CC-chemokine ligand 18 (CCL18) is another molecule produced by alveolar macrophages prompting the collagen production by lung fibroblasts; in patients with IPF, high baseline serum CCL18 concentrations (>50 ng/mL) were predictors of mortality and correlated with an acceleration of the disease [59]. This evidence concerns the gene CCL18 and idiopathic pulmonary fibrosis.