Bone Marrow Transplants

Bone is living tissue whose cells undergo an unending cycle of being destroyed and replaced. As with any living tissue, bone requires nourishment, which it receives through tiny blood vessels that penetrate the periosteum, the tough, fibrous membrane that envelops the bone, and weaves through the bone to the marrow. Plasma, rather than whole blood, nourishes bone cells. The red marrow of certain bones in the body manufactures red blood cells and platelets. Red cells are needed to carry oxygen to cells, while platelets enable blood to clot.

Several blood diseases are caused by malignant growth in the bone marrow or by malfunctioning bone marrow. The best known and most devastating of these is leukemia, which destroys normal marrow operation. Sickle cell anemia is a hereditary defect in the formation of red blood cells which kills about 80,000 children world-wide each year. Victims of such diseases are now being helped by transplanted bone marrow.

Georges Mathe, a French physician, was the first to experiment with bone marrow transplantation in treating leukemia in the early 1960's. The procedure involves administration of heavy doses of anti-cancer drugs and radiation to kill leukemia cells.

Several weeks following this treatment, healthy bone marrow is infused into the patient. Bone marrow is usually withdrawn several times from the hip bone of the donor through a needle. These samples are pooled and the marrow particles are isolated by straining. Strained bone marrow cells are then given to the recipient through a vein in the arm as a blood transfusion. The bone marrow cells find their way to the bone cavities and begin to repopulate these areas with normal cells.

The problem of tissue matching is critical for bone marrow transplants, more so than for transplantation of other organs. Ideally, there should be a perfect match of six markers (antigens) on the surface of the donor and recipient blood cells.