The role of IL-17A in axial spondyloarthritis and psoriatic arthritis: recent advances and controversies

The gut microbiota in spondyloarthritis: an update

PURPOSE OF REVIEW

This review provides an updated overview of the gut microbiota's involvement in spondyloarthritis (SpA) from a clinical perspective. It explores mechanisms by which the gut microbiota may influence SpA pathogenesis and considers the therapeutic implications of targeting the microbiome in SpA treatment.

RECENT FINDINGS

The pathogenesis of SpA is multifactorial, involving genetic predisposition, external factors and dysregulation of the immune system. Recent studies have identified alterations in the gut microbiome of patients with SpA, including changes in microbial diversity and specific taxa linked to disease activity. HLA-B27 status seems to influence gut microbiota composition, potentially impacting disease progression. In HLA-B27 transgenic rats, the association between gut microbiota and SpA development has been confirmed, supporting findings from human studies. A compromised gut barrier, influenced by proteins like zonulin, may allow microbial antigens to translocate, triggering immune responses associated with SpA.

SUMMARY

These findings highlight the potential for microbiota-modulating therapies, such as probiotics, prebiotics, diet and exercise, in managing SpA. However, methodological variability in human studies exposes the need for more rigorous research to better understand these associations. This may offer the opportunity to refine treatment strategies, offering a personalized approach to managing the disease.

FGF7 as an essential mediator for the onset of ankylosing enthesitis related to psoriatic dermatitis

IL-17A plays an important role in the pathology of psoriasis and psoriatic arthritis (PsA). However, the pathogenic association between the skin and joint manifestations in PsA is not completely understood. In this study, we initially observed that IL-17A and FGF7 induced endochondral ossification in the mouse entheseal histoculture. Importantly, the responses of endochondral ossification by IL-17A stimulation were strongly inhibited by the treatment of a blocking antibody to FGF receptor 2IIIb, which is the receptor of FGF7, suggesting that FGF7 acts as a downstream factor of IL-17A in the endochondral ossification in the culture. Next, using the animal PsA model, the administration of an anti-FGF receptor 2IIIb antibody resulted in significant suppression of ankylosing enthesitis but not dermatitis. Collectively, our findings indicate that augmented IL-17A in PsA dermatitis induces the elevation of FGF7 levels in joint enthesis and results in a non-redundant role of FGF7 signaling in the development of ankylosing enthesitis in PsA.

Interleukin 17-producing C-C motif chemokine receptor 6 + conventional CD4+ T cells are arthritogenic in an animal model of spondyloarthritis

OBJECTIVE

Spondyloarthritis (SpA) is a group of chronic inflammatory disorders associated with the human leukocyte antigen (HLA) class I allele HLA-B27. Transgenic rats expressing HLA-B27 and human β2-microglobulin (B27 rats) develop clinical manifestations resembling SpA called rat SpA. IL-17 and TNF are key proinflammatory cytokines implicated in both human and rat SpA. We aimed to determine which T cell subset(s) produce IL-17 and TNF during rat SpA, characterize their tissue distribution and tested their pathogenicity in vivo.

METHODS

Cytokine production by T cell subsets was evaluated in target tissues and lymphoid organs during rat SpA. Pathogenicity of purified IL-17+ cells was assessed in vivo by cell transfer. Blood samples were used to translate B27 rats findings to SpA patients.

RESULTS

Conventional CD4+ T cells (Foxp3-; Tconv) and γδ T cells were the main producers of both IL-17 and TNF in B27 rats. IL-17-producing Tconv and γδ T cells were expanded in the colon of premorbid 3-weeks-old B27 rats. C-C motif chemokine receptor 6 (CCR6) allowed the isolation of IL-17+ Tconv (Th17) in rat. Transfer of B27 rat IL-17-producing CCR6+ Tconv but not of γδ T cells into disease-free nude B27 rats induced arthritis, directly demonstrating for the first time the arthritogenic potential of Th17 cells in SpA. Finally, a CCR6+ IL-17+ Tconv expansion enriched for IL-17F production was evidenced in SpA patients.

CONCLUSION

Our study demonstrates that IL-17+TNF+CCR6+ Th17 cells and IL-17+ γδ T cells are expanded preceding SpA onset in B27 rats and that only IL-17+TNF+CCR6+ Th17 cells can trigger arthritis.

Australasian hidradenitis suppurativa management guidelines

Hidradenitis Suppurativa is a burdensome inflammatory skin disease with significant quality of life impact. These management guidelines were developed to direct appropriate clinical management in the Australasian context. A systematic review was used for the basis of the consensus guidelines. Thirteen clinical experts were involved in a modified Delphi consensus process to develop the guidelines and treatment algorithms. Overall management strategies include appropriate severity assessment of disease and comorbidities, multimodal therapy with systemic and local treatments, and evidence-based progression along the therapeutic ladder in the event of inadequate response. Sequential monotherapy with antibiotics and/or single agent therapy is discouraged and aggressive treatment of moderate to severe disease to capture the window of opportunity is highly emphasised. Specific considerations in the setting of disease comorbidities, pregnancy and breastfeeding are also addressed. Overall, the complex nature of HS requires a complex and multimodal therapeutic response with medical, physical and surgical therapies to achieve best patient outcomes.

Secukinumab in refractory non-infectious anterior uveitis

Background

Secukinumab is a monoclonal antibody that selectively neutralizes interleukin-17A and has shown efficacy in the treatment of psoriatic arthritis, psoriasis, and axial spondyloarthritis. Its use in non-anterior non-infectious uveitis is controversial, with evidence generally not supporting its effectiveness in these conditions. However, the role of secukinumab in anterior non-infectious uveitis remains unclear.

Methods

Case series. Five patients with biological therapy-refractory non-infectious anterior uveitis who were treated with secukinumab were included.

Results

All 5 patients experienced a uveitis flare-up during treatment, and secukinumab failed to induce long-term remission in 2 of these patients, who also had uncontrolled systemic disease.

Conclusion

Secukinumab failed to prevent uveitis flare-up in these patients with biological therapy-refractory disease. Further studies are necessary to determine the potential role of secukinumab in the treatment of anterior uveitis.

The effect of ixekizumab treatment on MRI sacroiliac joint structural lesions in patients with radiographic axial spondyloarthritis: post-hoc analysis of a 52-week, randomised, placebo-controlled trial with an active reference arm

BACKGROUND

The effect of biological disease-modifying antirheumatic drugs (DMARDs) on sacroiliac joint lesions over 52 weeks in biological DMARD-naive patients with radiographic axial spondyloarthritis is unknown. This post-hoc analysis evaluated the effect of ixekizumab and adalimumab versus placebo on structural lesions in sacroiliac joints assessed by MRI in patients naive to biological DMARDs with radiographic axial spondyloarthritis from the COAST-V study.

METHODS

COAST-V was a phase 3, multicentre, randomised, double-blind, placebo-controlled trial with an active reference arm done over 52 weeks at 84 sites in 12 countries. Eligible patients were adults (aged ≥18 years) naive to biological DMARDs with active radiographic axial spondyloarthritis, radiographic evidence of sacroiliitis, and an inadequate response or intolerance to non-steroidal anti-inflammatory drugs. Patients were randomly assigned (1:1:1:1) to 80 mg ixekizumab every 2 weeks (Q2W) or every 4 weeks (Q4W), 40 mg adalimumab Q2W, or placebo. At week 16, patients receiving placebo or adalimumab were randomly assigned (1:1) again to ixekizumab Q2W or ixekizumab Q4W. Post-hoc analyses of patients with MRI available at baseline, 16 weeks, and 52 weeks are reported. MRIs were scored using the Spondyloarthritis Research Consortium of Canada sacroiliac joint structural scores for erosion, backfill, fat lesions, and ankylosis. ANCOVA was used for treatment comparisons in observed cases adjusting for baseline values, bone marrow oedema, and stratification factors. Subgroup analyses by sex, HLA-B27, and baseline bone marrow oedema were done.

FINDINGS

Between June 20, 2016, and Aug 22, 2017, 341 patients were enrolled in the COAST-V study. MRI scans were available for 325 (95%) of 341 patients at baseline and week 16, and for 301 (88%) patients at week 52. 264 (81%) of 325 patients were male and 61 (19%) were female, and the mean age was 41·5 years (SD 11·6). At week 16, erosion significantly decreased versus placebo in the ixekizumab Q2W group (least squares mean -0·91 [SE 0·19] vs 0·10 [0·18]; p<0·0001) and the ixekizumab Q4W group (-0·57 [SE 0·19]; p=0·0086]); the effect of adalimumab was similar. Backfill significantly increased from baseline to week 16 in ixekizumab Q2W versus placebo (0·52 [0·12] vs 0·04 [0·12]; p=0·0042). At week 16, decreases in erosion differed significantly between the placebo group and ixekizumab Q2W or Q4W groups, and differences were seen by sex, HLA-B27 status, and baseline bone marrow oedema score. At week 52, at both ixekizumab doses, further changes were observed in erosion and backfill, which were greatest with continuous ixekizumab Q2W (mean erosion -1·50 [SD 2·70], mean backfill 0·76 [SD 2·09]). A decrease in erosion was also noted in patients switching from adalimumab to ixekizumab at week 16. COAST-V was registered with ClinicalTrials.gov (NCT02696785).

