Correction of neutropenia with rHuG-CSF after loss of response to rHuGM-CSF following autologous bone marrow transplant.

We describe a patient who presented with graft failure following autologous BMT, with an initial response of the neutrophil count to rHuGM-CSF but eventual loss of this response. Subsequently, this patient responded to rHuG-CSF. This could be explained by the fact that rHuG-CSF stimulates both early and late myeloid progenitor cells whereas rHuGM-CSF stimulates mainly the intermediate myeloid progenitor cells. This finding suggests that rHuG-CSF should be investigated for the treatment of patients with graft failure following ABMT.