The IL-23/IL-17 axis in psoriatic arthritis

Pathogenesis of psoriatic arthritis: new insights from a bone marrow perspective

PURPOSE OF REVIEW

Psoriatic arthritis is an immune-mediated disease that primarily affects the skin and joints. It falls under the umbrella term of rheumatic diseases, which describes a group of closely related yet distinct disorders with many common underlying molecular pathways. Despite the distinct clinical manifestation of each disorder, the shared therapeutic strategies attest to the commonality of cellular and molecular underpinnings. Herein we provide a concise yet comprehensive overview of the interleukin (IL)-23/IL-17 axis and its involvement in mechanistic pathways leading to the pathogenesis of this dual skin and joint clinical manifestation which is characteristic of psoriatic arthritis and other rheumatic diseases.

RECENT FINDINGS

The interconnection between activated innate immune cells and adaptive immunity has transformed current thinking to include other organs such as the bone marrow as potential tissue of disease origin. A plethora of animal models and genetic studies converge on the critical role of IL-23/IL-17 axis, and highlight the importance of myeloid cell activation as common pathways between autoinflammatory and autoimmune diseases and chronic inflammation. These findings underscore the intricate immune mechanisms involved in inflammatory arthritis and highlight molecular mechanisms in disease pathogenesis.

SUMMARY

These insights pave the way for the development of novel diagnostic and therapeutic strategies, with a focus on translating these findings into improved clinical practice.

Tyrosine kinase 2 inhibitors: Synthesis and applications in the treatment of autoimmune diseases

Janus kinase (JAK), a class of non-receptor tyrosine kinases, are essential in modulating the cytokine signaling cascade of cytokines associated with immune responses. Despite their potential in the treatment of autoimmune diseases, JAK inhibitors are associated with safety concerns, regarding cytokine suppression and significant side effects. Tyrosine kinase 2 (TYK2), a prominent member of the JAK family, is central to the signaling of interleukins (ILs) and interferons (IFNs), such as IL-12, IL-23 and IFNs. Targeted TYK2 inhibitors that specifically target the Janus Homology 1 (JH1) and pseudokinase (JH2) domains show enhanced specificity. JH1 acts as an ATP-competitive inhibitor, while JH2 acts as an allosteric regulator, contributing to reduced systemic side effects and improved therapeutic outcomes in clinical settings. This review summarizes the recent advances on the synthetic strategies of TYK2 inhibitors and their applications in the treatment of autoimmune diseases.

The neuroimmune mechanism of pain induced depression in psoriatic arthritis and future directions

Patients suffering from psoriatic arthritis (PsA) often experience depression due to chronic joint pain, which significantly hinders their recovery process. However, the relationship between these two conditions is not well understood. Through a review of existing studies, we revealed that certain neuroendocrine hormones and neurotransmitters are involved in the neuroimmune interactions related to both PsA and depression. These include adrenocorticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH), cortisol, monoamine neurotransmitters, and brain-derived neurotrophic factor (BDNF). Notably, the signalling pathway involving CRH, MCs, and Th17 cells plays a crucial role in linking PsA with depression; thus, this pathway may help clarify their connection. In this review, we outline the inflammatory immune changes associated with PsA and depression. Additionally, we explore how neuroendocrine hormones and neurotransmitters influence inflammatory responses in these two conditions. Finally, our focus will be on potential treatment strategies for patients with PsA and depression through the targeting of the CRH-MC-Th17 pathway. This review aims to provide a theoretical framework as well as new therapeutic targets for managing PsA alongside depression.

