On Day 0, the day of transplant, the recipient will receive the bone marrow stem cells collected from the donor. The collection may be either directly from the bone marrow, from umbilical cord blood, or from peripheral blood using a procedure called leukapheresis. The bone marrow stem cells are stored in a special blood transfusion bag and administered to the recipient in his or her room the same way a blood transfusion is given, through the central line. The infusion typically takes one to two hours to complete. The donor marrow stem cells travel in the bloodstream to the bone marrow space where they grow and mature.

Special Treatment of Marrow

In some cases, the bone marrow stem cells will be treated or processed before transplant. For example, if the donor is a parent or other close relative whose human leukocyte antigens (HLA) type is only partially matched with the recipient, the stem cells will be specially treated to enrich for stem cells, called CD34 positive cells, and remove the T cells responsible for graft-versus-host disease (GvHD). This process takes 10 to 12 hours to complete. The resulting stem cells usually fill one syringe and are administered through an IV by a doctor.

If the donor and recipient are HLA matched but have different blood types, the marrow is treated to remove most of the red blood cells and minimize a transfusion reaction. This process takes several hours to complete. The resulting marrow is slightly pink and is administered from a blood transfusion bag.

For autologous transplants or umbilical cord blood transplants, the marrow stem cells that have previously been collected, and frozen are thawed and administered as a blood transfusion in one or more blood bags. The chemical (DMSO) that is used to safely freeze the marrow, peripheral blood or umbilical cord blood has an unusual odor that you will notice within minutes of beginning the infusion. This odor, which will be on your child's breath, is harmless but will persist for several days. In addition, you may notice that your child's urine is red following the transplant. This is due to another chemical added to the marrow and is completely harmless.