Does continuous flow apheresis influence viability in allogeneic hematopoietic stem cell harvest?

Area of Science:

• Hematology
• Transplantation Immunology

Background:

• Hematopoietic stem cell transplantation (HSCT) efficacy is linked to the quantity of viable CD34+ stem cells infused.
• G-CSF mobilization is a standard method to increase peripheral blood stem cells for collection.

Purpose of the Study:

• To evaluate the viability and apoptosis rates of CD34+ stem cells during G-CSF mobilized peripheral blood stem cell collection via continuous flow apheresis.
• To determine the impact of apheresis on the proportion of viable and apoptotic CD34+ cells.

Main Methods:

• Peripheral blood stem cells were collected from 17 healthy donors using continuous flow apheresis after G-CSF mobilization.
• Flow cytometry was employed to analyze cell populations, specifically assessing viability (Annexin V-FITC(neg)/7-AAD(neg)) and early apoptosis (Annexin V-FITC(pos)/7-AAD(neg)) in CD45(dim)CD34+ cells.

Main Results:

• The median viability of CD34+ stem cells in peripheral blood before apheresis was 97.7%, and in apheresis products, it was 97.3%.
• A statistically significant increase in early apoptotic CD34+ cells was observed post-apheresis (median 2.6%) compared to pre-apheresis (median 1.5%).
• Despite an increase in apoptosis in granulocytes and CD34+ cells, the overall viability of stem cells remained high in the apheresis product.

Conclusions:

• Continuous flow apheresis effectively collects viable CD34+ stem cells for transplantation.
• While apheresis leads to a slight, statistically significant increase in early apoptotic CD34+ cells, overall cell viability is well-preserved.
• The findings support the safety and efficacy of this apheresis method for obtaining stem cell grafts.