CXCR4 and idiopathic pulmonary fibrosis: Indeed, C-X-C Motif Chemokine Ligand 12 (CXCL12) acting on CXCR4 is activated during the acute exacerbation of IPF and other ILDs [72], while the matrix metalloproteases (MMPs), such as MMP1 and MMP7, exploit their role in the progression of IPF increasing epithelial cell proliferation and preventing their apoptosis [24,73].