Predictors for successful PBSC collection on the fourth day of G-CSF-induced mobilization in allogeneic stem cell donors

Peripheral blood stem cells (PBSCs) used for allogeneic transplantation are collected by apheresis after pre-treatment of donors with G-CSF. Using modern apheresis devices stem cells can be collected more efficiently. It was studied whether collection on the 4th instead of the 5th day after initiation of G-CSF treatment might be feasible. Stem cell yields that could have been collected on day 4 were calculated in two cohorts treated with 10 mu g/kg G-CSF once daily (n=106, cohort I) or 5 mu g/kg twice daily schedule (n=85, cohort II). Harvests were predicted using the median collection efficiency (CE) of the apheresis machine and regarded successful when>5.0 x10(6) CD34(+/)kg recipient body weight. Successful harvests at day 4 could have been obtained in only 22.6% and 41.2% of donors in cohort I and II respectively, while the expected successful collections on day 5 were 55.7% and 76.5%. Individual donor factors that correlated with a successful harvest on day 4 were weight, BMI, age, ratio donor/recipient weight and total G-CSF dose in cohort I, whereas ratio donor/recipient weight was the only significant predictor in cohort II. Donor weight, BMI and total G-CSF dose correlated positively with CD34(+) values in the blood on day 4 in all donors. However, donor characteristics were not able to be used as strong predictors in daily practice. In conclusion, PBSC collection on day 4 will not result in a successful harvest in most stem cell donors, however using a twice daily G-CSF scheme increases the yield.