TNF and rheumatoid arthritis: It is well established that patients with RA have elevated levels of inflammatory cytokines, specifically TNF-α, IL-1β, and IL-6, and are found directly at the synovial joint or found to be released into the plasma, stimulating both local and systemic inflammation (Saxne et al., 1988; Shingu et al., 1993; Chikanza et al., 1995).