Spine and Rheumatic Diseases

Figure 1

Development and pathogenesis of spondyloarthritis (SpA). Patients of SpA need a genetic background, such as HLA-B27, B60, ERAP-1, and IL23R. After being triggered by environmental factors, such as infection or mechanical trauma, the immune dysregulation and inflammation occurred in enthesis through Th17 and Th1 immune reaction. With different genetic backgrounds and environmental factors, patients may have different phenotype, such as ankylosing spondylitis, psoriatic arthritis, or inflammatory bowel diseases. AS: ankylosing spondylitis; nr-ax SpA: nonradiographic axial spondyloarthritis; PsA: psoriatic arthritis; ReA: reactive arthritis; IBD: inflammatory bowel diseases.