Mobilization efficiency of CD34⁺ cells in mobilized stem cell donors. The y-axis shows mobilization efficiency of blood CD34⁺ cells ([CD34⁺_{count_mobilized} – CD34⁺_{count_baseline}]/CD34⁺_{count_baseline}) expressed as cells per microliter, which represents the relative change from individual baseline blood CD34⁺ cell levels. Absolute count of CD34⁺ cells per microliter was defined as follows: average concentration of cells in volumetric counting by cytometer BioRad ZE5 × (frequency of total/100). Frequency of total was defined as percentage of CD34⁺45^low cells of total cells. In the x-axis, donors with rs772557-G allele (G/G) were compared with donors with the rs772557-A allele, both homozygous (A/A) and heterozygous (A/G). Colored data points represent rs772557 genotype groups: red, rs772557-G (G/G) homozygous; blue, rs772557-A allele (A/A) homozygous; and green, rs772557-A/G heterozygous. (A) Mobilization efficiency allogeneic donors (n = 31; P = .0214; 95% confidence interval [CI], 0.064-24.7). (B) Mobilization efficiency in autologous donors (n = 56; P = .1077; 95% CI, –7521 to 2279).