Myofibroblasts are induced by a number of cytokines, growth factors, and other agents present in SSc tissue or serum, including: TGF-β1, TGF-β3, IL-4, TNFα, IL-6, GMCSF, thrombin, bradykinin, histamine, tryptase, oncostatin M, IL-13, PDGF-β, ET-1, TLR 2/1 ligands, and the lysophospholipids, S1P and LPA (5, 353–355). Here, IL4 is linked to systemic sclerosis.