Cells of the innate and adaptive immune system elaborate a variety of cytokines and chemokines in addition to TGF-β and IL-4 (such as IL-6, PDGF, IL-1, IL-13, IL-17, IL-5, MCP-1, and CTGF) that have been found to be increased in serum or in tissues in which excess connective tissue matrix is accumulating in SSc. Here, IL17A is linked to systemic sclerosis.