A Snapshot of Biomarkers in Psoriasis

A persistent long-standing, inflammatory skin condition that is brought on by a variety of factors is psoriasis. It is distinguished by itchy, scaly, reddish plaques, particularly on areas of the body that are frequently chafed, including the extensor sites of the limbs. Recent developments in molecular-targeted therapy that use biologics or small-molecule inhibitors can effectively cure even the worst psoriatic indications. The outstanding clinical outcomes of treatment help to clarify the disease's detrimental consequences on quality of life. Biomarkers that identify deep remission are essential for developing uniform treatment plans. Blood protein markers such as AMPs that are consistently quantifiable can be very helpful in routine clinical practice. The metabolic pathways involve biomarkers that can not only help diagnose psoriasis in a clinical setting but also indicate its severity based on the levels present in the body. Machine learning and AI have made a diagnosis of the expression of genes as biomarkers more accessible. In this article, biomarkers, as well as their key role in psoriasis, are discussed.

Guselkumab in Biologic-Naïve Patients with Active Psoriatic Arthritis in Russia: A Post Hoc Analysis of the DISCOVER-1 and -2 Randomized Clinical Trials

INTRODUCTION

There are limited data on the use of advanced therapies to treat psoriatic arthritis (PsA) in Russia. Guselkumab, an interleukin (IL)-23p19-subunit inhibitor, demonstrated efficacy in patients with PsA in the phase 3 DISCOVER-1 and -2, and COSMOS trials. This analysis evaluated the efficacy and safety of guselkumab in patients with PsA in Russia.

METHODS

This post hoc analysis of DISCOVER-1 and -2 included 1002 biologic-naïve patients with active PsA from Russia (n = 317) and the rest of the world (RoW; n = 685). Patients received guselkumab 100 mg every 4 weeks (Q4W), or at week 0 and 4 then Q8W, or placebo then guselkumab Q4W at week 24 (Russian: n = 119, 88, and 110, respectively; RoW: n = 216, 246, and 223, respectively). Outcomes through week 52 were pooled (DISCOVER-1 and -2); outcomes from week 52 to 100 represent DISCOVER-2 only.

RESULTS

In patients from Russia, ≥ 20% improvement in the American College of Rheumatology (ACR20) criteria response rates were higher with guselkumab vs. placebo at week 24, increased through week 52, and were consistent across all guselkumab-treated groups at week 100. Similar trends were generally observed for ACR50, ≥ 90% improvement in Psoriasis Area and Severity Index (PASI90), achievement of Disease Activity in Psoriatic Arthritis (DAPSA) low disease activity/remission and minimal disease activity, enthesitis and dactylitis resolution, ≥ 0.35 improvement in Health Assessment Questionnaire-Disability Index (HAQ-DI) score, improvement in patient-reported pain, and measures in patients with axial PsA (including Bath Ankylosing Spondylitis Disease Activity Index [BASDAI], Ankylosing Spondylitis Disease Activity Score [ASDAS], and patient-reported spinal pain). Efficacy responses were similar between patients from Russia and the RoW across all endpoints and timepoints. The safety profile of guselkumab in patients from Russia was consistent with previous findings.

CONCLUSION

This analysis demonstrated that the safety and efficacy profiles of guselkumab across all PsA domains and patient-reported outcomes in patients from Russia were similar to those in patients from the RoW.

TRIAL REGISTRATION NUMBERS

NCT03162796 and NCT03158285.

Association of the clinical components in the distal interphalangeal joint synovio-entheseal complex and subsequent response to ixekizumab or adalimumab in psoriatic arthritis

OBJECTIVES

To assess the frequency of simultaneous distal interphalangeal (DIP) joint disease and adjacent nail psoriasis (finger unit) among patients with psoriatic arthritis (PsA) and compare the efficacy of the IL-17A antagonist ixekizumab (IXE) and the TNF-α inhibitor adalimumab (ADA).

METHODS

This post hoc analysis evaluated the simultaneous occurrence of DIP joint involvement (tenderness and/or swelling) and adjacent nail psoriasis among patients with PsA from the SPIRIT-H2H (NCT03151551) trial comparing IXE to ADA. Among patients with simultaneous DIP joint involvement and adjacent nail psoriasis in ≥1 digit at baseline, treatment effects were assessed through week 52 for each affected finger unit; 'finger unit' defines the connected DIP joint and adjacent nail of an individual digit.

