In an investigation regarding the role of endotoxin in asthma onset, pretreatment of mouse exhibiting house dust mite (HDM)-induced asthma with endotoxin (LPS) reduced the migratory ability of dendritic cells and the expression of chemokine (C-C motif) ligand 20 (CCL 20), granulocyte macrophage colony-stimulating factor (GM-CSF), and interleukin-33 (IL-33) in airway epithelial cells, thereby improving eosinophilic inflammation and airway hyper-reactivity [52]. Here, CSF2 is linked to asthma.