TNF and rheumatoid arthritis: Levels of inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukin-1-beta (IL-1β) and IL-6 [1-3] are increased in arthritic joints, whereas high levels of angiogenic factors such as vascular endothelial growth factor (VEGF) [4,5] and gliostatin (GLS) [6,7] have been reported in synovial fluid and sera from patients with RA.