CCL18 and systemic sclerosis: On the other hand, monocyte-derived macrophages (CD163+cells, CD206+cells) from SSc-ILD patients show M2 polarization and release TGF-β, IL-6, CCL-18 and osteopontin, that promote epithelial-to-mesenchymal transition (EMT), fibroblast-to-myofibroblast differentiation, and the progressive lung fibrotic process (21–25).