BONE MARROW TRANSPLANTATION
- Bone marrow transplantation (BMT) and peripheral blood stem cell transplantation (PBSCT) are procedures that replace stem cells that have been destroyed by high doses of chemotherapy and/or radiation therapy.
- BMT and PBSCT are most commonly used in the treatment of leukemia and lymphoma, but are also used to treat other cancers, such as neuroblastoma and multiple myeloma.
- The goal of treatment is to rid the client of all leukemic or other malignant cells through treatment with high doses of chemotherapy and whole-body irradiation.
- Because these treatments are damaging to bone marrow cells, without the replacement of blood-forming stem cell function through transplantation, the client would die of infection or hemorrhage.
Types of donor stem cells
- Allogeneic: Stem cell donor is usually a sibling, parent with a similar tissue type, or a person who is not related to the client (unrelated donor).
- Syngeneic: Stem cell is from an identical twin.
- Autologous donation is themost common type.
- The client receives his or her own stem cells.
- Stem cells are harvested during disease remission and are stored frozen to be reinfused later.
- The stem cells used in PBSCT come from the bloodstream in a 4- to 6-hour process called apheresis or leukapheresis (the blood is removed through a central venous catheter and an apheresis machine removes the stem cells and returns the remainder of the blood to the donor).
- In BMT, marrow is harvested through multiple aspirations from the iliac crest to retrieve sufficient bone marrow for the transplant.
- Marrow is filtered for residual cancer cells.
- Allogeneic marrow is transfused immediately; autologous marrow is frozen for later use (cryopreservation).
- Harvesting is done before the initiation of the conditioning regimen.
- Conditioning refers to an immunosuppression therapy regimen used to eradicate all malignant cells, provide a state of immunosuppression, and create space in the bone marrow for the engraftment of the new marrow.
- Stem cells are administered through the client’s central line in a manner similar to that for a blood transfusion.
- Stem cells may be administered by IV infusion or by IV push directly into the central line.
- The transfused stem cells move to the marrow- forming sites of the recipient’s bones.
- Engraftment occurs when the white blood cell, erythrocyte, and platelet counts begin to rise.
- When successful, the engraftment process takes 2 to 5 weeks.
- Post-transplantation period: Infection, bleeding, or neutropenia and thrombocytopenia are major concerns until engraftment occurs. During the post-transplantation period, the client remains without any natural immunity until the donor stem cells begin to proliferate and engraftment occurs.
Failure to engraft: If the transplanted stem cells fail to engraft, the client will die unless another transplantation is attempted and is successful.
- Although the recipient cannot recognize the donated stem cells as foreign or non-self because of the total immunosuppression, the immune-competent cells of the donor recognize the recipient’s cells as foreign and mount an immune offense against them.
- Graft-versus-host disease is managed with immunosuppressive agents cautiously to avoid suppressing the new immune system to the extent that the client becomes more susceptible to infection, or the transplanted cells stop engrafting.
- Veno-occlusive disease
- The disease involves occlusion of the hepatic venules by thrombosis or phlebitis.
- Signs include right upper quadrant abdominal pain, jaundice, ascites, weight gain, and hepatomegaly.
- Early detection is critical because there is no known way to open the hepatic vessels.
- The client will be treated with fluids and supportive therapy.