RESULTS

A total of 354 patients had simultaneous DIP joint involvement and adjacent nail psoriasis in ≥1 finger unit at baseline. Among them, 1309 (IXE: 639; ADA: 670) finger units had baseline DIP joint tenderness and/or swelling and adjacent nail psoriasis. Proportions of affected finger units achieving complete resolution were significantly higher with IXE vs ADA as early as week 12 (38.8% vs 28.4%, P < 0.0001) and at all post-baseline assessments through week 52 (64.9% vs 57.5%, P = 0.0055).

CONCLUSION

In this study cohort, patients with DIP joint involvement almost always had adjacent nail psoriasis. Greater resolution of DIP joint tenderness, swelling and adjacent nail psoriasis was achieved at all time points over 52 weeks through targeting IL-17A with IXE than TNF-α with ADA, which is noteworthy given prior comparable musculoskeletal outcomes for both drug classes.

Correlation of changes in inflammatory and collagen biomarkers with durable guselkumab efficacy through 2 years in participants with active psoriatic arthritis: results from a phase III randomized controlled trial

Background

Guselkumab (human monoclonal antibody) selectively inhibits the interleukin (IL)-23p19 subunit.

Objectives

Assess the longer-term pharmacodynamic effects of guselkumab and explore associations between such effects and clinical responses in patients with active psoriatic arthritis (PsA).

Design

DISCOVER-2 randomized 739 biologic-naïve patients with active PsA (swollen/tender joint counts each ⩾5, C-reactive protein (CRP) ⩾0.6 mg/dL) to guselkumab (100 mg every 4 weeks (Q4W) or at Weeks 0, 4, and then Q8W) or placebo. Guselkumab-randomized participants with available serum biomarker data (randomly selected to reflect demographic and disease characteristics of the DISCOVER-2 population) comprised inflammatory (N = 100) and collagen (N = 178) biomarker cohorts.

Methods

Pharmacodynamic effects of guselkumab through 2 years on inflammatory and collagen biomarker levels (general linear model) and associations between biomarkers and improvements in composite measures of joint, skin, and overall disease activity (Spearman linear regression) through 2 years were assessed. The relationship between the pharmacodynamic effects of guselkumab and achieving ⩾50% improvement in the American College of Rheumatology response criteria (ACR50) was assessed using a general linear model.

Results

With guselkumab, pharmacodynamic effects on inflammatory (CRP, IL-6, serum amyloid A (SAA), IL-17A, IL-17F, IL-22, and beta-defensin 2 (BD-2)) and collagen (matrix metalloproteinase-degradation type I, III, IV, and VI collagen (C1M, C3M, C4M, and C6M)) biomarker levels were sustained or enhanced through Week 100. Throughout follow-up timepoints (Week 24/52/100), decreases in CRP, IL-6, C1M, and C6M levels correlated (r = 0.26-0.30; p < 0.05) with improved joint disease activity (Disease Activity in Psoriatic Arthritis); decreases in IL-17A, IL-17F, IL-22, and BD-2 levels correlated (r = 0.34-0.58; p < 0.05) with improved skin disease (Psoriasis Area and Severity Index); and decreases in C1M, C3M, C4M, and C6M correlated (r = 0.27-0.31; p < 0.05) with improved overall disease activity (Psoriatic Arthritis Disease Activity Score). Significantly (p < 0.05) greater reductions from baseline at Week 100 in CRP, IL-6, SAA, and C1M levels were observed in participants improving from Week 24 ACR50 nonresponse to Week 100 ACR50 response and were accompanied by a significant decrease in C1M from Week 24 to Week 100 versus nonresponders at both Weeks 24 and 100.

Conclusion

In biologic-naïve participants with active PsA, guselkumab elicited substantial and enduring reductions in biomarkers that were associated with durable improvements in joint, skin, and overall disease activity through 2 years of DISCOVER-2.

