TNF and rheumatoid arthritis: Adipose tissue has an endocrine function because it secretes many molecules (adipokines) involved in the inflammatory network and other pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin-1 (IL-1), monocyte chemotactic protein 1 (MCP-1) and interleukin-6 (IL-6) involved in RA pathogenesis.