It is shown that elevated serum levels of pro-inflammatory cytokines such as Interleukins (IL) 1, 2, 6, 8, and tumor necrosis factor (TNF) alpha in chronic inflammatory states can stimulate leptin secretion [15, 21] and leptin itself can increases the production of inflammatory cytokines that are important in pathogenesis of RA [9, 22, 23] and assumably creates a complex cycle connecting metabolism and inflammation [7]. This evidence concerns the gene LEP and rheumatoid arthritis.