TGFB1 and systemic sclerosis: It has been found that IL-17A reduces the expression of alpha-smooth muscle actin induced by TGFβ in human fibroblasts and that the number of Th17 cells in skin of SSc patients inversely correlates with skin fibrosis 30; further, it has been described that IL-17A suppresses type I collagen synthesis in SSc fibroblasts 6.