IL4 and systemic sclerosis: When searching for “systemic sclerosis” and cytokines in the PubMed database, TGF-β had the highest number of hits, followed by IL-6, IL-4, tumor necrosis factor (TNF)-α, platelet-derived growth factor, IL-10, IL-13, IL-1, IL-2, and IL-17 indicating cytokines are related to the pathogenesis of SSc.