Oral administration of EGCG to RA-induced mice showed anti-inflammatory effects by decreasing inflammatory cytokines (IFN-γ, IL-6, TNF-α, and IL-1β) and altering immune cell populations, with increasing Treg cells in indoleamine 2,3-dioxygenase (IDO)-expressing dendritic cells [41]. This evidence concerns the gene IL6 and rheumatoid arthritis.