CD274 and autoimmune disease: Indeed, PD-L1 expression is elevated in the inflamed tissues of a number of autoimmune diseases, including type 1 diabetes, autoimmune encephalomyelitis (EAE), Crohn’s syndrome, and rheumatoid arthritis29, 37, 38, and the tissue-infiltrating T cells in these autoimmune disorders express surface PD-138, 39, 40, 41.