CXCL1 and hypersensitivity pneumonitis: Andrews et al. [24] reported that antigen-induced hypersensitivity pneumonitis (HP) pathology was accompanied by toll-like receptors (TLRs) 2- and 9-dependent induction/production of granulocyte colony-stimulating factor (G-CSF) that stimulates neutrophil production and recruitment of neutrophil chemokines, CXCL1, CXCL2, and CXCL5, into the airways.