INTERPRETATION

A decrease in erosion and increase in backfill were observed at week 16 with further reductions in erosion and increases in backfill occurring at week 52 in patients receiving ixekizumab. Ixekizumab, like adalimumab, modifies structural lesions that is consistent with a rapid tissue response in patients with radiographic axial spondyloarthritis. However, the effect on the development of ankylosis in sacroiliac joints or the spine requires further analysis.

FUNDING

Eli Lilly.

Causal Relationship Between Autoimmune Rheumatic Diseases and Iridocyclitis: A Bidirectional Two-Sample Mendelian Randomization Study

PURPOSE

This study aims to explore the relationship between autoimmune rheumatic diseases (ARDs) and the risk of iridocyclitis (IC) using Mendelian randomization (MR) analysis.

METHODS

Data of ankylosing spondylitis (AS), systemic lupus erythematosus (SLE), juvenile idiopathic arthritis (JIA), Behcet's disease (BD), and iridocyclitis were obtained from genome-wide association studies with large sample sizes. The instrumental variable utilized in this study for each exposure was the single nucleotide polymorphism. The inverse-variance weighted (IVW) method, which included random effects, was used to analyze causal effects. In addition, sensitivity analyses were conducted using the weighted median and MR-Egger methods. The presence of pleiotropic effects was identified and addressed through MR pleiotropic effects residual and outlier tests, as well as MR-Egger modeling.

RESULTS

We found a causal effect of AS (IVW, OR = 2.74 × 1029, 95% CI 6.39 × 107 - 1.18 × 1051, p = 0.008) on IC. Conversely, we also found a causal effect of IC on AS (IVW OR = 1.01, 95% CI 1.00 - 1.01, p < 0.001). Besides, sensitivity analysis showed no evidence of pleiotropy and heterogeneity. However, no causal relationship between SLE, JIA, BD, and IC was detected.

CONCLUSION

Bilateral causal relationships of IC and AS were identified, which could offer evidence for clinical use and lay the groundwork for detecting potential mechanism behind them.

Emerging biochemical, microbial and immunological evidence in the search for why HLA-B∗27 confers risk for spondyloarthritis

The strong association of the human leukocyte antigen B∗27 alleles (HLA-B∗27) with spondyloarthritis and related rheumatic conditions has long fascinated researchers, yet the precise mechanisms underlying its pathogenicity remain elusive. Here, we review how interplay between the microbiome, the immune system, and the enigmatic HLA-B∗27 could trigger spondyloarthritis, with a focus on whether HLA-B∗27 presents an arthritogenic peptide. We propose mechanisms by which the unique biochemical characteristics of the HLA-B∗27 protein structure, particularly its peptide binding groove, could dictate its propensity to induce pathological T cell responses. We further provide new insights into how TRBV9+ CD8+ T cells are implicated in the disease process, as well as how the immunometabolism of T cells modulates tissue-specific inflammatory responses in spondyloarthritis. Finally, we present testable models and suggest approaches to this problem in future studies given recent advances in computational biology, chemical biology, structural biology, and small-molecule therapeutics.

Is middle East pain syndrome (MEPS) a variant of fibromyalgia syndrome or a distinct disease?

BACKGROUND

Fibromyalgia Syndrome (FMS) is a chronic disabling musculoskeletal condition of unknown aetiology characterized by generalized musculoskeletal pain, extreme fatigue, mood disturbance, impaired cognition, and lack of refreshing sleep. Middle East pain syndrome (MEPS) is a newly described pollution-induced syndrome of hyperparathyroidism and fibromyalgia mimicking rheumatoid arthritis, characterized by the radiological presence of spur-like excrescences in terminal phalanges. This study aimed to explore the inflammatory nature of Middle East pain and Fibromyalgia syndromes.

METHODS

Eighty primary fibromyalgia patients were included in this study. They were divided into two groups, group [1] 1 of 40 FMS patients with low vitamin D levels and secondary hyperparathyroidism, which were diagnosed as MEPS, and group [2] of 40 primary FMS patients. They were subjected to full medical history taking, clinical examination and laboratory assessment including serum IL-17 by enzyme-linked immunosorbent assay technique, as well as assessment of Madrid Sonographic Enthesitis Index (MASEI) using musculoskeletal ultrasound and nailfold capillaroscopic pattern assessment. Plain X-ray films for hands were done on all patients.

RESULTS

There was a statistically significant elevation of serum IL17 in the MEPS group (median = 58.3 ng/L) compared to the FMS group (median = 45.7 ng/L) as the p-value is < 0.05. Capillaroscopic examination revealed a statistically significant difference between MEPS and FMS groups regarding angiogenesis as the p-value is < 0.05. The ultrasonographic examination also showed a statistically significant difference between MEPS and FMS groups as regards MASEI score as the p-value is < 0.05. Hands X-rays evidenced the exclusive existence of tuft spur-like excrescences in MEPS patients only.

CONCLUSION

Elevated IL-17 levels, non-scleroderma pattern capillaroscopic and enthesopathy findings in both MEPS and FMS patients are strongly supportive that inflammatory mechanisms participate in the pathogenesis of both diseases. The significant increase of these findings in MEPS than FMS patients as well as the presence of hand tufts spur-like excrescences, confirm that the newly discovered MEPS is a different disease although it involves fibromyalgia symptoms and signs.

Extracellular Vesicles Derived from Ligament Tissue Transport Interleukin-17A to Mediate Ligament-To-Bone Crosstalk in Ankylosing Spondylitis

Pathological new bone formation is a critical feature of the progression of ankylosing spondylitis (AS), and spine ankylosis is a distinctive feature of this condition. Ligaments are the primary regions of pathological new bone formation in AS. Here, it is demonstrated that ligament tissue-derived extracellular vesicles (EVs) and their interleukin-17A (IL-17A) cargo mediate the communication between the tissue and other cells. The investigation revealed that IL-17A in EVs can activate the JAK-STAT3 pathway, thereby stimulating the expression of MMP14 in AS ligament. Overexpression of MMP14 can lead to changes in the cytoskeleton and mechanical signaling of mesenchymal stem cells and other cells. These alterations in cellular cytoskeleton and mechanical signaling at ligament sites in patients with AS or in stem cells treated with EVs can result in pathological new bone formation. Finally, inhibiting IL-17A activity and EV endocytosis effectively controlled inflammation and pathological new bone formation. Overall, these data suggest that ligament-derived EVs and the enclosed IL-17A have a potential role in driving pathological new bone formation in AS, and targeting EVs may therefore emerge as a novel approach to delaying ectopic ossification in AS.

A review and recommendations on the management of psoriatic arthritis in Australia 2024

Psoriatic arthritis (PsA) is a progressive, systemic inflammatory disease. It can lead to serious joint damage and disability, increased cardiovascular risk and reduced quality of life. Six experts met to develop the recommendations for the management of PsA in Australia. The final recommendations are approved by all panel members. Management and treatment recommendations have been made under six subheadings: Recommendations for non-steroidal anti-inflammatory drugs and glucocorticoids; Disease-modifying treatment; Screening and monitoring; Family planning; Symptom treatment and extra-articular manifestations; Comorbidities and lifestyle considerations. Our recommendations for the management of PsA in Australia draw heavily on the established global guidelines. These recommendations aim to assist clinicians to make informed, patient-centric choices when delivering treatment to people with PsA.

Treatment controversies in spondyloarthritis and psoriatic arthritis: focus on biologics and targeted therapies

INTRODUCTION

There are several treatment controversies that have emerged in spondyloarthritis and psoriatic arthritis. These are related to the nature of the conditions as well as to the use of medications.

AREAS COVERED

This review, which included a search of PubMed database as well as the references within the articles provides an overview of the nature of spondyloarthritis, controversy over the inclusion of psoriatic arthritis (PsA) as a peripheral spondyloarthritis, and a summary of current treatments for both PsA and axial spondyloarthritis (axSpA), with special emphasis on targeted therapy. The review highlights the differences in response to certain medications, particularly biologic therapy and summarizes the randomized controlled trials in psoriatic arthritis and axial spondyloarthritis providing data about the responses in table format.

