Basal CD34+ Cell Count Predicts Peripheral Blood Stem Cell Mobilization in Healthy Donors after Administration of Granulocyte Colony-Stimulating Factor: A Longitudinal, Prospective, Observational, Single-Center, Cohort Study

- Granulocyte colony-stimulating factor-mobilized peripheral blood stem cells have been increasingly used for allogeneic transplantation and several factors have been reported as influencing healthy donor mobilization performance
- The number of CD34+ cells in the peripheral blood steady state may be a useful parameter for selecting allogeneic healthy donors

A longitudinal, prospective, observational, single-center, cohort study on healthy donors (HDs) was designed to identify predictors of CD34+ cells on day 5 with emphasis on the predictive value of the basal CD34+ cell count. As potential predictors of mobilization, age, sex, body weight, height, blood volume as well as white blood cell count, peripheral blood (PB) mononuclear cells, platelet count, hematocrit, and hemoglobin levels were considered. Two different evaluations of CD34+ cell counts were determined for each donor: baseline (before granulocyte colony-stimulating factor [G-CSF] administration) and in PB after G-CSF administration on the morning of the fifth day (day 5). A total of 128 consecutive HDs (66 males) with a median age of 43 years were enrolled. CD34+ levels on day 5 displayed a non-normal distribution, with a median value of 75.5 cells/µL. To account for the non-normal distribution of the dependent variable, a quantile regression analysis to predict CD34+ on day 5 using the baseline value of CD34+ as the key predictor was performed. On crude analysis, a baseline value of CD34+ ranging from .5 cells/µL to 1 cells/µL predicts a median value of 50 cells/µL on day 5; a value of 2 cells/µL predicts a median value of 70.7 cells/µL; a value of 3 cells/µL to 4 cells/µL predicts a median value of 91.3 cells/µL, and a value ≥ 5 predicts a median value of 112 cells/µL. In conclusion, the baseline PB CD34+ cell count correlates with the effectiveness of allogeneic PB stem cell mobilization and could be useful to plan the collection.