ICOS and autoimmune disease: The single nucleotide polymorphisms (SNP)s, rs3087243, rs231725, rs11571302, and rs11571297, located in the CTLA4-ICOS intergenic region were identified in predisposition to autoimmune diseases including rheumatoid arthritis [2], vitiligo [3], hypothyroidism [4, 5], type 1 diabetes [6–10], and Graves’ disease [11] by GWASs.