Estimation of the number of active HSPCs. (A) The estimated number of active, long-term-repopulating HSPCs, corresponding to the estimated granulocyte population size at last follow-up with a normalized Chao1 estimate (the Chao1 estimate divided by VCN for VCN >1; supplemental Methods). (B) The correlation between the number of active, long-term-repopulating HSPCs (Chao1 estimate of the size of the granulocyte population) and the number of corrected CD34⁺ cells infused per kilogram for each patient.