EXPERT OPINION

There is a need for better outcome measures in axSpA. Currently, the measures are subjective. Imaging may be more appropriate but there is a need for research into the reliability and responsiveness of imaging techniques. In PsA, there may also be better response measures and research into the reliability and responsiveness of available measures is underway. There is also a need for novel therapies as well as biomarkers for response in both diseases.

Preliminary Investigation and Therapeutic Efficacy Determination of a Novel Anti-IL-17A Antibody, Indikizumab

Purpose

The study aimed to develop and characterize Indikizumab, a novel humanized anti-IL-17A monoclonal antibody (mAb), for potential therapeutic use in inflammatory indications such as psoriasis, psoriatic arthritis, rheumatoid arthritis, and ankylosing spondylitis.

Methods

The research involved the purification of IL-17 isoforms, epitope mapping, affinity ranking, and comparative binding assessment of anti-IL-17 antibodies. The study also included cell-based neutralization assays and in vivo studies using mouse models to evaluate the efficacy of Indikizumab.

Results

Indikizumab demonstrated a high binding affinity (KD=27.2 pM) and specificity for IL-17A, with comparable potency to Secukinumab. In cell-based neutralization assays, Indikizumab effectively neutralized the effects of IL-17A and demonstrated a statistically significant reduction in plasma KC (Keratinocyte) levels in a mouse model. In imiquimod-induced psoriasis mouse model, Indikizumab showed potential in reducing the psoriasis index.

Conclusion

Indikizumab represents a promising therapeutic option for inflammatory indications with its high binding affinity, specificity for IL-17A, and effectiveness in neutralizing IL-17A effects in vivo.

Early psoriatic arthritis: clinical and therapeutic challenges

INTRODUCTION

Psoriatic arthritis (PsA) is a chronic immunoinflammatory disease of the enthesis and adjacent synovium, skin, and nail, which early diagnosis may be crucial for starting a prompt therapeutic intervention. Theoretically, early treatment offers the advantage of acting on the reduction of the articular damage progression since initial phases of the disease.

AREAS COVERED

This review explores the challenges of clinical-diagnostic aspects and the underlying pathophysiology of early PsA phases, as well as the evidence evaluating the impact of early intervention on disease outcomes.

EXPERT OPINION

Main instruments for early PsA diagnosis include recognizing synovial-entheseal inflammatory signs at onset, improving screening PsA high-risk subjects, and increasing disease knowledge of physicians and patients with psoriasis or familial history. PsA continues to significantly impact on the Quality of Life of patients affected by the disease, making necessary to deeply study clinical manifestations, risk factors, and underlying immunoinflammatory mechanisms, as well as to identify biomarkers for early identification. Additionally, it remains a need to increase more evidence on understanding how early treatment of PsA and of psoriasis might influence the course of the disease.

IL-17 inhibitors in axial spondyloarthritis. An overview

INTRODUCTION

The therapeutic armamentarium for spondyloarthritis has expanded considerably in recent years, and there is growing evidence to support the increasing use of IL-17 inhibitors (IL-17i) in axial spondyloarthritis (axSpA).

AREAS COVERED

This literature review provides an update on the role of IL-17 in the pathogenesis of axSpA, efficacy and safety from clinical trials and real-life studies on the use of IL17i in axSpA. We also review the impact of extra-musculoskeletal manifestations on the decision to treat with IL17i and the efficacy of IL17i on structural progression.

EXPERT OPINION

There are still some unanswered questions concerning the use of IL-17i in axSpA in clinical practice such as their respective place in the management of axSpA compared to TNFα inhibitors (TNFi). Their main differences rely on their specific efficacy in extra-articular manifestations such as psoriasis, uveitis, and inflammatory bowel diseases leading to the choice of the best treatment in a given patient. Regarding their real impact on structural progression, the rate of progression under IL-17i appears to be low and presumably similar to TNFi. One final question is the advantage of blocking the two IL-17 isoforms A and F compared to the single inhibition of IL-17A.

Male Fertility in Spondyloarthritis: from Clinical Issues to Cytokines Milieu. A Narrative Review

PURPOSEOF REVIEW

Male fertility is an emergent issue that should be considered in clinical practice, when dealing with chronic inflammatory diseases in young men. As it is known, the chronic inflammation is the main pathophysiologic mechanism in some rheumatological conditions such as spondyloarthritis (SpA), Ankylosing Spondylitis (AS) and Psoriatic Arthritis (PsA). Therefore, it is paramount to be aware if these diseases could impair male fertility, both due to the inflammation or to the treatments needed: we reviewed the literature on the most relevant and recent evidence on male fertility in patients affected by SpA, AS and PsA.

RECENT FINDINGS

Rheumatological inflammatory diseases (included SpA, AS and PsA) could impair the family planning in man life, especially when diagnosed at young age. Moreover, focusing on sperm quality, it seems that a link between sperm quality impairment and a higher disease activity exist. Focusing on therapies, Tumor Necrosis Factor inhibitors showed a safety profile on human male fertility in clinical studies. Recently, a prospective study and two double-blind placebo-controlled trials assessed the impact of methotrexate and Filgotinib on semen parameters, respectively, showing a safety profile of these drugs on human semen quality. However, there are no clinical data on the impact of Interleukin (IL)17 inhibitors(i), IL12-23i and IL23i. Concerning male fertility in SpA, AS and PsA, an unmet clinical need is still present and new studies are needed to understand the association between these diseases and male fertility, and the implication of the therapies used for these diseases. This narrative review provides an overview of the available data on male fertility in patients affected by SpA, AS and PsA.

Elevated serum IL-36γ levels in patients with ankylosing spondylitis and its association with disease activity

Ankylosing spondylitis (AS) is a chronic autoimmune disease. The purpose of this study was to investigate the levels of serum IL-36γ in AS patients and their association with AS. The study enrolled 131 subjects, including 45 with active AS, 46 with inactive AS, and 40 healthy controls (HCs). The basic clinical information of each participant was obtained through physical examination and relevant clinical medical records. Serum IL-36γ levels were detected through an enzyme-linked immunosorbent assay. Serum IL-36γ levels in the active AS group were significantly higher than those in the HC group (94.72 vs. 65.76 pg/mL, P = 0.0087). The serum IL-36γ concentration in the inactive AS group was increased as compared to that in the HC group (100.90 vs. 65.76 pg/mL, P = 0.0138). Correlation analysis indicated that serum IL-36γ was positively correlated with glutamyl transferase in the active AS group (P = 0.0172), while serum IL-36γ was positively correlated with uric acid in the inactive AS group (P = 0.0151). The area under the curve (AUC) for IL-36γ was 0.6824 (P = 0.0009), and the AUC for IL-36γ combined with the erythrocyte sedimentation rate and C-reactive protein levels was 0.8102 (P < 0.0001), according to receiver operating characteristic curve analysis. This study found that serum IL-36γ levels were elevated in AS patients and correlated with disease activity. Our results suggest that IL-36γ may be involved in the progression of AS disease and is a potential biomarker for AS.

A Randomized, Double-Blind, Parallel-Group Phase I Study Comparing the Pharmacokinetics, Safety, and Immunogenicity of CMAB015, a Candidate Secukinumab Biosimilar, with Its Reference Product Cosentyx® in Healthy Chinese Male Subjects

Purpose

Secukinumab, a monoclonal antibody targeting interleukin (IL)-17A, is approved for the treatment of psoriasis, psoriatic arthritis, ankylosing spondylitis, non-radiographic axial spondyloarthritis, enthesitis-related arthritis, and hidradenitis suppurativa. This study compared the pharmacokinetics (PK), safety, and immunogenicity of CMAB015, a candidate secukinumab biosimilar, with the reference product secukinumab (Cosentyx®) in healthy Chinese male subjects.

Patients and methods

This double-blind, parallel-group study randomized healthy Chinese male subjects (N=130) to receive either a single dose of 150 mg CMAB015 or secukinumab subcutaneously. Primary study endpoints were PK parameters such as the maximum concentration (Cmax) and area under the curve from zero to infinity (AUC0-inf), while safety and immunogenicity were secondary endpoints.

Results

The 90% confidence intervals (CIs) of the geometric mean ratios (GMRs) of Cmax and AUC0-inf for CMAB015 to secukinumab were all within the bioequivalence limits (80.00-125.00%). Other PK parameters were comparable between the groups. The safety profile of CMAB015 was similar to that of secukinumab, with no serious adverse events related to treatment. The incidence of TEAEs was slightly higher in the CMAB015 group, but these events were mild to moderate in severity and did not lead to any withdrawals from the study. Immunogenicity analysis revealed low rates of anti-drug antibody (ADA) positivity, with similar rates between CMAB015 and secukinumab.

