These results in preliminary small-scale laboratory culture suggest that the combination of SCF, Flt3-L and G-CSF should be investigated for development of protocols suitable for clinical scale-up and GMP compliance, as a possible cost-effective means of reducing neutropenia following autologous PBSC transplant which is not addressed by availability of donor granulocyte transfusion. The gene discussed is FLT3LG; the disease is neutropenia.