Granulocyte colony-stimulating factor in acute myeloid leukemia

Area of Science:

• Hematology
• Oncology
• Cell Biology

Background:

• Recombinant human granulocyte-colony stimulating factor (G-CSF) use in acute myeloid leukemia (AML) is debated due to potential leukemic cell stimulation.
• Predicting in vivo leukemic proliferation using in vitro assays after G-CSF administration is crucial for patient management.

Purpose of the Study:

• To investigate if in vitro assays can predict in vivo leukemic proliferation in AML patients receiving G-CSF.
• To determine the correlation between G-CSF administration and leukemic resurgence.

Main Methods:

• Analyzed leukemic blasts from 30 AML patients (14 G-CSF group, 16 control).
• Assessed in vitro G-CSF-induced proliferation, [3H]thymidine incorporation, and colony formation.
• Measured G-CSF receptor affinity (Kd) and number on leukemic blasts.
• Performed immunophenotyping of blasts.

Main Results:

• Leukemic resurgence occurred in 9/14 G-CSF patients and 11/16 control patients.
• In vitro proliferation assays did not predict in vivo resurgence.
• Leukemic resurgence was associated with higher G-CSF receptor affinity (lower Kd) and lower receptor numbers per cell.
• No significant differences in blast immunophenotyping between resurgence and non-resurgence groups.

Conclusions:

• In vitro leukemic blast responsiveness to G-CSF does not predict in vivo resurgence in AML patients.
• Leukemic resurgence during G-CSF therapy is associated with leukemic blasts having fewer high-affinity G-CSF receptors.
• Blast phenotyping did not correlate with leukemic resurgence.