IL-7, a member of the IL-2 family, is considered to affect aberrant immune activity in autoimmune diseases, such as diabetes and multiple sclerosis (Harrison et al. 2012; Harley et al. 2007), and chronic inflammatory diseases, such as rheumatoid arthritis (Hartgring et al. 2006), ankylosing spondylitis (Gracey et al. 2016), and inflammatory bowel disease (Anderson et al. 2011; Barata et al. 2019), by binding to IL-7R. The gene discussed is IL2; the disease is rheumatoid arthritis.