Upon infection or other inflammatory stimuli, niche populations modulate the hematopoietic response by enhancing the release of granulocyte colony-stimulating factor (G-CSF) and IL-6, in order to promote the proliferation and differentiation of myeloid progenitors (emergency myelopoiesis), whereas the expression of CXCL12 and KIT ligand is downregulated. The gene discussed is CSF3; the disease is infection.