Conditioning begins the actual transplantation process. This term refers to the pre-transplantation phase in which patients undergo high-dose chemotherapy and/or radiation therapy to destroy their diseased marrow and blood stem cells. This step kills the body’s normal immune system reaction so that it won’t reject the healthy blood or marrow cells that are transplanted as foreign bodies. These transplanted cells should then go through engraftment within 30 days and begin producing new, normal blood stem cells.
Conditioning may sometimes be done in the Blood and Marrow Transplant Program Outpatient Transplant Unit. The patient must take extra care during this period to avoid exposure to germs and other infectious agents, since conditioning cripples the body’s immune system function.