IL7 and rheumatoid arthritis: Elevated IL-7 levels are associated with multiple autoimmune disorders [20,22] and in vivo loss-of-function studies demonstrate critical pathogenic roles of IL-7 in a variety of autoimmune diseases, including inflammatory bowel disease [23-25], rheumatoid arthritis [20,21], type-1 diabetes [17,26] and experimental autoimmune encephalomyelitis [18].