Randomized controlled trials have proven the efficacy of anti-TNFα agents in the treatment of rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, and fistulizing Crohn disease, and the clinical use of TNFα-targeted therapies in these diseases is now widespread.7 Infliximab, the most commonly used agent, is a chimeric monoclonal antibody composed of the variable region of a mouse antibody joined to the constant region of human IgG1. This evidence concerns the gene TNF and ankylosing spondylitis.