Peripheral Blood Stem Cells: Transplantation and Beyond

Peripheral blood stem cells are rapidly becoming a major source of hemopoietic stem cells for transplantation in patients with various hematological and oncological conditions. Clinical results of peripheral blood stem cell transplantation (PBSCT) have shown benefits of earlier hemopoietic recovery, lower morbidity, and greater cost-effectiveness compared with conventional bone marrow transplant. Moreover, the relative ease of obtaining large amounts of stem cells has made multicycle transplantation a viable option in the treatment of malignancies, allowing further escalation of chemotherapy dose intensity. The extension of PBSCT into the use of allogeneic and cord blood cells so far has been met with encouraging results, and the latter holds promise to increasing donor availability to patients requiring transplantation. Developments in cytokine research and ex vivo manipulation of hemopoietic stem cells are enabling new approaches to anticancer treatment involving tumor purging, immunomodulation, ex vivo expansion of stem cells and gene therapy. PBSCT may also become a therapeutic option in certain nonmalignant diseases. This review will discuss the current clinical practice and future developments in PBSCT.