The "G-CSF test": The response to a single dose of granulocyte colony-stimulating factor predicts mobilization of hemopoietic progenitors in patientswith hematologic malignancies

A significant proportion of patients with hematologic malignancies fail to mobilize sufficient hemopoietic progenitor cells (HPC), thereby restricting wider application of autologous transplantation. It would be of considerab le use to develop a test that could be used prospectively to assess an indi vidual patient's capacity to mobilize HPC. Twenty-two patients with lymphom a, myeloma, and chronic lymphocytic leukemia were given a single dose of 12 mu g/kg SC of granulocyte colony-stimulating factor (G-CSF), Blood colony- forming unit granulocyte-macrophage (CFU-GM) and CD34(+) cells were scored prior to the test dose, and 72, 96, and 120 hours later. The patients were then mobilized with a standard cyclophosphamide and G-CSF regimen and had b lood stem cells harvested. Patients were categorized as good, poor, or inte rmediate mobilizers on the basis of the CFU-GM/CD34(+) cell harvest content and the number of aphereses required to reach established threshold counts . The outcome of cyclophosphamide/G-CSF mobilization was correlated with th e response to the test dose of G-CSF. Good mobilizers had significantly hig her peak CFU-GM values and CFU-GM increment in response to the test dose pf G-CSF compared to intermediate and poor mobilizers. A peak CFU-GM count of greater than or equal to 250/mL identified the good mobilizers; conversely , all poor mobilizers had a peak CFU-GM count of <102/mL. An increment in C D34(+) cells counts of greater than or equal to 2.5/mu L was only observed in good mobilizers. The "G-CSF" test is a reliable test that can be used su ccessfully for the assessment of mobilizable HPC in patients with hematolog ic malignancies. It can also be used to stratify patients enrolled in trial s of mobilizing agents. (C) 1999 International Society for Experimental Hem atology. Published by Elsevier Science Inc.