As for indications, it is generally believed that: severe bone marrow failure (severe aplastic anemia, except the elderly), granulocyte lymphocytes in more than 75%; It is best to do it within 3 months after diagnosis; Under 20 years old; It is best not to transfuse blood before transplantation to reduce rejection after transplantation. No obvious infection; The same is true of HLA tissue matching.
Preparation before transplantation: Most of the donors are brothers and sisters of patients, but the probability of any tissue matching between brothers and sisters is only 25%. Even if HLA matching and MLC (mixed lymphocyte culture) are suitable, there will be some unknown antigens that will cause immune rejection and may lead to transplantation failure. Therefore, the immune system of patients with aplastic anemia must be "completely" suppressed before transplantation. Generally, large doses of cyclophosphamide are given before transplantation.
Bone marrow transplantation: bone marrow tissue (about 800ml mixed with blood) is extracted from multiple bone marrow of donors, which contains at least 654.38 billion bone marrow nucleated cells. After filtration, intravenous injection was performed. 2 ~ 3 weeks after transplantation, if donor blood cells appear in the patient's blood circulation, it means that bone marrow transplantation has been initially successful. It should be noted that bone marrow transplantation has not yet taken root.
Before, patients were in danger of serious infection and bleeding, so strict aseptic isolation and sterilization measures must be taken for gastrointestinal tract, mouth and skin to prevent bacterial and mold infection.
If there are signs of infection, it is necessary to transfuse concentrated white blood cells many times and give a lot of antibiotics against bacteria and mold. At the same time, in order to prevent bleeding, concentrated platelets need to be infused.
Reasons for the failure of bone marrow transplantation: before transplantation, patients were sensitized to bone marrow donors because of blood supply from their families; Serious infection or bleeding was not controlled before bone marrow transplantation took root; Graft-versus-host disease (GVHD) refers to acute or chronic damage to patients' skin, liver, gastrointestinal tract and other tissues. After the transplanted tissue survives and reproduces, the cells with immune function react with the antigens in the patient's original tissue. About 70% of transplant patients will happen, and half of them will die. Therefore, it is effective to give high-dose methotrexate or cyclosporine to inhibit GVHD reaction after transplantation, and to give whole serum in acute stage.