For example, the IL‐1 gene cluster was related to increase the risk of ankylosing spondylitis (Maksymowych et al., 2006); inhibiting the IL‐1 could reduce cartilage damage in rheumatoid arthritis (Strand & Kavanaugh, 2004); and the recently discovered IL‐33 as an IL‐1 cytokine family member has been proved to be specifically released from osteonecrotic bones (Saidi et al., 2011). This evidence concerns the gene IL1B and ankylosing spondylitis.