The composition of leukapheresis products impacts on the hematopoietic recovery after autologous transplantation independently of the mobilization regimen.

BACKGROUND: Effects of mobilization regimen on the composition of leukapheresis products (LPs) and on hematopoietic reconstitution after autologous peripheral blood progenitor cell transplantation (PBPCT) are not well known. STUDY DESIGN AND METHODS: The effects of three different mobilization regimens--stem cell factor (SCF) plus granulocyte colony stimulating factor (G-CSF) plus cyclophosphamide (CCP), G-CSF alone, and G-CSF plus CCP--on the composition of LPs from patients with nonhematologic PBPC malignancies compared to LPs from G-CSF-mobilized healthy donors and normal marrow (BM) samples were analyzed. The impact of LP composition on both short- and long-term engraftment after autologous PBPCT was also evaluated.
RESULTS: The most effective regimen for mobilization of CD34+ hematopoietic progenitor cells (HPCs) into peripheral blood was SCF, G-CSF, and CCP, providing the highest numbers of all CD34+ HPCs subsets analyzed. Patients mobilized with SCF plus G-CSF plus CCP showed the highest numbers of neutrophils and monocytes, whereas the highest numbers of lymphocytes and NK cells were observed in LPs from G-CSF-mobilized patients. The overall number of CD34+ HPCs was the strongest factor for predicting recovery of platelets, whereas the number of myelomonocytic-committed CD34+ precursors was the most powerful independent prognostic factor for WBC and neutrophil recovery. The overall number of CD4+ T cells returned showed an independent prognostic value for predicting the occurrence of infections, during the first year after transplant.
CONCLUSIONS: The use of different mobilization regimens modifies the overall number of CD34+ HPCs obtained during leukapheresis procedures, and also affects both the absolute and the relative composition of the LPs in different CD34+ and CD34- cell subsets.