TGFB1 and systemic sclerosis: CD163 is one of the marker genes of M2 macrophages, plasma and urine samples from SSc patients contained significantly higher levels of sCD163 than HCs [44]; Compared to M1 macrophages, M2 macrophages secrete a large number of pro-fibrotic molecules such as TGF-β and VEGF (Fig. 2), which makes us shift our focus to M2 macrophages.