TNF and rheumatoid arthritis: Studies have reported that the Ins allele increases expression of NFkB[13] so, given that NFkB regulates numerous pro-inflammatory cytokines (including TNF-a, IL-1b, IL-6, or IL-7 involved in the activation and recruitment of inflammatory cells[18]), this inflammatory environment could lead to non-specific citrullination[31] that promotes the production of anti-CCP antibodies in RA patients.