Introduction to Sports Injuries by- Dr. Anjali Rai
Update pathogenesis of spondyloarthritis
1. Update Pathogenesis of
Spondyloarthritis
James Cheng-Chung WEI, MD, PhD
Chief, Division of Allergy, Immunology and Rheumatology
Director, Chinese Medicine Clinical Trial Center
Associate Professor, Chung Shan Medical University
9. The Gut in SpA
Ileocolonoscopy and biopsy found
subclinical gut inflammation in about 50%
of patients with SpA
Symptomatic inflammatory bowel disease
(IBD) in 6.5% of SpA
Sacroiliitis and spondylitis occurs in 1 to
26% of patients with IBD
SpA and IBD: share similar gene(1q32, STAT3,
IL-12B, IL-23R), TH17, and innate immunity.
10. Gut Microbials in AS
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An increased Klebsiella pneumonia in the fecal
cultures and anti-KP antibodies were associated
with degree of gut inflammation in AS
Chalmydia, Shigella, Salmonella, Yersinia, and
Campylobacter species are arthritogenic in ReA
Molecular mimicry between K.p. and self Crossreactive Antigens HLA-B27 & collagen
TLR and innate immunity play a role
Rashid T, Ebringer A. Discov Med. 2011 Sep;12(64):187-94
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Enthesis is a special organ
with fibrocartilage
Mechanical stress may
expose self Ag like Versican
and Aggrecan
17. Systemic IL-23 Expression in vivo Induces Highly Specific
Entheseal Inflammation
Entheseal inflammation at day 6 after administration of 3 μg IL23mc (bottom row) as compared to control treatment with human
α1 anti-trypsin minicircle (hAATmc, top row) in B10.RIII mice.
* Entheseal tendon-bone interface.
Adapted from: Sherlock JP et al. Nat Med 2012;18:1069-76 (with permission)
Histology of periosteal disease and
osteoblast expansion at day 18 after
treatment in B10.RIII mice.
20. Gut, Enthesis, HLA-B27 & IL-23 in SpA
Zhu et al Nat Med 18:1077-1086, 2012
Hu and O’Connell Nat Med 18:1009-1010,2012
Sherlock et al Nat Med 18:1069-1076, 2012
22. Take home message
Enthesitis and new bone formation are major
pathology of SpA.
Genetic factors are highly important in AS,
esp. HLA-B27, ERAP-1, IL23R.
Environmental factors, esp. gut microbials,
mechanical stress and smoking play a role.
TNFα and IL-17/22/23 are major cytokines
mediating SpA.
This cartoon shows you the difference..
For RA, the pathology is synovitis and marginal erosion mediated by TNF and osteoclase
For SpA, the pathology stats from enthesitis, mediated by not only TNF, but also BMP/Wnt in later stage, causing new bone formation.
Enthesitis is the halmark of SpA, Actually, enthesis is a special organ
The insertion site is usually over stressed by trauma
This is an importen paper last year in Nature Medicine about The entheseal stress hypothesis shown that Systemic
After injection of IL23, at day 6, you can see severe inflammation in the enthesis, and then osteoblast expansion at day 18.
So, my summary about organ specific are
This is a very nice summary figure about pathogenesis of SpA.
In B27+ subjects, the unfodled protein response initiated by gut bicrobiome and biomechanical stress, casusing transcription of inflam cytokines, esp IL23.
IL-23 activate TH17 rxn in the enthesis and then cause inflam, and finally osteoproliferation
In summary, I made this cartoon for my own hypothesus.
SpA need a genetic background, such as..
After trigger by environmental factors, such as..
The immune dysregulation attack enthesis through Th17 and Th1 rxn
With different genetic and Environmental factors, pts may have different phenotype, such as SpA or IBD.