Trial registration

NCT03158285 (clinicaltrials.gov identifier).

The immunologic role of IL-23 in psoriatic arthritis: a potential therapeutic target

INTRODUCTION

Psoriatic arthritis (PsA) is a debilitating chronic condition characterized by inflammation of the joints, bones, enthesis, and skin. The pivotal role of interleukin-23 (IL-23) in the pathogenesis of PsA has become increasingly evident. This proinflammatory cytokine is markedly elevated in patients with PsA, suggesting its potential as a therapeutic target. Consequently, IL-23 inhibitors have emerged as promising first-line biologic treatments for PsA.

AREAS COVERED

This review delves into the immunopathogenic mechanisms of IL-23 at the cellular and molecular levels in PsA. Furthermore, it provides the recent efficacy and safety profiles of IL-23 inhibitors. We conducted a literature search in PubMed for the following terms: 'IL-23 and psoriatic arthritis,' 'Ustekinumab,' 'Guselkumab,' 'Risankizumab,' and 'Tildrakizumab.' In addition, we retrieved clinical trials involving IL-23 inhibitors registered in ClinicalTrials.gov, EudraCT, and ICTRP.

EXPERT OPINION

Despite the promising outcomes observed with IL-23 inhibitors, several challenges persist. The long-term effects of these agents require further investigation through prospective studies, and their limited accessibility worldwide necessitates urgent attention. Additionally, ongoing research is warranted to explore other potential drug targets within the IL-23/IL-23 R axis. The development of reliable biomarkers could greatly enhance early detection, tailored management strategies, and personalized treatment approaches for patients with PsA.

The role of IL-17 and Th17 cells in keloid pathogenesis

Keloids are characterized histologically by excessive fibroblast proliferation and connective tissue deposition, and clinically by scar tissue extending beyond the original site of skin injury. These scars can cause pruritus, pain, physical disfigurement, anxiety, and depression. As a result, keloid patients often have a diminished quality of life with a disproportionate burden on ethnic minorities. Despite advances in understanding keloid pathology, there is no effective Food and Drug Administration (FDA)-approved pharmacotherapy. Recent studies have highlighted the possible pathologic role of T helper (Th)17 cells and interleukin (IL)-17 in keloid formation, as well as their implication in other inflammatory disorders. This systematic review characterizes the role of Th17 cells and IL-17 in keloid pathogenesis, highlighting this pathway as a potential therapeutic target. Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive search on PubMed, Embase, MEDLINE, and Web of Science databases on June 5, 2024. The search included terms related to Th17 cells, IL-17, and keloids. Thirteen studies met the inclusion criteria, comprising basic science and bioinformatic studies focusing on Th17 cells and IL-17. Key findings include increased Th17 cell infiltration and IL-17 expression in keloids, IL-17's role in amplifying the inflammatory and fibrotic response via the promotion of IL-6 expression, and IL-17's involvement in upregulating fibrotic markers via SDF-1 and HIF-1α pathways. IL-17 also activates the transforming growth factor beta (TGF-β)/Smad pathway in keloid fibroblasts. Th17 cells and IL-17 significantly contribute to the inflammatory and fibrotic processes in keloid pathogenesis. Therefore, targeting the IL-17 pathway offers a potential new therapeutic target to improve keloid patients' outcomes. Future research could further elucidate the role of Th17 cells and IL-17 in keloid pathogenesis and assess the safety and efficacy of targeting this pathway in human studies.

Ixekizumab Demonstrates Rapid and Consistent Efficacy for Patients with Psoriatic Arthritis, Regardless of Psoriasis Severity

INTRODUCTION

Skin involvement in patients with psoriatic arthritis (PsA) worsens the severity and burden of disease. Ixekizumab (IXE), a selective interleukin (IL)-17A antagonist, was compared to placebo (PBO) in the SPIRIT-P1 (NCT01695239) and SPIRIT-P2 (NCT02349295) studies in patients with PsA and evidence of plaque psoriasis. This post hoc analysis reports musculoskeletal, skin, and nail outcomes through week 24 in patients from SPIRIT-P1 and SPIRIT-P2, stratified by mild, moderate, or psoriasis at baseline.

