Bone Marrow Transplant

When the immune response is severely depressed-as the result of inherited defects, cancer therapy, or AIDS-one possible remedy is transfer of healthy bone marrow.

Bone marrow is the spongy center of our bones where blood is produced. It is also the home of out immune system. Bone marrow contains the parent cells, called stem cells, that later mature into white blood cells (infection fighting cells), red blood cells (oxygen carrying cells), and platelets (which aid in blood clotting). The numbers of our blood cells will be closely monitored throughout the transplant process. As our transplant marrow begins to produce blood cells, our blood counts will begin to rise and body will begin to regain immunity, strength, and energy.

When the immune response is severely depressed-as the result of inherited defects, cancer therapy, or AIDS-one possible remedy is transfer of healthy bone marrow.

Bone marrow transplants are also used to treat patients with cancers of the blood, the blood forming organs, and the lymphoid system-the leukemias and lymphoma.

Once in the circulation, transplanted bone marrow cells travel to the bones where the immune cells grow into functioning B and T cells. Like other transplanted tissue, however, bone marrow from a donor must carry self markers that closely match those of the person intended to receive it.

This match is essential not only to prevent the transplant from being rejected, but also to fend off a life threatening situation known as graft-versus-host disease. In graft-versus host disease, mature T cells from the donor attack and destroy the tissue of the recipient.

To prevent graft-versus-host disease, scientists have developed techniques to “cleanse” the donor marrow of potentially dangerous mature T cells. These include chemicals and, more recently, a monoclonal antibody (OKT3) that specifically recognizes and eliminates mature T cells.

For cancer patients who face immunosuppressive therapy but who have no readily matched donor, doctors have used “autologous” transplants: the person’s bone marrow is removed, frozen, and stored until therapy is complete; then the cells are thawed and reinfused.