Elevated amounts of IL-21 have subsequently been reported in many autoimmune diseases, including type 1 diabetes (King et al. 2004; McGuire et al. 2009), rheumatoid arthritis (Young et al. 2007; Sglunda et al. 2014), systemic lupus erythematosus (Ozaki et al. 2004; Bubier et al. 2009), Sjogren’s syndrome (Kang et al. 2011), inflammatory bowel diseases (Monteleone et al. 2005; Fina et al. 2008), and primary biliary cholangitis (PBC) (Wang et al. 2015). The gene discussed is IL21; the disease is autoimmune disease.