Microbial messaging to the marrow

In this issue of Blood, Boettcher et al demonstrate that endothelial cell-intrinsic MyD88 signaling is critical for synthesis of the cytokine granulocyte colony-stimulating factor (G-CSF) and induction of emergency granulopoiesis during gram-negative bacterial infection. ¹ This work answers long-standing questions centered on which cell types transform systemic pathogen signals into the molecular cues needed to elicit neutrophil generation in demand situations