Because G-CSF was dramatically increased (~3–4 fold) in the sera of GKO mice, and G-CSFR is expressed predominantly by neutrophils and their progenitors in the BM, we depleted G-CSF using 3 doses of αG-CSF mAb to determine if reducing G-CSF levels could prevent neutrophilia and thus fatal encephalitis. The gene discussed is CSF3R; the disease is encephalitis.