Session Information
Session Type: Poster Session A
Session Time: 10:30AM-12:30PM
Background/Purpose: Both peripheral and axial spondyloarthropathy (SpA), psoriasis and inflammatory bowel disease are strongly linked to IL-23 pathway immunogenetics and immunology. Unexpectedly, IL-23 inhibition lacked efficacy in axial disease, namely Ankylosing Spondylitis (AS). Myeloid cells, which are substantial producers of IL-23, are rich in the red spinal marrow so we hypothesised considerable differences may exist between axial and peripheral sites, where haematopoiesis is less active. Therefore, we performed comparative immune studies of spinal, hip, and knee enthesis peri-entheseal bone (PEB) for IL-23 induction following stimulation.
Methods: Spinous process (n=5), hip capsule (n=4), and knee (n=4) PEB collected during orthopaedic surgery was mechanically digested to extract entheseal immune cells. Cell subsets were phenotyped by flow cytometry and stimulated with LPS and zymosan to assess IL-23-producing capacity. Quantification of cytokine production was achieved by ELISA and LEGENDplex assays.
Results: Despite similar cell populations present across each site, myeloid cells including monocytes and neutrophils were numerically more abundant per gram of tissue in the red marrow of spine and hip PEB but scarce in peripheral yellow marrow PEB, in keeping with the fact the spine and hip are haematopoietically active whereas the knee in adults is not. Following stimulation, spine and hip PEB produced 25-70 fold more IL-23 than knee PEB per gram of tissue (spine = 659.5 pg/g, hip = 1382.1 pg/g, knee = 24.8 pg/g; Figure 1).
Conclusion: his comparative immunology study of adult human entheses demonstrates axial PEB, the key target of AS pathology, produces significantly more IL-23 than knee PEB. The findings from our ex vivo stimulation studies raise the possibility that high-dosing regimens of IL-23 blockers may be needed to treat Ankylosing Spondylitis.
To cite this abstract in AMA style:
Harland M, David P, Wong C, Weddell J, Rao A, Khan A, Timothy J, Loughenbury P, Dunsmuir R, Borse V, MacEachern C, Van der Heuvel A, Chen W, Macleod T, McGonagle D. Comparative Immunology of Entheseal Anchorage Sites Between Spine, Hip and Knee Demonstrates up to 70-fold Greater IL-23 Induction from Axial Enthesis Bone: A New Angle on the Failure of IL-23 Blockade in Ankylosing Spondylitis [abstract]. Arthritis Rheumatol. 2024; 76 (suppl 9). https://acrabstracts.org/abstract/comparative-immunology-of-entheseal-anchorage-sites-between-spine-hip-and-knee-demonstrates-up-to-70-fold-greater-il-23-induction-from-axial-enthesis-bone-a-new-angle-on-the-failure-of-il-23-blockad/. Accessed .« Back to ACR Convergence 2024
ACR Meeting Abstracts - https://acrabstracts.org/abstract/comparative-immunology-of-entheseal-anchorage-sites-between-spine-hip-and-knee-demonstrates-up-to-70-fold-greater-il-23-induction-from-axial-enthesis-bone-a-new-angle-on-the-failure-of-il-23-blockad/