Conclusion

This study demonstrated equivalent PK, comparable safety, and immunogenicity of CMAB015 to secukinumab in healthy Chinese male subjects. These findings support further clinical evaluation of CMAB015 as a secukinumab biosimilar.

Trial Registration

The trial was registered on Clinicaltrials.gov (Identifier No. NCT05734482) and Chinadrugtrials.org.cn (Identifier No. CTR20230105).

Targeting cytokines in psoriatic arthritis

Psoriatic arthritis (PsA) is part of the psoriatic disease spectrum and is characterized by a chronic inflammatory process that affects entheses, tendons and joints. Cytokines produced by immune and non-immune cells play a central role in the pathogenesis of PsA by orchestrating key aspects of the inflammatory response. Pro-inflammatory cytokines such as TNF, IL-23 and IL-17 have been shown to regulate the initiation and progression of PsA, ultimately leading to the destruction of the architecture of the local tissues such as soft tissue, cartilage and bone. The important role of cytokines in PsA has been underscored by the clinical success of antibodies that neutralize their function. In addition to biologic agents targeting individual pro-inflammatory cytokines, signaling inhibitors that block multiple cytokines simultaneously such as JAK inhibitors have been approved for PsA therapy. In this review, we will focus on our current understanding of the role of cytokines in the disease process of PsA and discuss potential new treatment options based on modulation of cytokine function.

Rare Case Report of Primary Active Pulmonary Tuberculosis During Ixekizumab Treatment for Plaque Psoriasis

Biologic agents have become a mainstay in the treatment of psoriasis, particularly in moderate to severe, refractory, and special types of the disease. Among these, ixekizumab is a humanized IgG4 monoclonal antibody targeting interleukin-17A, approved for the treatment of moderate to severe plaque psoriasis. Its adverse effects include infections such as nasopharyngitis, upper respiratory tract infections, and injection site reactions. While the incidence of tuberculosis (TB) associated with IL-17A antagonists is extremely low, this paper reports a case of active pulmonary tuberculosis occurring after ten doses of ixekizumab treatment for chronic plaque psoriasis. This highlights the importance for clinicians to remain vigilant regarding tuberculosis infection in patients undergoing therapy with this class of medications, emphasizing the need for enhanced screening and monitoring for tuberculosis during treatment.

Discovery and preclinical evaluation of KYS202004A, a novel bispecific fusion protein targeting TNF-α and IL-17A, in autoimmune disease models

The treatment of autoimmune and inflammatory diseases often requires targeting multiple pathogenic pathways. KYS202004A is a novel bispecific fusion protein designed to antagonize TNF-α and IL-17A, pivotal in the pathophysiology of autoimmune and inflammatory diseases. Our initial efforts focused on screening for optimal structure by analyzing expression levels, purity, and binding capabilities. The binding affinity of KYS202004A to TNF-α and IL-17A was evaluated using SPR. In vitro, we assessed the inhibitory capacity of KYS202004A on cytokine-induced CXCL1 expression in HT29 cells. In vivo, its efficacy was tested using a Collagen-Induced Arthritis (CIA) model in transgenic human-IL-17A mice and an imiquimod-induced psoriasis model in cynomolgus monkeys. KYS202004A demonstrated significant inhibition of IL-17A and TNF-α signaling pathways, outperforming the efficacy of monotherapeutic agents ixekizumab and etanercept in reducing CXCL1 expression in vitro and ameliorating disease markers in vivo. In the CIA model, KYS202004A significantly reduced clinical symptoms, joint destruction, and serum IL-6 concentrations. The psoriasis model revealed that KYS202004A, particularly at a 2  mg/kg dose, was as effective as the combination of ixekizumab and etanercept. This discovery represents a significant advancement in treating autoimmune and inflammatory diseases, offering a dual-targeted therapeutic approach with enhanced efficacy over current monotherapies.

Plasma proteins and psoriatic arthritis: a proteome-wide Mendelian randomization study

Background

Previous epidemiological studies have identified a correlation between serum protein levels and Psoriatic Arthritis (PsA). However, the precise nature of this relationship remains uncertain. Therefore, our objective was to assess whether circulating levels of 2,923 plasma proteins are associated with the risk of PsA, utilizing the Mendelian randomization (MR) approach.

Methods

Two-sample MR analysis was performed to assess the causal impact of proteins on PsA risk. Exposure data for plasma proteins were sourced from a genome-wide association study (GWAS) conducted within the UK Biobank Pharma Proteomics Project, which encompassed 2,923 unique plasma proteins. The outcome data for PsA were sourced from the FinnGen study, a large-scale genomics initiative, comprising 3,537 cases and 262,844 controls. Additionally, colocalization analysis, Phenome-wide MR analysis, and candidate drug prediction were employed to identify potential causal circulating proteins and novel drug targets.

Results

We thoroughly assessed the association between 1,837 plasma proteins and PsA risk, identifying seven proteins associated with PsA risk. An inverse association of Interleukin-10 (IL-10) with PsA risk was observed [odds ratio (OR)=0.45, 95% confidence interval (CI), 0.28 to 0.70, P FDR=0.072]. Additionally, Apolipoprotein F (APOF) has a positive effect on PsA risk (OR=2.08, 95% CI, 1.51 to 2.86, P FDR=0.005). Subsequently, we found strong evidence indicating that IL-10 and APOF were colocalized with PsA associations (PP.H4 = 0.834 for IL-10 and PP.H4 = 0.900 for APOF). Phenome-wide association analysis suggested that these two proteins may have dual effects on other clinical traits (P FDR<0.1).

Conclusion

This study identified 7 plasma proteins associated with PsA risk, particularly IL-10 and APOF, which offer new insights into its etiology. Further studies are needed to assess the utility and effectiveness of these candidate proteins.

Raftlin - a potential biomarker for axial spondyloarthritis and psoriatic arthritis: An observational study

Our aim is to evaluate serum Raftlin levels as a biomarker for diagnosing and monitoring disease activity in patients with axial spondyloarthritis (axSpA) and Psoriatic arthritis (PsA). This trial included 40 axSpA patients, 40 PsA patients, and 40 healthy participants as the control group. Disease activity was assessed with Ankylosing Spondylitis Disease Activity Score for axSpA patients and The Disease Activity Index for Psoriatic Arthritis for PsA patients. The Spondyloarthritis Research Consortium of Canada index, health assessment questionnaire-disability index, and numeric rating scale were used to evaluate the enthesitis severity, disability, and pain status of all patients. Serum Raftlin levels were determined using the ELISA method. The 3 groups had no statistical differences regarding gender, age, weight, height, BMI, educational status, and exercise habits. The axSpA group had higher Raftlin levels than the PsA and control groups, and Raftlin levels were statistically significant in predicting the likelihood of axSpA. We found no statistically significant differences between the PsA and control groups. We found no statistically significant difference in Raftlin levels in HLA-B27 positive versus HLA-B27 negative patients in both axSpA and PsA groups. Our results also did not detect any correlation of Raftlin levels with Ankylosing Spondylitis Disease Activity Score, C-reactive protein, erythrocyte sedimentation rate, health assessment questionnaire-disability index, numeric rating scale, and Spondyloarthritis Research Consortium of Canada index in axSpA patients. Receiver operating characteristic analysis determined that Raftlin level ≥ 6.31 ng/mL discriminates axSpA from normal individuals with 92.5% sensitivity, 59% specificity, and an area under the curve of 0.738. Our results demonstrate that although serum Raftlin levels are elevated in axSpA patients, Raftlin cannot be used as an alone diagnostic marker for axSpA. Furthermore, it was not found to be related to the monitoring of disease activity, the level of pain, disability, or severity of enthesitis. This study is prospectively registered at www.clinicaltrials.gov (ID: NCT05771389).

Identification and Clinical Correlation of Circulating MAIT, γδ T, ILC3, and Pre-Inflammatory Mesenchymal Cells in Patients with Rheumatoid Arthritis and Spondyloarthritis

Inflammatory rheumatic diseases (IRDs), such as rheumatoid arthritis (RA) and spondyloarthropathy (SpA), comprise a heterogeneous group of immune-mediated disorders, characterised by the presence of localised and/or systemic inflammation. The limited knowledge of the pathogenesis and the complex mechanisms involved in the induction and maintenance of inflammation in IRDs have impeded the development of reliable biomarkers and the discovery of new therapeutic targets. Although the involvement of heterogeneous cell populations in the pathogenesis of IRDs has been recognised, the characterisation of these cellular subsets in the peripheral blood of patients has not been studied yet. Mass cytometry, allowing the simultaneous detection of more than 120 different parameters in single-cell resolution, will enable the identification of circulating cell subpopulations that might play a pivotal role in IRDs pathophysiology and their potential use as therapeutic targets.

