Activated macrophages are known to play an important role in the pathogenesis and progression of rheumatoid arthritis, primarily through the secretion of various inflammatory mediators, such as TNF-α and IL-6 etc. These pro-algesic cytokines stimulate the expression and release of neuropeptide from sensory neurons [39,40], thus, contributing to the genesis of inflammatory and neuropathic pain. The gene discussed is TNF; the disease is rheumatoid arthritis.