Nonmyeloablative allogeneic stem cell transplantation using alternative donors.

BACKGROUND The reduced intensity of nonmyeloablative stem cell transplant (NMSCT) has enabled older patients to benefit from allogeneic therapy. Identification of suitable donors remains an obstacle. The use of alternative donors for stem cell therapy is essential to ensure broad applicability of allogeneic therapy. METHODS Clinical results using alternative hematopoietic stem cell donors are reviewed, including matched unrelated donors, partially matched family member donors, and unrelated partially matched umbilical cord blood. RESULTS The successful use of NMSCT in the treatment of hematologic and nonhematologic diseases has increased the number of patients capable of receiving allogeneic therapy. However, the stem cell donor pool remains limited due to the infrequent number of patients with matched siblings. CONCLUSIONS The use of alternative donor stem cell sources can expand the number of patients able to receive allogeneic therapy. Preliminary studies indicate that the use of alternative donors can provide reliable engraftment, although graft-vs-host disease remains a concern.