Si-Miao-Yong-An Decoction alleviates thromboangiitis obliterans by regulating miR-548j-5p/IL-17A signaling pathway

Thromboangiitis obliterans (TAO) is a rare, chronic, progressive, and segmental inflammatory disease characterized by a high rate of amputation, significantly compromising the quality of life of patients. Si-Miao-Yong-An decoction (SMYA), a traditional prescription, exhibits anti-inflammatory, anti-thrombotic, and various other pharmacological properties. Clinically, it was fully proved to be effective for TAO therapy, but the specific therapeutic effect of SMYA on TAO has been unknown. Thus, deep unveiling the mechanism of SMYA in TAO for identifying clinical therapeutic targets is extremely important. In this study, we observed elevated levels of IL-17A in the peripheral blood mononuclear cells (PBMCs) of TAO patients, whereas the expression of miR-548j-5p was significantly decreased. A negative correlation between the levels of miR-548j-5p and IL-17A was also demonstrated. In vitro experiments showed that overexpression of miR-548j-5p led to a decrease in IL-17A levels, whereas downregulation of miR-548j-5p showed the opposite effect. Using a dual luciferase assay, we confirmed that miR-548j-5p directly targets IL-17A. Furthermore, serum containing SMYA effectively decreased IL-17A levels by increasing the expression of miR-548j-5p. More importantly, the results of in vivo tests indicated that SMYA mitigated the development of TAO by inhibiting IL-17A through the upregulation of miR-548j-5p in vascular tissues. In conclusion, SMYA significantly enhances the expression of miR-548j-5p, thereby reducing the levels of the target gene IL-17A and alleviating TAO. Our research not only identifies novel targets and pathways for the clinical diagnosis and treatment of TAO but also advances the innovation in traditional Chinese medicine through the elucidation of the SMYA/miR-548j-5p/IL-17A regulatory axis in the pathogenesis of TAO.

An update in the pharmacological management of axial spondyloarthritis

INTRODUCTION

Significant progress has been made in the diagnosis and management of axial spondyloarthritis (AxSpA) over recent decades. A greater understanding of the immunopathogenesis of the disease has paved the way for the development of targeted treatments. Their efficacy has been demonstrated in randomized controlled trials, meta-analyses and one head-to-head study of biologic DMARDs. Treatment decisions in AxSpA are currently influenced by patient choice, co-morbidity, clinician familiarity and cost.

AREAS COVERED

We review the clinical trials that underpin the evidence base for treatments in AxSpA. We also cover the meta-analyses and head-to-head data that seek to support clinicians in personalizing treatment decisions. Further, we discuss the recent international guidelines that provide clinicians with treatment pathways and guidance.

EXPERT OPINION

We conclude that treatment decisions in managing both radiographic and non-radiographic AxSpA should be based on shared decision-making with patients, the clinical effectiveness of drug class, co-morbidity and cost. At present, we have limited head-to-head data to prioritize one drug class over another for first-line treatment but can recommend tumor necrosis factor (TNF), interleukin 17 (IL17) and JAK inhibition as being comparable in terms of clinical, structural and patient-reported outcome measures. Further real-world data may guide treatment decision-making in individual patients.

Pro-inflammatory cytokines in spondyloarthritis: a case-control study

OBJECTIVES

We aimed to determine the discriminative values of pro-inflammatory cytokines to distinguish spondyloarthritis patients from healthy subjects and to assess the association between these cytokines and spondyloarthritis characteristics.

METHODS

We conducted a case-control study, including 144 subjects matched for age and sex: 72 spondyloarthritis patients(G1) and 72 controls (G2). The disease activity was assessed using ASDAS-CRP and BASDAI. Structural damage was assessed using BASRI. The levels of interleukin (IL) IL-1, IL-6, IL-8, IL-17, IL-23, and tumor necrosis factor α(TNFα) were measured.

RESULTS

Each group included 57 men. The mean age was 44.84 ± 13.42 years. Except for IL-8, all cytokine levels were significantly higher in patients compared to controls (IL-1: p = 0.05, IL-6: p = 0.021, TNFα: p = 0.039, IL-17 and IL-23: p < 0.001). Cutoff values of IL-17 and IL-23 distinguishing patients in G1 from those in G2 were 17.6 and 7.96 pg/mL, respectively. TNFα level correlated to BASDAI (p = 0.029) and BASRI (p = 0.002). Multivariate analysis showed that structural damage was associated with the male gender (p = 0.017), longer disease duration (p = 0.038), and high disease activity (p = 0.044). Disease activity was associated with longer disease duration (p = 0.012) and increased IL-6 levels (p = 0.05).

CONCLUSION

Our study showed that IL-17 was the ablest to distinguish between spondyloarthritis patients and controls, suggesting that IL-17 may be helpful for the diagnosis of spondyloarthritis.

Hematological indices in psoriatic enthesopathy: relation to clinical and ultrasound evaluation

BACKGROUND

Enthesopathy is considered a crucial aspect of assessment and outcome in psoriatic arthritis (PsA). Musculoskeletal ultrasound (MSUS) is a critical tool for accurately detecting enthesitis. Recent research focuses on identifying simple biomarkers for detecting and monitoring psoriatic enthesopathy. Red cell distribution width (RDW), mean platelet volume (MPV), and neutrophil/lymphocyte ratio (NLR) are components of a complete blood count (CBC) and are reliable bio-inflammatory markers in various rheumatic diseases.

AIM OF WORK

To measure MPV, RDW, and NLR in psoriatic enthesopathy and determine their relationship to disease activity and MSUS findings.

PATIENTS AND METHODS

This study focused on 30 people with psoriatic arthritis (PsA) as per CASPAR criteria, along with 20 control subjects. Enthesopathy was evaluated clinically using the Leeds Enthesitis Index (LEI). The modified Disease Activity Index of Psoriatic Arthritis (DAPSA28) was calculated, and RDW, MPV, NLR, CRP, and ESR were measured. Each enthesis in LEI was radiologically assessed using plain radiography and MSUS according to OMERACT definitions.

RESULTS

There was a significant relationship between clinical tenderness, the presence of enthesophytes on plain radiography, and MSUS findings at entheses sites (p < 0.001 for each). Psoriatic patients had higher levels of RDW and MPV (p < 0.001 and 0.01, respectively) than controls, with no significant differences in NLR (p = 0.189) between the two groups. RDW and MPV levels were positively correlated with the DAPSA28 score.

CONCLUSION

Monitoring PsA disease activity can be improved by considering RDW and MPV as reliable indicators and using them to screen for psoriatic enthesopathy with MSUS indices. Key points • Clinically identifying enthesitis in patients with PsA can be challenging. Imaging MSUS indices hold promise for objective analysis, but there is no consensus on which indices to use in clinical trials and daily practice. • Patients with psoriatic enthesopathy have higher RDW and MPV levels, which are positively correlated with DAPSA28 score. • RDW and MPV can be considered in the turn of improved screening of psoriatic enthesopathy with MSUS scores.

Associations of inflammatory cytokines with palmoplantar pustulosis: a bidirectional Mendelian randomization study

Background

Variations in circulatory cytokine levels have been observed during the onset and course of palmoplantar pustulosis (PPP); however, whether these changes are due to etiological or secondary factors is unclear. To clarify the causal relationship, we conducted a summarized-level bidirectional Mendelian randomization (MR) analysis in this study.

Methods

A FinnGen biobank genome-wide association study (GWAS) of 212,766 individuals (524 PPP patients and 212,242 controls) provided summary data for PPP, whereas genetic instrumental variables (IVs) linked to circulation cytokine levels were gathered from a GWAS of 14,824 European individuals. The inverse-variance weighted (IVW), weighted median (WME), simple mode, and MR-Egger methods were used to ascertain the changes in PPP pathogenic cytokine taxa. Sensitivity analysis, which included horizontal pleiotropy analysis, was then conducted. The reliability of the results was assessed using the leave-one-out approach and the MR Steiger test, which evaluated the strength of a causal relationship. To evaluate the reverse causality between PPP and circulating cytokine levels, a reverse MR analysis was carried out.

Results

Our study demonstrated positive associations between C-X-C motif chemokine 6 (CXCL6) and PPP (odds ratio, OR 1.257, 95%CI: 1.001-1.570, p = 0.043). C-C motif chemokine 19 (CCL19) and interleukin-6 (IL-6) were suggested to be protectively associated with the development of PPP (OR: 0.698,95% CI: 0.516-0.944, p = 0.020; OR: 0.656, 95%CI:0.437-0.985, p = 0.042). The results were steady after sensitivity and heterogeneity analyses.

