Bone Marrow Transplantation
The treatment of choice for aplastic anemia and severe combined immunodeficiency diseases, bone marrow transplantation involves the infusion of fresh or stored bone marrow into a recipient. The procedure may also be used to treat acute leukemia, chronic leukemia, lymphoma, multiple myeloma, and certain solid tumors. Recently, bone marrow transplantation has been useful in the treatment of sickle cell anemia.
The bone marrow used in the transplantation may be obtained by autologous, syngeneic, or allogeneic means. In an autologous donation, the bone marrow is harvested from the patient before he receives chemotherapy or radiation therapy, or while he’s in remission, and then frozen for later use.
In a syngeneic donation, bone marrow is taken from the patient’s identical twin. Obviously, syngeneic donations are rare. But, when possible, they are the ideal type. That is because an identical twin has healthy bone marrow that is histologically identical to the patient’s own tissue.
The most common type of transplant involves an allogeneic donation. For this procedure, bone marrow is obtained from a histocompatible individual. This is usually a sibling, although it’s possible for an unrelated donor to meet the requirements. Because the donor’s and patient’s tissue don’t match perfectly, the patient must receive medications to suppress his immune system. Even then, the procedure isn’t always successful.
A new method, peripheral stem cell transplantation, involves the collection of peripheral stem cells, usually after the patient has been treated with chemotherapy or growth factors to increase the number of circulating stem cells. The cells are stored and later reinfused into the patient after high-dose chemotherapy and, possibly, radiotherapy.
Procedure
If the patient will be receiving his own bone marrow, the donation will have been
made 2 weeks earlier and frozen. For a syngeneic or allogeneic transplant, physicians will obtain the donor bone marrow in the operating room the same day as the transplant. (See Teaching about bone marrow donation.)
made 2 weeks earlier and frozen. For a syngeneic or allogeneic transplant, physicians will obtain the donor bone marrow in the operating room the same day as the transplant. (See Teaching about bone marrow donation.)
The transplantation procedure itself will occur at the patient’s bedside. Just before the procedure, administer an antihistamine or analgesic as ordered to minimize adverse reactions. In the case of an allogeneic or syngeneic donation, someone will bring the bone marrow to the patient’s room as soon as it’s obtained. For an autologous donation, the marrow will be allowed to thaw. Then, as soon as the marrow has been made available or has thawed, the physician will infuse it into the patient through a central venous catheter.
The rate of infusion varies, depending on the volume of marrow being infused. Once infused, the marrow cells will migrate to the patient’s marrow cavity, where they’ll begin to proliferate. This process, called engraftment, takes from 10 days to 4 weeks.
