The mechanistic link between human leukocyte antigen B27 (HLA-B27) and ankylosing spondylitis (AS) is one of the great enigmas in rheumatology. The introduction of biological therapies that target tumor necrosis factor (TNF) or the interleukin (IL) 23/IL-17A axis has had a major impact on the quality of life for many patients with AS, and one…
