A new study has shown that the generation and collection of peripheral blood stem cells (PBSC) using an intensified granulocyte colony stimulating factor (G-CSF) conditioning regimen can be safe and well tolerated among haploidentical relatives of patients with sickle cell disease (SCD).

The study, published in the European Journal of Haematology, notes that these sickle cell trait donors can be a valid alternative source of peripheral CD34+ stem cells for T-cell depleted haploidentical stem cell transplantation (HSCT).

“Within our in vitro T-depleted haplo-identical HSCT trial for patients with high-risk SCD and no available sibling donor, we compared in this retrospective analysis the safety and efficacy of PBSC mobilization with a G-CSF intensified mobilization regimen in healthy and sickle cell trait donors,” the authors wrote.

The research team enrolled 13 healthy allogeneic peripheral stem cell donors and 19 sickle cell trait donors from their haplo-HSCT program. Stem cell mobilization was conducted using G-CSF for 5 days. Donors in the healthy group received 10 μg/kg G-CSF subcutaneously for at least 5 days.

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For the intensified G-CSF regimen, the sickle cell trait donors received 10 μg/kg G-CSF for the first 3 days and then 15 μg/kg 1 day before apheresis. On the fifth and last day of apheresis, the last dose (10 μg/kg) was given about 3 h prior to stem cell collection.

The results showed that in both sickle cell trait and healthy donors, high yields of CD34+ stem cells were obtained. Adverse events were similar in both groups during the G-CSF mobilization process, and no sickle cell-related complications were observed in the sickle cell trait group.

Given that the only curative treatment for SCD is HSCT with bone marrow from a human leukocyte antigen-matched sibling, and the availability of such donors is less than 20%, this new approach could help fill an urgently unmet need in this patient population.


Mohrez, M, Troeger, A, Kleinschmidt, K, et al. Feasibility of peripheral blood stem cell collection from sickle cell trait donors with an intensified G-CSF regimenEur J Haematol. Published online August 27, 2023. doi:10.1111/ejh.14083