases, such as severe heart disease, severely impaired liver and kidney function and mental illness; 4. Donors with suitable tissue matches are available; 5. Sufficient cost sources, generally more than 150,000 RMB is needed.