METHODS

This post hoc analysis pooled patients from SPIRIT-P1 and SPIRIT-P2 who were randomly assigned to PBO or IXE 80 mg every 4 weeks (Q4W) or every 2 weeks (Q2W). Efficacy outcomes were analyzed through week 24 by baseline psoriasis severity, defined by percent body surface area (BSA) affected; mild = BSA < 3%, moderate = 3% ≤ BSA ≤ 10%, severe = BSA > 10%. The primary outcomes assessed were the proportion of patients achieving American College of Rheumatology (ACR)20, ACR50, and ACR70 responses. Secondary outcomes included musculoskeletal, disease activity, skin and nail, and health-related quality-of-life measures.

RESULTS

Similar proportions of patients achieved ACR20/ACR50/ACR70 over time across all severity subgroups and treatment arms. More than one-third of IXE-treated patients achieved ACR20 at week 4, or ACR50 at week 24, with no significant differences according to psoriasis severity at baseline. Disease activity outcomes were similar through week 24 with both IXEQ4W and IXEQ2W, regardless of psoriasis severity at baseline. There were no significant differences over 24 weeks in the proportions of IXE-treated patients with mild, moderate, or severe baseline psoriasis who achieved Minimal Disease Activity (MDA). Across all severity subgroups, IXE demonstrated Psoriasis Area Severity Index 100 response as early as week 4, and approximately one-third of IXE-treated patients achieved total skin clearance at week 24.

CONCLUSION

IXE demonstrated rapid and consistent efficacy in joint, skin, and nail for patients with PsA, regardless of baseline psoriasis severity.

TRIAL REGISTRATION

SPIRIT-P1 (NCT01695239), SPIRIT-P2 (NCT02349295).

Psoriasis and Psoriatic Arthritis-Associated Genes, Cytokines, and Human Leukocyte Antigens

In recent years, research has intensified in exploring the genetic basis of psoriasis (PsO) and psoriatic arthritis (PsA). Genome-wide association studies (GWASs), including tools like ImmunoChip, have significantly deepened our understanding of disease mechanisms by pinpointing risk-associated genetic loci. These efforts have elucidated biological pathways involved in PsO pathogenesis, particularly those related to the innate immune system, antigen presentation, and adaptive immune responses. Specific genetic loci, such as TRAF3IP2, REL, and FBXL19, have been identified as having a significant impact on disease development. Interestingly, different genetic variants at the same locus can predispose individuals to either PsO or PsA (e.g., IL23R and deletion of LCE3B and LCE3C), with some variants being uniquely linked to PsA (like HLA B27 on chromosome 6). This article aims to summarize known and new data on the genetics of PsO and PsA, their associated genes, and the involvement of the HLA system and cytokines.

Prevalence and risk of nonalcoholic fatty liver disease among adult psoriatic patients: A systematic review, meta-analysis, and trial sequential analysis

BACKGROUND

This systematic review and meta-analysis aimed to report the evaluation of the prevalence and risk of nonalcoholic fatty liver disease (NAFLD) among adult psoriatic patients in a systematic review and meta-analysis.

METHODS

A comprehensive search was conducted across 4 databases of PubMed, Scopus, Cochrane Library, and Web of Science to collect relevant studies until November 30, 2023, without any restrictions for finding observational studies. The comprehensive meta-analysis version 3.0 software was used to calculate effect sizes, showing the event rate (ER), odds ratio (OR), and a 95% confidence interval (CI) to evaluate NAFLD risk or prevalence in psoriatic patients and controls or psoriatic patients alone. The quality scoring was performed by 1 author based on the Newcastle-Ottawa Scale tool. Publication bias, meta-regression analysis, and sensitivity analyses were performed. Additionally, Trial Sequential Analysis (TSA) was performed using TSA software.

