Etoposide (VP-16) plus G-CSF mobilizes different dendritic cell subsets than does G-CSF alone

Area of Science:

• Immunology
• Hematology
• Cell Biology

Background:

• Dendritic cells (DCs) are crucial antigen-presenting cells for initiating anti-tumor immune responses.
• Two main DC subsets exist: myeloid DCs (DC1, CD11c+) and lymphoid DCs (DC2, CD123+, CD11c-).
• Peripheral blood progenitor cell (PBPC) mobilization with G-CSF alone in normal donors results in a predominance of DC2 cells.

Purpose of the Study:

• To investigate whether PBPC mobilization using chemotherapy in combination with G-CSF yields different DC subsets compared to G-CSF alone.
• To analyze the impact of different mobilization strategies on DC subset composition in patients undergoing autologous stem cell transplantation.

Main Methods:

• Analysis of DC subsets (DC1 and DC2) in apheresis products from 44 patients undergoing autologous stem cell transplantation.
• Patients received either G-CSF alone or etoposide plus G-CSF for progenitor cell mobilization.
• DC subsets were quantified, and the DC2/DC1 ratio was calculated.

Main Results:

• Patients receiving G-CSF alone mobilized significantly more total DC2 cells compared to those receiving etoposide plus G-CSF (median 6.2 x 10^6/kg vs 2.9 x 10^6/kg, P=0.001).
• The DC2/DC1 ratio was significantly higher in the G-CSF alone group (median 1.2) compared to the etoposide plus G-CSF group (median 0.4, P<0.001).
• These findings indicate distinct DC subset profiles based on the mobilization regimen.

Conclusions:

• The combination of chemotherapy (etoposide) plus G-CSF results in a different profile of mobilized dendritic cell subsets compared to G-CSF alone.
• G-CSF alone appears to be more effective in mobilizing lymphoid dendritic cells (DC2s) and maintaining a higher DC2/DC1 ratio.