Transforming clinical apheresis waste into a renewable source of patient-derived CD34+ hematopoietic stem cell biobank for beta-hemoglobinopathy research and therapeutic discovery

Background aims

The development of next-generation therapies for sickle cell disease (SCD) and beta thalassemia (beta thal), including fetal globin–inducing small molecules and gene therapy approaches, depends on patient-derived CD34+ hematopoietic stem and progenitor cells (HSPCs) for discovery and preclinical validation, but commercial vendors stock only healthy donor material and disease-specific banks hold limited inventories. Recent US Food and Drug Administration and National Institutes of Health guidance favoring human cell-based methods over animal testing underscores the value of authentic patient cells. Methods: Over 14 months we recovered, purified, and biobanked CD34+ HSPCs from clinical apheresis product waste and mobilized peripheral blood (PB) otherwise discarded after clinical procedures, using immunomagnetic selection adapted for hemoglobinopathy specimens; a microfluidic technology was evaluated separately. We quantified yield and purity for bead-selected material and cell number and viability for the microfluidic pilot; engraftment was tested in NBSGW mice. Results: Immunomagnetic selection recovered a median of 4.71 × 10 ⁶ CD34+ cells from just 1 to 2 mL of apheresis product waste, comparable to the 6.0 × 10 ⁶ cells from a 10 to 40 fold larger volume of PB waste, with similar purity across sources and diagnoses. Because apheresis product waste is far more concentrated, it reaches equivalent yields without the density-gradient steps required for PB waste, approximately halving processing time. Recovered cells engrafted NBSGW mice, confirming preserved repopulating capacity. The microfluidic pilot (two patients, 11 specimens) recovered 2.17 × 10 ⁶ CD34+ cells per specimen at greater than 90% viability and purity. Conclusions: A center with existing apheresis infrastructure can reproducibly recover, bank, and distribute research-grade patient CD34+ HSPCs, addressing a recognized gap in the hemoglobinopathy pipeline.

Highlights

• Clinical apheresis waste is used to generate a single-center biobank of high-quality, research-grade CD34+ HSPCs from patients with sickle cell disease and beta-thalassemia.

• Concentrated apheresis waste matches large-volume PB waste in CD34+ yield and purity.

• Microfluidic enrichment recovers CD34+ cells at >90% viability and purity across 2 patients.

• Recovered CD34+ HSPCs engraft mice and form erythroid cells, preserving function.