Conclusion

At the genetic prediction level, we identified causally connected inflammation-related variables that contributed to the onset and development of PPP. The therapeutic options for some refractory PPP have expanded due to tailored cytokine therapy, generating fresh concepts for PPP diagnostics and mechanism investigation.

Roles of IRF4 in various immune cells in systemic lupus erythematosus

Interferon regulatory factor 4 (IRF4) is a member of IRF family of transcription factors which mainly regulates the transcription of IFN. IRF4 is restrictively expressed in immune cells such as T and B cells, macrophages, as well as DC. It is essential for the development and function of these cells. Since these cells take part in the homeostasis of the immune system and dysfunction of them contributes to the initiation and progress of systemic lupus erythematosus (SLE), the roles of IRF4 in the SLE development becomes an important topic. Here we systemically discuss the biological characteristics of IRF4 in various immune cells and analyze the pathologic effects of IRF4 alteration in SLE and the potential targeting therapeutics of SLE.

Secukinumab for children and adolescents with enthesitis-related arthritis and psoriatic arthritis: lessons from treatment in adults and the way forward

INTRODUCTION

Targeting IL-17A using Secukinumab, a humanized monoclonal immunoglobulin G1 (IgG1)/κ against IL-17A is a therapeutic option for immune-mediated disorders such as psoriasis and ankylosing spondylitis. The US Food and Drug Administration and the European Medicines Agency have approved it for the treatment of moderate to severe plaque psoriasis, active psoriatic arthritis, ankylosing spondylitis, and non-radiographic axial spondylarthritis. Recently it has also been approved for use in children with severe plaque psoriasis, active psoriatic arthritis, and enthesitis-related arthritis.

AREAS COVERED

This review focuses on the role of Secukinumab in the management of children and adolescents with enthesitis-related arthritis and psoriatic arthritis. We discuss the salient findings of pivotal RCTs and other studies supporting the use of Secukinumab in adults and children, in particular, focusing on its safety and efficacy.

EXPERT OPINION

Secukinumab is a therapeutic target for psoriasis, psoriatic arthritis, and spondyloarthropathies in both adults and children. No major safety signals are observed with its use in short-term follow-up. Thus far, Secukinumab has not been found to significantly increase the risk of tuberculosis (TB).

Effectiveness of secukinumab in patients with psoriasis and psoriatic arthritis in a Saudi real-world setting

INTRODUCTION

Psoriasis (PsO) is an immune-mediated chronic inflammatory disease that results in severe outcomes that impact the patient's quality of life and work productivity. We investigated the effectiveness of secukinumab in patients with chronic plaque psoriasis and psoriatic arthritis (PsA) over a 12-month period.

METHODS

This was a longitudinal, retrospective study of the medical records of 81 patients with psoriasis and/or psoriatic arthritis who had been treated with secukinumab for at least 12 weeks.

RESULTS

The Psoriasis Area Severity Index (PASI), Body Surface Area (BSA) percentage, and Dermatology Quality of Life Index (DLQI) among patients with PsO and PsO-PsA showed a statistically significant decrease from baseline over 12 months by approximately 9.86, 19.3%, and 9.7, respectively (p values < 0.001 for each). Moreover, there was a statistically significant decrease in the overall Disease Activity in Psoriatic Arthritis score (DAPSA) by approximately 22.35 from baseline over 12 months of treatment (p < 0.001). Considering the patients who started secukinumab 12 months or more prior to the study cutoff date, the 12-month retention rate was 85%.

CONCLUSION

In a Saudi real-world setting, secukinumab proved to be an efficient medication with high efficacy and retention rates.

The role of ixekizumab in the treatment of nonradiographic axial spondyloarthritis

Nonradiographic axial spondyloarthritis (nr-axSpA) is a subtype of SpA with undeveloped definite radiographic sacroiliitis. Tumor necrosis factor inhibitors have demonstrated effectiveness in nr-axSpA patients who do not respond to first-line therapy. More recently, accumulated data from genetic, experimental, and clinical studies revealed that IL-17 is a key player in the pathogenesis of SpA, leading to development of new biologics directly inhibiting IL-17. Among them, ixekizumab is a high-affinity monoclonal antibody that selectively targets IL-17A and has exhibited significant efficacy and acceptable safety profiles in the treatment of nr-axSpA. The aim of this paper is to narratively review the recent insights of IL-17 in the pathogenesis of axSpA and discuss the effectiveness and safety of ixekizumab in treatment of nr-axSpA.

Patients with ankylosing spondylitis present a distinct CD8 T cell subset with osteogenic and cytotoxic potential

OBJECTIVES

Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease affecting mainly the axial skeleton. Peripheral involvement (arthritis, enthesitis and dactylitis) and extra-musculoskeletal manifestations, including uveitis, psoriasis and bowel inflammation, occur in a relevant proportion of patients. AS is responsible for chronic and severe back pain caused by local inflammation that can lead to osteoproliferation and ultimately spinal fusion. The association of AS with the human leucocyte antigen-B27 gene, together with elevated levels of chemokines, CCL17 and CCL22, in the sera of patients with AS, led us to study the role of CCR4+ T cells in the disease pathogenesis.

METHODS

CD8+CCR4+ T cells isolated from the blood of patients with AS (n=76) or healthy donors were analysed by multiparameter flow cytometry, and gene expression was evaluated by RNA sequencing. Patients with AS were stratified according to the therapeutic regimen and current disease score.

RESULTS

CD8+CCR4+ T cells display a distinct effector phenotype and upregulate the inflammatory chemokine receptors CCR1, CCR5, CX3CR1 and L-selectin CD62L, indicating an altered migration ability. CD8+CCR4+ T cells expressing CX3CR1 present an enhanced cytotoxic profile, expressing both perforin and granzyme B. RNA-sequencing pathway analysis revealed that CD8+CCR4+ T cells from patients with active disease significantly upregulate genes promoting osteogenesis, a core process in AS pathogenesis.

CONCLUSIONS

Our results shed light on a new molecular mechanism by which T cells may selectively migrate to inflammatory loci, promote new bone formation and contribute to the pathological ossification process observed in AS.

Is tapering or discontinuation of biologic treatment in patients with radiographic and nonradiographic axial spondyloarthritis reasonable? : A local cohort study

OBJECTIVE

We retrospectively determined factors predicting biologic treatment discontinuation or tapering in patients with axSpA.

MATERIALS AND METHODS

We included 63 nonradiographic axSpA (nr-axSpA) and 138 radiographic axSpA (r-axSpA) patients on biologic treatments for at least 1 year. The biologic dosing intervals were increased in patients who had been in remission for at least 6 months. In patients whose biologic dosing intervals could be increased by 100% for at least 6 months, the agents were stopped at the end of that time. In patients for whom the biologic agents were stopped or tapered, relapse was defined as a Bath Ankylosing Spondylitis Disease activity index score > 4 and a CRP level > 10 mg/L.

RESULTS

The median duration of biologic treatment (all patients) was 2 (1-11) years. Logistic regression analysis did not identify any independent predictor of treatment discontinuation. NSAID use was the only independent predictor of tapering (p = 0.001). The time to relapse after tapering was shorter in patients with r‑axSpA than nr-axSpA (25.97 vs. 39.53 months; p = 0.05). The time to relapse in patients with r‑axSpA was considerably shorter than that in patients with nr-axSpA (5.14 vs. 13 months; p = 0.001). All r‑axSpA patients relapsed over the follow-up period; only 2 nr-axSpA patients did not relapse.

CONCLUSION

The most significant independent predictor of relapse was NSAID use during treatment. For axSpA patients in remission, tapering of the biologic dosing intervals is more appropriate than discontinuation.

Assessment of safety profile of secukinumab in real-world scenario using United States food and drug administration adverse event reporting system database

Secukinumab is an anti-IL-17 monoclonal antibody approved for treating psoriasis and various arthritides. A comprehensive evaluation of its safety, especially in a real-world setting, is necessary. This study aimed to describe the adverse events (AE) associated with secukinumab use using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database. FAERS data files containing AE reports from 2015 to 2021 were downloaded for data mining. Primary or secondary suspect medications indicated for psoriasis were identified and analyzed. Medical dictionary for regulatory activities (MedDRA version 24.1) was used to analyze the AE terms. To detect potential safety signals of AE from secukinumab use, disproportionality analysis was used. A total of 365,590 adverse event reports were identified; of these, 44,761 reports involved the use of secukinumab. Safety signals were identified for ocular infections and gastrointestinal adverse events at the standardised MedDRA query level. Safety signals for oral candidiasis, oral herpes, conjunctivitis, eye infections, and ulcerative colitis were identified at the preferred term level. The findings of our study are consistent with those of earlier studies, such as the increased risk of infections and inflammatory bowel disease. However, our study also identified additional safety signals that need to be further evaluated.

