Basal CD34+ Cell Count Predicts Peripheral Blood Hematopoietic Progenitor Cells Mobilization in Healthy Donors after Administration of G-CSF

BACKGROUND: Peripheral blood (PB) hematopoietic progenitor cells (HPC) mobilized with G-CSF are the first-choice source for allogeneic stem cell transplantation. We carried out a prospective study on healthy donors (HDs), to identify donor characteristics that could influence the effectiveness of mobilization.

STUDY DESIGN AND METHODS: PB-HPC allogeneic donations from sibling HDs were analyzed. We tested somatic variables (sex, age, weight, height, volemia) and blood counts (WBC, platelets, hemoglobin, CD34+ cell count). Two different determinations of CD34+ cells were done in each HD: baseline (before G-CSF administration) and in PB on the morning of the fifth day (after G-CSF administration). HDs received G-CSF subcutaneously at a dose of 10 µg/kg per day.

RESULTS: 128 consecutive HDs (66 males) with a median age of 43 years were enrolled. The mean value of CD34+ on day 5 was 90.8 cells/µL, 84.2 cells/µL in females and 97.2 cells/µL in males. The median values of CD34+ on day 5 were 75.5 cells/µL for the overall sample, 74 cells/µL in females and 80 cells/µL in males. On univariate correlation analysis, donor weight r=0.19, P<0.05, height (r=0.20, P<0.05), volemia (r=0.18, P<0.05) and baseline CD34+ (r=0.38, P<0.001) were significant predictors of CD34+ on day 5. Data analysis by gender showed that CD34+ on day 5 were predicted by age (r=-0.30, P<0.05), baseline WBC (r=0.25, P<0.05), baseline CD34+ (r=0.31, P<0.05) in males and by baseline CD34+ (r=0.45, P<0.001) in females. We performed two multivariate analyses either by using ordinary regression (to predict the mean value of CD34+ on day 5) or median regression (to predict the median value of CD34+ on day 5) according to the values of CD34+ at baseline (see table) in the whole study population and separately in females. These results indicate that in the whole study population and by using ordinary regression, a baseline value of CD34+ ranging from 0.5 to 2 cells/µL predicts a mean CD34+ value of 75.7 cells/µL at 5 days whereas a baseline value of CD34+ ≥3 cells/µL predicts a mean CD34+ value of 107.5 cells/µL at 5 days. Furthermore, in the whole study population but by using the median regression, a baseline value of CD34+ ranging from 0.5 to 2 cells/µL predicts a median CD34 + value of 64.6 cells/µL on day 5 whereas a baseline value of CD34+≥3 predicts a median CD34 value of 101.1 cells/µL on day 5.

CONCLUSIONS: Baseline, HDs PB CD34+ cell counts correlated with the effectiveness of allogeneic HPC mobilization and could be useful to plan the collection.

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