INTRODUCTION: In order to propose risk-adapted mobilization algorithms, several authors have tried to look for predictive factors of the CD34+ yield in healthy pediatric donors. Donor recipient body weight ratio (D/R ratio) was identified as one of the main variables related with the success to achieve the target cell dose for transplantation . According to this variable we modified the mobilization schedule . MATERIAL AND
METHODS: We report the results of 46 mobilizations and apheresis procedures performed in our center with unfavorable D/R ratio . Mobilization was attempted by the standard regime of G-CSF (10 mcg/kg/24 hours) in 28 cases (60.9 %), with high dose G-CSF (10 mcg/kg/12 hours) in 9 cases (19.6 %), and with plerixafor and G-CSF single dose regime in 9 cases (19.6 %).
RESULTS: CD34+ cell quantification before apheresis is closely related to CD34+ yield, being the only factor related to collected CD34+ cells (beta .71; P <.0001). The mobilization efficiency was higher in plerixafor group compared to the other two schedules (P <.0001). By using plerixafor for mobilization, we achieved the target CD34+ cell dose of ≥2 × 106 /kg per recipient body weight in all cases with unfavorable D/R ratio . It was observed that 17.4% of cases that not reached the established target cell dose were located in the standard or high-dose mobilization regimes . This difference is even greater for optimal collections (≥5 × 106 /kg), since of the 54.3% cases that did not reach this goal none was mobilized by plerixafor .
CONCLUSION: Tailoring the mobilization regime we can reach the target cell dose, even in those cases with the worst D/R ratio.