Clinically relevant differences in spinal mobility related to daytime performance in patients with axial spondyloarthritis

OBJECTIVE

Patients with axial spondyloarthritis (axSpA) suffer from clinical symptoms like morning stiffness and back pain. Mobility of patients with axSpA is often impaired. The aim of this study is to compare the performance of patients with axSpA regarding mobility measures including performance-based tests and objective electronic assessments with the Epionics SPINE device (ES) at different times of the day compared with healthy controls (HC).

METHODS

Observational trial, consecutive inpatients with axSpA (n=100) and 20 HCs were examined in the morning (V1: before 10:00 am) and in the afternoon (V2: after 02:00 pm) by the Bath Ankylosing Spondylitis Metrology Index (BASMI), the AS physical performance index (ASPI), the Short Physical Performance Battery (SPPB) and ES measurements, including range of motion (RoM) and range of kinematics (RoK).

RESULTS

The assessments of patients with axSpA performed in the morning clearly differed from those in the afternoon, especially regarding performance-based tests. Significant improvements were seen for BASMI (4.0±3.8 to 3.8±1.9; p<0.001), ASPI (36.2±18.3 to 28.8±11.9 s; p<0.001), SPPB (10.1±1.5 to 10.7±1.4 points; p<0.001) and for ES measures of speed (RoK; p<0.018) but not for RoM, except for lateral flexion (13.3±7.4 to 14.7±8.2°; p=0.002). This time of assessment-related variability was not observed in HC.

CONCLUSION

The spinal mobility of patients with axSpA was worse in the morning but significantly improved in the afternoon. This was captured best by performance-based measures and was not seen in HC. The diurnal variation of mobility has implications for clinical studies, suggesting that the time of assessments needs to be standardised.

Immune cells in the epithelial immune microenvironment of psoriasis: emerging therapeutic targets

Psoriasis is a chronic autoimmune inflammatory disease characterized by erroneous metabolism of keratinocytes. The development of psoriasis is closely related to abnormal activation and disorders of the immune system. Dysregulated skin protective mechanisms can activate inflammatory pathways within the epithelial immune microenvironment (EIME), leading to the development of autoimmune-related and inflammatory skin diseases. In this review, we initially emphasized the pathogenesis of psoriasis, paying particular attention to the interactions between the abnormal activation of immune cells and the production of cytokines in psoriasis. Subsequently, we delved into the significance of the interactions between EIME and immune cells in the emergence of psoriasis. A thorough understanding of these immune processes is crucial to the development of targeted therapies for psoriasis. Finally, we discussed the potential novel targeted therapies aimed at modulating the EIME in psoriasis. This comprehensive examination sheds light on the intricate underlying immune mechanisms and provides insights into potential therapeutic avenues of immune-mediated inflammatory diseases.

Disease characteristics, pathogenesis, and treatment controversies of axial psoriatic arthritis

Axial psoriatic arthritis (axPsA) has considerable overlap with axial spondyloarthritis (axSpA) but has some unique features that sometimes preclude classification into axSpA. It has some clinical and radiographic differences compared to axSpA. Imaging typically shows asymmetric syndesmophytes, mainly in the cervical spine, with less frequent sacroiliitis. It more commonly presents later in life and is associated with less severe inflammatory back pain than axSpA. The interleukin (IL) IL-23/IL-17 axis is central to the pathogenesis of both diseases. However, the response to therapies targeting these cytokines has been different. IL-23 inhibitors are ineffective in axSpA but may be effective in psoriatic arthritis (PsA). Recent post hoc analyses of clinical trial data with IL-23 inhibitors in PsA have raised the possibility of their efficacy in axPsA and need evaluation in future clinical trials. Moreover, there is a need for classification criteria for axPsA and better tools to assess therapeutic response.

Shared and Distinct Gut Microbiota in Spondyloarthritis, Acute Anterior Uveitis, and Crohn's Disease

OBJECTIVE

Spondyloarthritis (SpA) is a group of immune-mediated diseases highly concomitant with nonmusculoskeletal inflammatory disorders, such as acute anterior uveitis (AAU) and Crohn's disease (CD). The gut microbiome represents a promising avenue to elucidate shared and distinct underlying pathophysiology.

METHODS

We performed 16S ribosomal RNA sequencing on stool samples of 277 patients (72 CD, 103 AAU, and 102 SpA) included in the German Spondyloarthritis Inception Cohort and 62 back pain controls without any inflammatory disorder. Discriminatory statistical methods were used to disentangle microbial disease signals from one another and a wide range of potential confounders. Patients were naive to or had not received treatment with biological disease-modifying antirheumatic drugs (DMARDs) for >3 months before enrollment, providing a better approximation of a true baseline disease signal.

RESULTS

We identified a shared, immune-mediated disease signal represented by low abundances of Lachnospiraceae taxa relative to controls, most notably Fusicatenibacter, which was most abundant in controls receiving nonsteroidal antiinflammatory drug monotherapy and implied to partially mediate higher serum C-reactive protein. Patients with SpA showed an enrichment of Collinsella, whereas human leukocyte antigen (HLA)-B27+ individuals displayed enriched Faecalibacterium. CD patients had higher abundances of a Ruminococcus taxon, and previous conventional/synthetic DMARD therapy was associated with increased Akkermansia.

CONCLUSION

Our work supports the existence of a common gut dysbiosis in SpA and related inflammatory pathologies. We reveal shared and disease-specific microbial associations and suggest potential mediators of disease activity. Validation studies are needed to clarify the role of Fusicatenibacter in gut-joint inflammation, and metagenomic resolution is needed to understand the relationship between Faecalibacterium commensals and HLA-B27.

Human in vitro-induced IL-17A+ CD8+ T-cells exert pro-inflammatory effects on synovial fibroblasts

IL-17A+ CD8+ T-cells, termed Tc17 cells, have been identified at sites of inflammation in several immune-mediated inflammatory diseases. However, the biological function of human IL-17A+ CD8+ T-cells is not well characterized, likely due in part to the relative scarcity of these cells. Here, we expanded IL-17A+ CD8+ T-cells from healthy donor PBMC or bulk CD8+ T-cell populations using an in vitro polarization protocol. We show that T-cell activation in the presence of IL-1β and IL-23 significantly increased the frequencies of IL-17A+ CD8+ T-cells, which was not further enhanced by IL-6, IL-2, or anti-IFNγ mAb addition. In vitro-generated IL-17A+ CD8+ T-cells displayed a distinct type-17 profile compared with IL-17A- CD8+ T-cells, as defined by transcriptional signature (IL17A, IL17F, RORC, RORA, MAF, IL23R, CCR6), high surface expression of CCR6 and CD161, and polyfunctional production of IL-17A, IL-17F, IL-22, IFNγ, TNFα, and GM-CSF. A significant proportion of in vitro-induced IL-17A+ CD8+ T-cells expressed TCRVα7.2 and bound MR1 tetramers indicative of MAIT cells, indicating that our protocol expanded both conventional and unconventional IL-17A+ CD8+ T-cells. Using an IL-17A secretion assay, we sorted the in vitro-generated IL-17A+ CD8+ T-cells for functional analysis. Both conventional and unconventional IL-17A+ CD8+ T-cells were able to induce pro-inflammatory IL-6 and IL-8 production by synovial fibroblasts from patients with psoriatic arthritis, which was reduced upon addition of anti-TNFα and anti-IL-17A neutralizing antibodies. Collectively, these data demonstrate that human in vitro-generated IL-17A+ CD8+ T-cells are biologically functional and that their pro-inflammatory function can be targeted, at least in vitro, using existing immunotherapy.

Current Pharmacological Therapies for the Management of Spondyloarthritis: Special Considerations in Older Patients

Spondylarthritis (SpA) is generally observed in young male patients but can be diagnosed in older patients. These cases correspond to late-onset SpA (LoSpA) with two main clinical presentations, axial and peripheral SpA. Another increasingly common situation is that of older patients who have had SpA for many years. The therapeutic management of LoSpA is quite smilar to the management of patients with an early-onset disease, combining both non-pharmacological and pharmacological treatments. The treatments that can be used in LoSpA include non-steroidal anti-inflammatory drugs (NSAIDs) and biological agents targeting TNFα or IL-17A. Janus kinase inhibitors (JAKi) were recently introduced on the market for SpA. TNF inhibitors and IL-17inhibitors are very effective drugs in early-onset SpA. The effectiveness and safety of targeted therapies have not been specifically evaluated in LoSpA or older patients, and thus caution is required for these patients with comorbidities and/or polymedication. According to indirect data, biological agents seem to be less effective in LoSpA compared with early-onset disease. In parallel, a careful evaluation for the risk of infection, malignancy and cardiovascular events is recommended before initiating these drugs in this age category. JAKi may be used in LoSpA, but only in selected patients according to recent recommendations from the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA). When considering that the prevalence of such situations is expected to increase as ageing progresses, it is certainly time to consider this patient category as a distinct subgroup within the spectrum of SpA. Specific studies evaluating targeted agents in this age category are thus desirable.

