IL13 and systemic sclerosis: The release of reactive oxygen species (ROS) (3) as well as the secretion of chemokines and growth factors, i.e., platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β), connective tissue growth factor (CTGF), interleukin-6 (IL-6), and interleukin-13 (IL-13), all significantly higher in SSc patients than in controls (1–3), can promote fibroblast activation, fibroblast to myofibroblast transition, and collagen deposition in fibrosis (4).