Mobilized Peripheral Blood Stem Cells Collection, a Retrospective Review of the Impact of Race/Ethnicity Among Autologous and Allogeneic Donors: A Single Center Experience

Abstract

The impact of race/ethnicity on hematopoietic stem/progenitor cell (HSPC) mobilization remains controversial. Past studies have concluded Black healthy donors as more robust mobilizers or comparable mobilizers with Whites in response to granulocyte colony-stimulating factor (G-CSF). Whether ethnicity plays any role in HSPC mobilization in autologous donors was not studied. We conducted a single center retrospective study to examine effects of race/ethnicity on CD34+ cell mobilization both in allogeneic and autologous donors. Autologous donors included patients diagnosed with multiple myeloma (MM) and non-MM (non-Hodgkin's lymphoma, amyloidosis, POEM). Here we studied the self-reported race/ethnicity information and donor characteristics (63 autologous & 23 allogeneic). The donors were grouped as Black, White, Hispanic/Latino, and Asia Pacific Islanders (API). Both autologous and allogeneic donors received G-CSF for 5 days and plerixafor was administered on day 4/5 to autologous donors. Our data show that Black autologous donors had significantly higher CD34+ cell yield per liter blood in comparison to Whites and Hispanics respectively {mean ± SD (39.8 ± 23.9 vs. 24.3 ± 20.6 vs 22.5 ±16.1) × 106 CD34+ cells/liter, p=0.0184, n=63). Interestingly, the same trend was observed when we compared allogeneic donors (Black 45.1 ± 34.1 vs. White 20.2 ± 7.5 vs. Hispanic 47.1 ± 15.3) CD34+ cells/liter × 106, p=0.3699, n=23). The CD34+ cell yield between females and males among autologous or allogeneic donors was not statistically significant. Using multivariate analysis to evaluate CD34+ cell yields among different race/ethnicity, controlling for other variables in the model, autologous MM donors had the highest CD34+ cells yield than other groups (β_non-MM = −0.77, p- = 0.0003). Although Black MM donors had higher CD34+ cell yields than Whites or Hispanics, the CD34+ cell yields between the MM donors and healthy donors was surprisingly comparable both among Blacks and Whites. MM donors had higher CD34+ cell yields than any other groups. The above results support the view that therapies used in MM patients are likely more conducive of recovery of HSPCs. The superior CD34+ cell yields from MM patients in spite of lenalidomide-based therapies with known myelosuppressive potential is intriguing. Taken together, our study shows that MM patients display higher mobilizing ability than non-MM. Interestingly, when MM donors are compared with allogeneic donors, both Blacks and Whites retain comparable CD34+ cell yields. The increase in CD34+ cell yields in Blacks was more profound among autologous MM donors. The underlying biologic basis of higher CD34+ cell yields in Black donors warrants future investigation. Ongoing evaluation of donor characteristics and response to mobilization regimens would support development of novel strategies tailored to individual race/ethnicity groups in the future.