CXCR4 and idiopathic pulmonary fibrosis: Regarding human diseases, there is an increase in CXCL12 expression in lung epithelial cells and an elevated number of CXCR4-positive cells in IPF patients, suggesting that chronic injury in the epithelium induces the recruitment of CXCR4-positive cells such as SatMs and fibrocytes that may activate fibroblasts or act as sources for new fibroblasts [61].