IL1B and rheumatoid arthritis: In addition, NF-κB is a pleiotropic transcription factor that significantly upregulates the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17) in the synovial joint resulting in the increased expression of RANKL (receptor activator of nuclear factor-kB ligand), which in turn stimulates macrophages to participate in osteoclastogenesis resulting in bone destruction in RA (21, 22).