Ex vivo treatment of neutrophils from patients with sepsis with G-CSF improves phagocytosis.77 However, clinical trials of G-CSF or GM-CSF in sepsis and or pneumonia have failed to replicate these results with no improvement in mortality78 79 or in specific neutrophil functions.80 In addition, use of G-CSF risks increasing neutrophilic inflammation; however, several large meta-analyses have not demonstrated a significant increase in adverse outcomes with G-CSF treatment.78 79. Here, CSF3 is linked to susceptibility to pneumonia measurement.