The activation of monocytes to monocyte-driven alveolar macrophages (MoAMs) playing an important part in lung fibrosis because alveolar macrophages, especially MoAMs, express elevated levels of profibrotic genes such as CD163, MERTK (Tyrosine-protein kinase Mer), LGMN (Legumain), MMP9, TGF-β, TGF-β1, NRP1, and MRC1 (Mannose Receptor C-Type 1) [16]. Here, LGMN is linked to pulmonary fibrosis.