This is a procedure done to replace the diseased bone marrow with healthy bone marrow/stem cells. Patients suffering from diseases such as thalassemia, leukemia, lymphoma, aplastic anemia, multiple myeloma, etc. may need to undergo this transplant.
Bone marrow is the soft, spongy center of the bone where blood is produced. It contains stem cells that are the precursors of white blood cells, red blood cells, and platelets which perform vital functions like oxygen transport, defense against infection and disease, and clotting.
It can be an allogeneic transplant, where donor bone marrow, umbilical cord stem cells or peripheral stem cells are transplanted from a genetically matched donor, who can be related or unrelated to the patient. HLA matching is essential for a successful transplant.
An autologous transplant involves receiving one’s own bone marrow or peripheral stem cells.
First step consists of harvesting the donor marrow/stem cells.Under general anaesthesia, bone marrow is drawn from the iliac crest ( part of the hip bone). Peripheral blood stem cells are obtained from circulating blood rather than from bone marrow which can be used in either autologous or allogeneic transplants. Marrow is stored at -112–-320°F (-80–-196°C) until it is needed.
The recipient is prepared by giving very high-doses of chemotherapy and/or radiation therapy, so as to eliminate the diseased marrow and make room for the new marrow.
The infusion of the new marrow, cord blood, or peripheral stem cells from the donor is administered to the recipient via a catheter inserted into a large vein in the chest. From the bloodstream, it migrates to the cavities within the bones where bone marrow is normally stored, thus replacing the bone marrow destroyed by the chemotherapy and/or radiation therapy.
The complete procedure is long and complicated and is to be done with utmost care. Patient needs to stay in hospital for 4-6 weeks. This includes the initial testing period, followed by chemotherapy/radiotherapy and finally the infusion with donor marrow.
The marrow recipient is kept in isolation for initial critical period of 2-4 weeks, to minimize potential infections. The recipient also receives intravenous antibiotic, antiviral, and antifungal medications, as well as blood and platelet transfusions to help fight off infection and prevent excessive bleeding. Daily monitoring of patient’s status is done.
Even after discharge from hospital, care is to be taken to avoid any potential infections. Normal activities can be resumed about six to eight months after the transplant.
The transplant may be rejected by the recipient's immune system, or the donor bone marrow may launch an immune-mediated attack against the recipient's tissues. This complication is called graft-versus-host disease, and if severe, it can be a life-threatening.
Besides, there is risk of pneumonia or other infectious disease, excessive bleeding, or liver disorder. Late complications include skin changes such as dryness, altered pigmentation, and thickening; weight loss, cataracts, abnormal lung function, hormonal abnormalities, secondary cancers, infertility, etc.
Under specialized care at some of the best centres in India, chances of a successful transplant are very high. The doctors are highly skilled and experienced in this field.