Increase in circulating stem cells following chemotherapy in man

Area of Science:

• Hematology
• Oncology
• Stem Cell Biology

Background:

• Chemotherapy often leads to myelosuppression, impacting cancer patient recovery.
• Granulocytic stem cells, or colony-forming units-culture (CFU-C), are crucial for hematopoiesis.
• Assessing CFU-C levels is vital for understanding treatment effects and recovery potential.

Purpose of the Study:

• To quantify circulating granulocytic stem cells (CFU-C) in cancer patients during intermittent chemotherapy.
• To evaluate the feasibility of collecting and cryopreserving peripheral blood stem cells.
• To explore the potential of autologous stem cell infusion for managing chemotherapy-induced myelosuppression.

Main Methods:

• In vitro methylcellulose technique used to determine CFU-C concentration.
• Leukopheresis employed for large-scale stem cell collection from peripheral blood.
• Cryopreservation methods assessed for stem cell recovery efficacy.
• Serial monitoring of CFU-C levels during chemotherapy cycles.

Main Results:

• Post-treatment CFU-C median concentration (23) was significantly higher than pre-treatment (6) in cancer patients (p < 0.001).
• Leukopheresis and cryopreservation achieved a high median CFU-C recovery rate of 99.5%.
• Cyclical increases in stem cell concentration, up to 20 times baseline, were observed.
• Peripheral blood apheresis can yield stem cell quantities comparable to bone marrow harvests.

Conclusions:

• Intermittent chemotherapy significantly mobilizes granulocytic stem cells into the peripheral circulation.
• Peripheral blood stem cell collection is an effective method for obtaining substantial numbers of CFU-C.
• Autologous stem cell infusion using mobilized peripheral blood stem cells is a potentially practical strategy to prevent myelosuppression in intensive chemotherapy regimens.