Race and Ethnicity Influences Collection of Granulocyte Colony–Stimulating Factor–Mobilized Peripheral Blood Progenitor Cells from Unrelated Donors, a Center for International Blood and Marrow Transplant Research Analysis

• There are racial/ethnic differences in baseline blood counts and response granulocyte colony–stimulating factor.
• Variations are seen in CD34+ cell collection efficiency among races/ethnicities.
• Differences in CD34+ cell collection are most pronounced in high body mass index donors.
• Racial/ethnic differences in CD34+ cell collection is independent of donor weight.

Little information exists on the effect of race and ethnicity on collection of peripheral blood stem cells (PBSC) for allogeneic transplantation. We studied 10,776 donors from the National Marrow Donor Program who underwent PBSC collection from 2006 to 2012. Self-reported donor race/ethnic information included Caucasian, Hispanic, Black/African American (AA), Asian/Pacific Islander (API), and Native American (NA). All donors were mobilized with subcutaneous filgrastim at an approximate dose of 10 μg/kg/day for 5 days. Overall, AA donors had the highest median yields of mononuclear cells per liter and CD34+ cells per liter of blood processed (3.1 × 109 and 44 × 106, respectively), whereas Caucasians had the lowest median yields at 2.8 × 109 and 33.7 × 106, respectively. Multivariate analysis of CD34+ per liter mobilization yields using Caucasians as the comparator and controlling for age, gender, body mass index, and year of apheresis revealed increased yields in overweight and obese AA and API donors. In Hispanic donors, only male obese donors had higher CD34+ per liter mobilization yields compared with Caucasian donors. No differences in CD34+ per liter yields were seen between Caucasian and NA donors. Characterization of these differences may allow optimization of mobilization regimens to allow enhancement of mobilization yields without compromising donor safety.