Bone marrow

Bone marrow, the center of large bones, is the place where new blood cells are produced. Bone marrow contains stem cells which produce three types of blood cells: leukocytes, red blood cells, and platelets.

Bone marrow can be transplanted. It is extracted from the largest bones, typically the sternum[?] or the hip, of a HLA-compatible donor by a large needle that reaches the center of the bone and is transfused like blood into the patient.

A compatible donor is found by doing blood tests on potential donors. Perfect matches, the donor matches on all six HLA types[?] result in the most successful transplants. Less perfect matches, four or five matches, can also result in successful transplants but the risk of rejection is greater.