Tom Macleod, Charles Bridgewood, Dennis McGonagle, The Lancet Rheumatology Volume 5, Issue 1, January 2023, Pages e47-e57

Neutrophilic inflammation is a pervasive characteristic common to spondyloarthropathies and related disorders. This inflammation manifests as Munro’s microabscesses of the skin and osteoarticular neutrophilic inflammation in patients with psoriatic arthritis, intestinal crypt abscesses in patients with inflammatory bowel disease, ocular hypopyon in anterior uveitis, and neutrophilic macroscopic and microscopic inflammation in patients with Behçet’s disease. Strong MHC class I associations are seen in these diseases, which represent so-called MHC-I-opathies, and these associations indicate an involvement of CD8 T-cell immunopathology that is not yet well understood. In this Personal View, we highlight emerging data suggesting that the T-cell-neutrophil axis involves both a T-cell-mediated and interleukin (IL)-17-mediated (type 17) recruitment and activation of neutrophils, and also a sequestration of activated neutrophils at disease sites that might directly amplify type 17 T-cell responses. This amplification likely involves neutrophilic production of IL-23 and proteases as well as other feedback mechanisms that could be regulated by local microbiota, pathogens, or tissue damage. This crosstalk between innate and adaptive immunity offers a novel explanation for how bacterial and fungal microbes at barrier sites could innately control type 17 T-cell development, with the aim of restoring tissue homoeostasis, and could potentially explain features of clinical disease and treatment response, such as the fast-onset action of the IL-23 pathway blockade in certain patients. This axis could be crucial to understanding non-response to IL-23 inhibitors among patients with ankylosing spondylitis, as the axial skeleton is a site rich in neutrophils and a site of haematopoiesis with myelopoiesis in adults.

Role of neutrophil interleukin-23 in spondyloarthropathy spectrum disorders – ScienceDirect

Role of neutrophil interleukin-23 in spondyloarthropathy spectrum disorders – The Lancet Rheumatology

Chie Kurihara, Toshihide Ohmori, Kenichi Inaba, Shunsuke Komoto, Kengo Tomita, Ryota Hokari Gastroenterology 2020 158 (6) Suppl.S-1046

Background: Granulocyte and monocyte adsorptive apheresis (GMA) is non-pharmacological therapy which selective depletion of activated granulocytes and monocytes/macrophages from peripheral blood, and it is used as induction therapy for IBD. However, its therapeutic mechanism has not been well characterized. Recently, it has been reported that Th17 releases chemokines which attract neutrophils, and some neutrophils produce IL17. We investigated that changes in mRNA expression levels of inflammation associated molecules such as cytokines, chemokines in colonic mucosa of ulcerative colitis (UC) patients before and after GMA treatment in order to obtain further understanding of GMA therapeutic mechanisms. Methods: Thirty-two active UC patients (Mayo score ≥ 5 and Mayo endoscopic score ≥ 2) and 10 non-IBD control subjects were enrolled in this study. All UC patients received 10 times of GMA, and colonoscopies were applied before the first GMA and after the last GMA. Control subjects underwent colonoscopies for screening of colon cancer. Assessment of GMA therapeutic efficacy was determined based on Mayo score. Inflammation-related molecules mRNA expressions were determined by quantitative RT-PCR using biopsy specimen of colonic mucosa. Results: GMA treatment efficacy is 11 patients (34.4%) achieved clinical remission, 17 patients (53.1%) were response and 4 patients (12.5%) were non-response. Baseline characteristics such as sex, location of disease, CRP, WBC and Mayo score were not significantly different according to GMA efficacy. In the remission group, mRNA levels in mucosal tissue of IL1β, IL6, IL17, IL23 and GM-CSF which are Th17-asociated cytokines significantly decreased after the last GMA compared to the baseline levels(P<0,05) in contrast, expression of these mRNA tended to increase following GMA treatment in the non-response group. On the other hand, IL12 and IFN- γ which are associated with Th1 did not significantly decrease in the remission group. mRNA levels of leukocyte trafficking associated molecules such as MAdCAM-1, ICAM-1, integrinβ7, IL8 and MIP-1β significantly decreased following GMA treatment in the remission group(P <0.05), whereas only IL8 mRNA expression in the non-response group tended to increase. IL1 β, IL6, GM-CSF which are Th17-asociated cytokines and IL8 mRNA expressions in post-GMA treatment were significantly higher in the non-response group compared to the remission group or control group(P <0.05). Conclusion: In UC patients who achieved clinical remission by GMA, Th17- associated cytokines and leukocyte trafficking associated molecules but not Th1-asociated cytokines decreased significantly. Furthermore, Th17-asociated cytokines increased in the non-responders. These results reaffirm the involvement of neutrophil in the pathophysiology of UC and could be helpful for characterizing of GMA therapeutic mechanism.

https://www.gastrojournal.org/article/S0016-5085(20)33300-X/pdf

Yuji Naito ¹, Tomohisa Takagi, Toshikazu Yoshikawa

J Gastroenterol  2007 Oct;42(10):787-98. doi: 10.1007/s00535-007-2096-y. Epub 2007 Oct 15.

Neutrophil accumulation within epithelial crypts and in the intestinal mucosa directly correlates with clinical disease activity and epithelial injury in inflammatory bowel disease (IBD). Current advances have defined the mechanisms by which neutrophils are activated or migrate across endothelial and mucosal epithelial cells. A better understanding of this process will likely provide new insights into novel treatment strategies for IBD. Especially, activated neutrophils produce reactive oxygen and nitrogen species and myeloperoxidase within intestinal mucosa, which induce oxidative stress. Posttranslational modification of proteins generated by these reactive species serves as a „molecular fingerprint“ of protein modification by lipid peroxidation-, nitric oxide-, and myeloperoxidase-derived oxidants. Measurement of these modified proteins may serve both as a quantitative index of oxidative stress and an important new biological marker of clinical relevance to IBD. We have succeeded in the clinical development of a novel granulocyte adsorptive apheresis therapy for IBD. In this review, we discuss current advances in defining the role of neutrophil-dependent oxidative stress in IBD.

https://pubmed.ncbi.nlm.nih.gov/17940831/