IL23R and ankylosing spondylitis: However, IL-17A belongs to an immune axis with IL-23 (Gaffen et al., 2014) and the association of a variant (rs11209032) ∼15 kb downstream of the gene encoding the IL-23 receptor (IL23R) with ankylosing spondylitis (Burton et al., 2007) thus provided a rationale for repositioning secukinumab to treat this additional inflammatory disease.