Deficiency of IL-10 exacerbates autoimmune pathology in mouse models of systemic lupus erythematosus (SLE) (43), rheumatoid arthritis (RA) (44), and experimental autoimmune encephalomyelitis (EAE) (45), indicating the critical role of IL-10 in the regulation of immune homeostasis. This evidence concerns the gene IL10 and rheumatoid arthritis.