Interleukin-17 and inflammatory bowel disease: a 2-sample Mendelian randomization study

Introduction

Observational studies have discovered a contradictory phenomenon between interleukin-17 (IL-17) and inflammatory bowel disease (IBD). The study aimed to confirm the causal association between each subtype of IL-17 and IBD.

Methods

We performed a 2-sample univariable and multivariable mendelian randomization (MR) to determine which subtype of IL-17 is causally related to IBD and its subtypes, and used a series of sensitivity analysis to examine the reliability of the main MR assumptions.

Results

We found that IL-17B, IL-17E and IL-17RB were significantly associated with an increased risk of UC (IL-17B: OR: 1.26, 95% CI, 1.09-1.46, P < 0.01; IL-17E: OR: 1.17, 95% CI, 1.05-1.30, P < 0.01; IL-17RB: OR: 1.30, 95% CI, 1.20-1.40, P < 0.0001) while IL-17C and IL-17RC showed causal effects on the increased risk of CD (IL-17C: OR: 1.23, 95% CI, 1.21-1.26, P < 0.0001; IL-17RC: OR: 2.01, 95% CI, 1.07-3.75, P=0.03). The results of multivariable MR (MVMR) showed that the causal effects of IL-17B and IL-17E on UC were unilaterally dependent on IL-17RB, while the effects of IL-17C and IL-17RC on CD were interdependent.

Discussion

Our study provided new genetic evidence for the causal relationships between each subtype of IL-17 and IBD, promoting future mechanistic research in IBD.

Aberrant expression of interleukin-17A in mast cells contributes to the pathogenesis of hidradenitis suppurativa

BACKGROUND

Hidradenitis suppurativa (HS) significantly diminishes the quality of life for patients. Delayed diagnosis represents a significant challenge in effectively managing HS.

OBJECTIVES

To identify and characterize the key mediator in HS.

METHODS

Bioinformatic transcriptomic analysis was applied to identify potential candidates contributing to the disease process of HS. Skin samples from 40 patients with HS, four with psoriasis and 29 with normal skin were included. The expression of interleukin (IL)-17A was evaluated and compared among samples of normal skin, psoriatic skin and skin from different stages of HS by immunohistochemistry or dual-colour immunofluorescence. In vitro experiments and RNA sequencing analysis were also conducted to validate the expression of IL-17A and its pathogenic effect in HS.

RESULTS

Transcriptomic database analyses identified IL-17 signalling as a potential contributor to HS. In HS, the predominant IL-17A+ cell population was identified as mast cells. IL-17A+ mast-cell density was significantly elevated in HS, especially in samples with advanced Hurley stages, compared with normal skin and psoriasis samples. The close contact between IL-17A+ mast cells and IL-17 receptor A (IL-17RA)-expressing keratinocytes was demonstrated, along with the significant effects of IL-17A on keratinocyte cell proliferation and HS pathogenic gene expression. Treatment with biologics (brodalumab or adalimumab) reduced the severity of the disease and the number of IL-17A+ mast cells in affected tissues.

CONCLUSIONS

The presence of high-density IL-17A+ mast cells may serve as a valuable pathological marker for diagnosing HS. Moreover, developing therapeutic drugs targeting IL-17A+ mast cells may provide a new approach to treating HS.

Microbiota-dependent indole production is required for the development of collagen-induced arthritis

Altered tryptophan catabolism has been identified in inflammatory diseases like rheumatoid arthritis (RA) and spondyloarthritis (SpA), but the causal mechanisms linking tryptophan metabolites to disease are unknown. Using the collagen-induced arthritis (CIA) model we identify alterations in tryptophan metabolism, and specifically indole, that correlate with disease. We demonstrate that both bacteria and dietary tryptophan are required for disease, and indole supplementation is sufficient to induce disease in their absence. When mice with CIA on a low-tryptophan diet were supplemented with indole, we observed significant increases in serum IL-6, TNF, and IL-1β; splenic RORγt+CD4+ T cells and ex vivo collagen-stimulated IL-17 production; and a pattern of anti-collagen antibody isotype switching and glycosylation that corresponded with increased complement fixation. IL-23 neutralization reduced disease severity in indole-induced CIA. Finally, exposure of human colon lymphocytes to indole increased expression of genes involved in IL-17 signaling and plasma cell activation. Altogether, we propose a mechanism by which intestinal dysbiosis during inflammatory arthritis results in altered tryptophan catabolism, leading to indole stimulation of arthritis development. Blockade of indole generation may present a novel therapeutic pathway for RA and SpA.

Neutrophil function following treatment of psoriatic arthritis patients with secukinumab: altered cytokine signalling but no impairment of host defence

OBJECTIVES

Identifying that dysfunction of the IL-23/17 axis underlies PsA has led to the development of effective targeted therapies such as the IL-17A inhibitor secukinumab. As IL-17A stimulates the secretion of neutrophil chemoattractants, such as CXCL8 (IL-8), we examined the effect of secukinumab on neutrophil function in PsA.

METHODS

Nineteen patients with active PsA were treated with secukinumab. Clinical response [PsA Response Criteria (PsARC) and Psoriasis Area and Severity Index (PASI)] and peripheral blood neutrophil function (apoptosis, receptor expression, phagocytosis/killing, chemotaxis and RNA expression) were measured at 12 week intervals for 48 weeks and compared with age- and sex-matched healthy controls.

RESULTS

At 12 weeks, 12/16 (75%) patients had a PsARC response (100% at 36 weeks) and 10/14 (71%) achieved a 90% PASI response. At baseline, there were no differences in PsA neutrophil reactive oxygen species generation, constitutive or cytokine-delayed apoptosis, chemotaxis or phagocytosis of opsonized Staphylococcus aureus compared with healthy controls. Similarly, there were no differences in these functions from baseline to 12 weeks of therapy. However, surface levels of CD11b/CD18 and CD63 increased and expression of CD16 decreased during therapy. In addition, in a subgroup of early (12 week) responders to secukinumab, RNA sequencing revealed transcriptome changes predicting down-regulation of cytokine signalling and chemotaxis pathways and up-regulation of de novo gene expression pathways, including translation initiation, mRNA catabolism and translation.

CONCLUSION

Complex changes in the properties of circulating neutrophils occur with secukinumab treatment in PsA that may indicate altered responsiveness to changes in both local and systemic levels of pro-inflammatory cytokines. However, host defence processes of neutrophils were unaltered.

RORγt inhibition ameliorates IL-23 driven experimental psoriatic arthritis by predominantly modulating γδ-T cells

OBJECTIVE

Divergent therapeutic outcomes on different disease domains have been noted with IL-23 and IL-17A-blockade in PsA. Therefore, elucidating the role of RORγt, the master regulator of type 17 immune responses, is of potential therapeutic interest. To this end, RORγt inhibition was assessed in combined skin, joint and gut inflammation in vivo, using a PsA model.

METHODS

We tested the efficacy of a RORγt antagonist in B10.RIII mice challenged with systemic overexpression of IL-23 by hydrodynamic injection of IL-23 enhanced episomal vector (IL-23 EEV). Clinical outcomes were evaluated by histopathology. Bone density and surface erosions were examined using micro-computed tomography. Cytokine production was measured in serum and by intracellular flow cytometry. Gene expression in PsA-related tissues was analysed by qPCR.

RESULTS

RORγt-blockade significantly ameliorated psoriasis, peripheral arthritis and colitis development in IL-23 EEV mice (improvement of clinical scores and weight loss respectively by 91.8%, 58.2% and 7.0%, P < 0.001), in line with profound suppression of an enhanced type IL-17 immune signature in PsA-affected tissues. Moreover, inflammation-induced bone loss and bone erosions were reduced (P < 0.05 in calcaneus, P < 0.01 in tibia). Sustained IL-23 overexpression resulted in only mild signs of sacroiliitis. Gamma-delta (γδ)-T cells, the dominant source of T cell-derived IL-17A and IL-22, were expanded during IL-23 overexpression, and together with Th17 cells, clearly countered by RORγt inhibition (P < 0.001).

CONCLUSION

RORγt-blockade shows therapeutic efficacy in a preclinical PsA model with protection towards extra-musculoskeletal manifestations, reflected by a clear attenuation of type 17 cytokine responses by γδ-T cells and Th17 cells.