Transplants of Hematopoietic Stem Cells

They reside in the bone marrow and often bone marrow is harvested to secure them. However, a few infusions of granulocyte colony-stimulating factor (G-CSF) — available thanks to recombinant DNA technology — causes them to be released into the blood where they can more easily be collected.

• multiple myeloma, a cancer of plasma cells;
• leukemia
• breast and some other cancers.

High doses of chemotherapy and radiation can be used to kill off the cancerous cells in a patient, but they also destroy the patient's bone marrow, and the patient will die without a transplant of hematopoietic stem cells.

These can be:

• autologous — from marrow that was
  • removed from the patient before cancer therapy began,
  • stored alive,
  • and, if there were cancer cells in the bone marrow (the case with multiple myeloma and leukemias), treated to "purge" the marrow of them. Most failures of autologous marrow transplants occur because of failure to get all the cancer cells out of the harvested marrow rather than failure to eliminate them from the patient.
• allogeneic — hematopoietic stem cells removed from someone else, usually a close relative. Allogeneic stem cells
  • avoid the problem of lurking residual cancer cells but
  • must be closely matched to the major histocompatibility loci (MHC) of the patient. If not, the donor cells will attack the recipient causing often-fatal graft-versus-host disease (GVHD). (Even with an exact match at the MHC, some GVHD is likely [Link].)

So hematopoietic stem cell transplants (HSCT) can be life-saving but create their own problems. (Another example: an "immediate"-type allergy like hay fever or asthma of the donor can create the same allergy in the recipient.)