RESULTS

A total of 581 records were identified among the databases and electronic sources. At last, 41 studies involving 607,781 individuals were included in the meta-analysis. The pooled ER of NAFLD among psoriatic patients was 29.5% (95%CI: 19.6%-41.7%) and I2 = 99.79%. The pooled OR of NAFLD in psoriatic patients compared to controls was 1.685 (95%CI: 1.382-2.055; P < .001) and I2 = 87.96%.

CONCLUSIONS

The study found a significant link between psoriasis and NAFLD, with psoriatic patients having a higher chance of developing NAFLD compared to the controls. The study calls for regular NAFLD screening in psoriatic patients to prevent liver complications.

BASDAI versus ASDAS in evaluating axial involvement in patients with psoriatic arthritis: a pooled analysis of two phase 3 studies

Objective

In the absence of axial psoriatic arthritis (axPsA)-specific tools, the BASDAI and Ankylosing Spondylitis Disease Activity Score (ASDAS) are used to assess axial symptoms in patients with PsA. Here, we assessed the performance of BASDAI and ASDAS in patients with PsA.

Methods

Patients with active PsA in DISCOVER-1 and DISCOVER-2 (ClinicalTrials.gov: NCT03162796 and NCT03158285, respectively) with or without axPsA but with available baseline BASDAI information were analysed; those with investigator-identified axial symptoms and imaging-confirmed sacroiliitis comprised the axPsA cohort. Correlations between BASDAI/ASDAS and clinical variables were assessed with Pearson's coefficient (r). Longitudinal effects of enthesitis (Leeds Enthesitis Index [LEI]), swollen joint count and presence versus absence of axPsA on BASDAI/ASDAS (normalized 0-10 scale) were analysed with mixed models for repeated measures.

Results

At baseline in the axPsA (n = 312) and non-axPsA (n = 124) cohorts, BASDAI scores showed no or weak correlation with swollen joint count (0.18-0.20), tender joint count (0.12-0.29), LEI (-0.04 to 0.24) and physician global assessment (0.35-0.43); moderate correlation with fatigue (both -0.56); and strong correlation with patient global assessment of disease activity (0.62-0.69) and patient-reported pain (0.66-0.70). Similar correlations were observed for ASDAS. Axial involvement versus non-involvement was associated with higher BASDAI scores and ASDAS (all β ≥ 0.5), without differences between instruments; longitudinal associations between swollen joint count (β ≤ 0.06)/LEI (β ≤ 0.19) and BASDAI/ASDAS were clinically unimportant.

Conclusion

BASDAI and ASDAS performed similarly in patients with active PsA and axial involvement, independent of peripheral disease involvement, supporting their performance in assessing axial disease activity.

Trial registration

ClinicalTrials.gov, http://clinicaltrials.gov, NCT03162796 and NCT03158285.

IL-23 past, present, and future: a roadmap to advancing IL-23 science and therapy

Interleukin (IL)-23, an IL-12 cytokine family member, is a hierarchically dominant regulatory cytokine in a cluster of immune-mediated inflammatory diseases (IMIDs), including psoriasis, psoriatic arthritis, and inflammatory bowel disease. We review IL-23 biology, IL-23 signaling in IMIDs, and the effect of IL-23 inhibition in treating these diseases. We propose studies to advance IL-23 biology and unravel differences in response to anti-IL-23 therapy. Experimental evidence generated from these investigations could establish a novel molecular ontology centered around IL-23-driven diseases, improve upon current approaches to treating IMIDs with IL-23 inhibition, and ultimately facilitate optimal identification of patients and, thereby, outcomes.

