CCL18 and idiopathic pulmonary fibrosis: The CellChatDB analysis identified seven ligands (C–C motif chemokine ligand 18: CCL18, C–X–C motif chemokine ligand 9: CXCL9, C–X–C motif chemokine ligand 10: CXCL10, C–X–C motif chemokine ligand 11: CXCL11, interleukin 6: IL6, interferon gamma: IFNG, selectin E: SELE) in the 112 IPF-DEgenes (Table 1).