Factors affecting PBSC mobilization and collection in healthy donors

Peripheral blood stem cells are widely used as stem cell source for allografting. Progenitor cells can be effectively mobilized into peripheral blood in majority of healthy donors with a brief administration of G-CSF. A mobilization course in 111 donors (median age 40 years) was retrospectively studied and the factors influencing the efficacy of mobilization were analyzed. The median number of CD34+ cells per kg recipient weight 5.1 × 106 was obtained after a median of two aphereses. The target cell dose (⩾4.0 × 106/kg) was reached in 69% of donors. Circulating CD34+ count and CD34+ yield were negatively associated with donor's age. Other independent factors associated with superior yield were precollection platelet and WBC counts. In multivariate analysis only CD34+ precount predicted for CD34+ yield. G-CSF had an acceptable short-term safety profile. Our data confirm that apheresis is a safe procedure in healthy including aged donors and suggest that older donors could be poorer mobilizers than younger.