Purpose of review: This article highlights and emphasizes how new knowledge of mechanisms linked to the interleukin-23 (IL-23)/IL-17 pathway is relevant to the pathophysiology of axial spondyloarthritis (axSpA) and demonstrates how molecules in IL-23/IL-17 pathway provide novel therapeutic targets for axSpA patients.
Recent findings: Similarly to ankylosing spondylitis (AS), the increased frequency of Th17 cells in nr-axSpA patients underscores the concept that these disorders can be viewed on a spectrum. Recent findings suggest that the contribution of IL-23/IL-17 signaling pathways possibly differs in male and female AS patients. The finding that IL-17 and IL-22 secreting-type 3 innate lymphoid cells are increased in AS patients point to their potential role in the pathogenesis of axSpA. Reports of dysbiosis in the gut microbiome of AS patients support previous work indicating a possible causal relationship between altered gut flora, ileocolonic inflammation and axSpA. Of important clinical relevance are results from clinical trials supporting the efficacy and safety of agents that block IL-12/23 (ustekinumab) and IL-17 (secukinumab and ixekizumab) in AS patients.
Summary: Recent studies further establish the central position of the IL-23/IL-17 pathway in the pathogenesis of axSpA. Targeting the IL-23/IL-17 pathway appears to be a safe and effective strategy for treatment of axSpA patients.