The use of peripheral stem cell support of high-dose chemotherapy.

Blood-derived stem cells are a functionally equivalent alternative to marrow-derived stem cells when autotransplanted to restore hematopoiesis that has been iatrogenically ablated. This alternate source of stem cells is particularly useful for patients who are candidates for marrow-ablative therapy and who also have bone marrow abnormalities that make it an unsuitable product for transplantation. When autologous blood-derived stem cells that were collected while their numbers were deliberately expanded in the circulation (mobilized) are transplanted, the resultant recovery of marrow function is very rapid. Because autologous bone marrow transplantation alone cannot result in hematopoietic recovery that is as rapid, peripheral stem cells have been preferred to bone marrow for autografting in some patients. This early recovery involves not only granulocytes but also platelets and red cells. Currently available cytokines administered at the time of ABMT usually facilitate only rapid granulocyte recovery. Emerging studies indicate that other consequential benefits of peripheral stem cell infusion that have not yet been fully recognized may exist. If, ultimately, techniques are developed that produce optimal stem cell mobilization for every eligible patient, then perhaps peripheral stem cell collections can be completed in 1 to 2 days. These cells could be used to minimize or ameliorate the hematopoietic toxicity associated with myelotoxic therapy. Perhaps then the technique eventually will become a routine adjunct to chemotherapy administration.