TNF and rheumatoid arthritis: Accumulating evidences demonstrated that visfatin was identified as a proinflammatory adipocytokine and secreted extracellularly to upregulate inflammatory cytokines, such as TNF-α, IL-1β, IL-6 and CCL2 in rheumatoid arthritis synovial fibroblasts and monocytes in response to inflammatory stimuli [26,27].