Sudden termination of G-CSF injection leads to apoptosis of a large proportion of increased granulocytes

The effectiveness of granulocyte colony-stimulating factor (G-CSF) for gran ulocytopenia has been widely recognized. However, although granulocyte coun ts rapidly increase after a few injection of G-CSF, a large proportion of t he increased granulocytes disappear from peripheral blood within a few days following G-CSF withdrawal. Where do they go? In this report, the answer c an be seen at a glance. Using. MitoCapture and a CCD camera-equipped fluore scence microscope, we succeeded in demonstrating that G-CSF withdrawal indu ced loss of mitochondrial membrane potential, i.e., an early stage of apopt osis, in human peripheral granulocytes increased by G-CSF.