TGFB1 and systemic sclerosis: Given the fibrotic features of SSc, we measured the expression of genes with roles in fibrosis, specifically Col1a1, ColIII, and Tgfb1, 2, and 3. Most importantly, we found that VSMCs responded to stimulation with purified SSc IgG by modulating the gene expression of TGF-β isoforms 1 and 2 (Fig. 4B, C).