Peripheral blood stem cell mobilization for high-dose chemotherapy

Several studies have clearly documented a more rapid hematopoietic recovery with growth factor-mobilized PBSC than with bone marrow. Time to engraftment for neutrophils and platelets average 8-12 days in contrast to 2-4 weeks after bone marrow. This rapid hematopoietic recovery with PBSC has decreased the duration of hospitalization, transfusion requirements, and costs. Although growth factors alone may mobilize enough PBSC for high-dose chemotherapy, administration of growth factor after submyeloablative chemotherapy increases the yield of CD34(+) cells. Based on the car rent data, CD34(+) cell content of PBSC appears to be the single most powerful predictor of hematopoietic recovery. Infusion of greater than or equal to 5 x 10(6) CD34(+) cells/kg is associated with a rapid engraftment of neutrophils and platelets, although successful engraftment has also been reported with infusion of 2.5-5 x 10(6) CD34(+) cells/kg. Age, prior radiotherapy,marrow involvement, and prior chemotherapy regimens are important factors influencing the yield of stem cells. Therefore, using these parameters, we may identify the patients who will fail to mobilize sufficient numbers of PBSC before collection and use new strategies for stem cell mobilization. Because of the ease of collection and rapid engraftment after myeloablative therapy, PBSC have replaced bone marrow for autologous transplantation and may supplant bone marrow for allogeneic transplantation in the near future.