A procedure in which a person receives stem cells, the cells from which all blood cells develop, from a compatible, though not genetically identical, donor.
The replacement of an individual’s defective bone marrow with the bone marrow or stem cells of a healthy donor. Stem cells (cells from which the different types of blood cells develop) are present in normal bone marrow and blood. In an allogeneic transplant, the donor is usually a sibling, other relative, or a nonrelative whose marrow is closely matched to that of the recipient’s.