About this Research Topic
Spondyloarthritis (SpA) is a group of inflammatory rheumatic diseases sharing several features, including genetic predisposition, often associated with the HLA-B27 haplotype, and clinical manifestations marked by inflammation of peripheral joints and axial skeleton. Moreover, extra-articular manifestations involving the gut, eyes, and skin may present clinically in SpA. Based on the predominant clinical manifestation, SpA can be divided into two sub-types: peripheral SpA and axial SpA. The latter subtype includes patients who have already developed structural damage on X-ray, termed radiographic axial SpA, and patients who have experienced only inflammation without bone changes, termed non-radiographic axial SpA, which may be detectable with magnetic resonance imaging. The classification for axial SpA can be challenging as axial involvement may manifest itself variably from clinical and imaging perspectives in the heterogenous group of SpA. This aspect may be somewhat attributable to the distinctive and complex pathogenic mechanisms that may affect treatment responses.
Unlike other systemic autoimmune diseases, the innate immune system in SpA has a pivotal role marked by abnormal activity of innate immune cells, including γδ T cells, type 3 innate lymphoid cells, neutrophils, and mucosal-associated invariant T cells, at tissue-specific sites prone to the disease. In this context, enthesitis, inflammation of the entheses, is a crucial feature of SpA, although our current understanding of enthesitis pathophysiology is limited. Other cytokines, such as IL-23 and IL-17 are believed to have a critical role in SpA pathogenesis, activating the inflammatory process at the enthesis site. Additionally, gut inflammation is strongly related to SpA, demonstrated by the high prevalence of inflammatory bowel disease and the occurrence of subclinical gut inflammation in patients with SpA. The gut–joint crosstalk in SpA pathogenesis is further strengthened by resemblances in immunopathogenesis at both anatomical sites and by the clinical response to biologic drugs such as anti-TNF and anti-IL23 in IBD and certain forms of SpA. The therapeutic armamentarium for spondyloarthritis has recently been expanding after a gap of several years since TNF inhibitors were approved. Two new classes of drugs, anti-IL-17 and JAK inhibitors, with distinct mechanisms of action, have now been approved for managing patients with SpA.
Despite significant progress, there are still hurdles that need to be overcome to improve disease management, including the discovery of new biomarkers for diagnosis and disease activity assessment. A better understanding of the pathogenic pathways, and the identification of treatment-response factors could also improve currently employed treatment strategies. This Research Topic aims to expand the current understanding of the pathogenesis of SpA, and to further investigate clinical heterogeneity, particularly in axial SpA,
We, therefore, welcome the submission of original research, review, mini-review, hypothesis, and perspective articles that cover, but are not limited to, the following sub-topics:
• Pathomechanisms, including innate and adaptive immunity, involved in spondyloarthritis
• Insights into the pathophysiology of enthesitis
• The gut–joint crosstalk in spondyloarthritis pathogenesis
• Immune signatures associated with drug response
• New biomarkers for diagnosis and disease activity assessment
• Clinical, radiological, and gender differences related to axial spondyloarthritis
• New frontiers in imaging techniques in axial spondyloarthritis
• Treatment-response factors related to spondyloarthritis
• Current and upcoming treatment related to spondyloarthritis
• Next therapeutic target in spondyloarthritis
The Topic Editors declare no competing interests with regard to the Research Topic subject.
Unlike other systemic autoimmune diseases, the innate immune system in SpA has a pivotal role marked by abnormal activity of innate immune cells, including γδ T cells, type 3 innate lymphoid cells, neutrophils, and mucosal-associated invariant T cells, at tissue-specific sites prone to the disease. In this context, enthesitis, inflammation of the entheses, is a crucial feature of SpA, although our current understanding of enthesitis pathophysiology is limited. Other cytokines, such as IL-23 and IL-17 are believed to have a critical role in SpA pathogenesis, activating the inflammatory process at the enthesis site. Additionally, gut inflammation is strongly related to SpA, demonstrated by the high prevalence of inflammatory bowel disease and the occurrence of subclinical gut inflammation in patients with SpA. The gut–joint crosstalk in SpA pathogenesis is further strengthened by resemblances in immunopathogenesis at both anatomical sites and by the clinical response to biologic drugs such as anti-TNF and anti-IL23 in IBD and certain forms of SpA. The therapeutic armamentarium for spondyloarthritis has recently been expanding after a gap of several years since TNF inhibitors were approved. Two new classes of drugs, anti-IL-17 and JAK inhibitors, with distinct mechanisms of action, have now been approved for managing patients with SpA.
Despite significant progress, there are still hurdles that need to be overcome to improve disease management, including the discovery of new biomarkers for diagnosis and disease activity assessment. A better understanding of the pathogenic pathways, and the identification of treatment-response factors could also improve currently employed treatment strategies. This Research Topic aims to expand the current understanding of the pathogenesis of SpA, and to further investigate clinical heterogeneity, particularly in axial SpA,
We, therefore, welcome the submission of original research, review, mini-review, hypothesis, and perspective articles that cover, but are not limited to, the following sub-topics:
• Pathomechanisms, including innate and adaptive immunity, involved in spondyloarthritis
• Insights into the pathophysiology of enthesitis
• The gut–joint crosstalk in spondyloarthritis pathogenesis
• Immune signatures associated with drug response
• New biomarkers for diagnosis and disease activity assessment
• Clinical, radiological, and gender differences related to axial spondyloarthritis
• New frontiers in imaging techniques in axial spondyloarthritis
• Treatment-response factors related to spondyloarthritis
• Current and upcoming treatment related to spondyloarthritis
• Next therapeutic target in spondyloarthritis
The Topic Editors declare no competing interests with regard to the Research Topic subject.
Keywords: Axial spondyloarthritis, innate immunity, precision medicine, imaging, biologics
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