[Recent trend in G-CSF therapy and clinical laboratory tests]

Granulocyte colony-stimulating factor (G-CSF) has strong leukopoietic activity and it is used for patients with leukopenia during leukemia chemotherapy. However, some leukemia cells show a high affinity to G-CSF and are driven to proliferative phase. In our laboratory, we developed two testing methods. 1) Flow cytometric method on G-CSF susceptibility of leukemia cells using FITC-labeled G-CSF, and 2) Immunohistochemical method for detecting the ratio of cells driven from dormant phase to proliferative phase by G-CSF with anti-PCNA antibody and Ki-67 antibody. In MDS patients G-CSF administration induced an increase of cells in proliferative phase. The patients treated with cytosine arabinoside following G-CSF showed hematologically good improvement. A new mode of therapy using G-CSF in combination with other cytokines or antileukemic agents will be developed in the near future for treatment of leukemia patients.