IL-33 and sST2 levels were increased in the serum of SSc patients.  IL-33 levels were correlated with skin lesions, degree of sclerosis.  IL-33 polarized M2 macrophages to produce TGF-β1 and IL-13, induced ILC2 proliferation, increased eosinophils and the level of IL-13, and induced Treg dysfunction. This evidence concerns the gene IL33 and systemic sclerosis.