Background: The combination of granulocyte-colony-stimulating factor (G-CSF [filgrastim]) and dexamethasone (G-CSF/dex) is an effective granulocyte mobilization regimen, but the variables that affect donor neutrophil response and granulocyte collection yield are not well characterized.
Study design and methods: A computerized database containing records of 1198 granulocyte collections from 137 unrelated volunteer apheresis donors during a 13-year period was retrospectively analyzed. Donors were categorized by age, sex, and cumulative number of granulocyte donations. Complete blood counts at baseline and after G-CSF/dex stimulation were recorded. The outcome variables include the preprocedure absolute neutrophil count (preANC), which reflects G-CSF/dex stimulation, and the granulocyte product yield per liter processed (BagGranYield/L).
Results: Higher baseline ANC and platelet (PLT) counts were significantly associated with higher preANC while a larger number of prior granulocytapheresis procedures was associated with lower preANC. Total filgrastim dose (used in weight-based dosing) did not significantly impact preANC or the granulocyte yield; weight-based dosing at 5 microg per kg and a uniform 480-microg dose produced equivalent preANC. PreANC and weight were the key determinants of granulocyte yield (BagGranYield/L).
Conclusion: Apheresis donors with higher baseline PLT counts and ANCs have higher ANCs after G-CSF/dex stimulation; donor age, weight, and sex do not have a significant impact. A uniform G-CSF dose of 480 microg is as effective as weight-based dosing at 5 microg per kg. Donor ANC monitoring should be considered after serial granulocytapheresis procedures.