CSF3 and neutropenia: Recombinant human granulocyte colony-stimulating factor(rhG-CSF) is a hematopoietic cytokine approved in 1991 by the FDA(Filgrastim) for the treatment of chemotherapy-induced neutropenia.1 Human G-CSF is a glycoprotein mainly producedby the stromal cells of bone marrow during granulopoiesis.