In chronic inflammatory diseases, high concentrations of TNFα are produced, leading to excessive inflammation and damage to the body.28,50 For example, children with JIA or inflammatory bowel disease exhibit high levels of pro-inflammatory cytokines in peripheral blood, synovial fluid, or gastrointestinal mucosa.28,50 Anti-TNFα drugs prevent excessive inflammation and the consequent tissue damage.50 This evidence concerns the gene TNF and juvenile idiopathic arthritis.