TNF and rheumatoid arthritis: RA patients with active inflammation often describe their pain symptoms as ‘aching’, ‘sharp’, ‘tender’ or ‘tiring’ and ‘sickening’ according to the McGill pain Questionnaire148, The levels of inflammatory cytokines such as IL-1β, IL-6, TNF-α or growth factors such as vascular endothelial growth factor, nerve growth factor, or chemokine CCL2 are elevated in the RA synovium or synovial fluid.