Serum Beta-Defensin-2 is a biomarker for psoriasis but not subclinical atherosclerosis: Role of IL17a, PI-3 kinase and Rac1

Background

Beta-defensins (BDs) are antimicrobial peptides secreted upon epithelial injury. Both chemotactic and antimicrobial properties of BDs function as initial steps in host defense and prime the adaptive immune system in the body. Psoriasis, a chronic immune-mediated inflammatory disease, has both visible cutaneous manifestations as well as known associations with higher incidence of cardiometabolic complications and vascular inflammation.

Objectives

We aimed to investigate the circulating expression of beta-defensin-2 (BD2) in psoriasis at baseline compared to control subjects, along with changes in BD2 levels following biologic treatment at one-year. The contribution of BD2 to subclinical atherosclerosis is also assessed. In addition, we have sought to unravel signaling mechanisms linking inflammation with BD2 expression.

Methods

Multimodality imaging as well inflammatory biomarker assays were performed in biologic naïve psoriasis (n=71) and non-psoriasis (n=53) subjects. A subset of psoriasis patients were followed for one-year after biological intervention (anti-Tumor Necrosis Factor-α (TNFα), n=30; anti-Interleukin17A (IL17A), n=21). Measurements of circulating BD2 were completed by Enzyme-Linked Immunosorbent Assay (ELISA). Using HaCaT transformed keratinocytes, expression of BD2 upon cytokine treatment was assessed by quantitative polymerase chain reaction (qPCR) and ELISA.

Results

Herein, we confirm that human circulating BD2 levels associate with psoriasis, which attenuate upon biologic interventions (anti-TNFα, anti-IL-17A). A link between circulating BD2 and sub-clinical atherosclerosis markers was not observed. Furthermore, we demonstrate that IL-17A-driven BD2 expression occurs in a Phosphatidylinositol 3-kinase (PI3-kinase) and Rac1 GTPase-dependent manner.

Conclusions

Our findings expand on the potential role of BD2 as a tractable biomarker in psoriasis patients and describes the role of an IL-17A-PI3-kinase/Rac signaling axis in regulating BD2 levels in keratinocytes.

Global trends and research status in ankylosing spondylitis clinical trials: a bibliometric analysis of the last 20 years

BACKGROUND

Ankylosing spondylitis (AS) is a rheumatic and autoimmune disease associated with a chronic inflammatory response, mainly characterized by pain, stiffness, or limited mobility of the spine and sacroiliac joints. Severe symptoms can lead to joint deformity, destruction, and even lifelong disability, causing a serious burden on families and society as a whole. A large number of clinical studies have been published on AS over the past 20 years. This study aimed to summarize the current research status and global trends relating to AS clinical trials through a bibliometric analysis.

METHODS

The Web of Science Core Collection database was searched for publications related to AS clinical trials published between January 2003 and June 2023. Bibliometric analysis and web visualization were performed using CiteSpace, VOSviewer, and a bibliometric online analysis platform (https://bibliometric.com), which included the number of publications, citations, countries, institutions, journals, authors, references, and keywords.

RESULTS

1,212 articles published in 201 journals from 65 countries were included in this study. The number of publications related to AS clinical trials is increasing annually. The United States and the Free University of Berlin, the countries and institutions, respectively, that have published the most articles on AS, have made outstanding contributions to this field. The author with the most published papers and co-citations over the period covered by the study was Desiree Van Der Heijde. The journal with the most published and cited articles was Annals of the Rheumatic Diseases. The keywords: "double-blind," "rheumatoid arthritis," "efficacy," "placebo-controlled trial," "infliximab," "etanercept," "psoriatic arthritis" and "therapy" represent the current research hotspots regarding AS.

DISCUSSION

This is the first study to perform a bibliometric analysis and visualization of AS clinical trial publications, providing a reliable research focus and direction for clinicians. Future studies in the field of AS clinical trials should focus on placebo-controlled trials of targeted therapeutic drugs.

Global trends and research status in ankylosing spondylitis clinical trials: a bibliometric analysis of the last 20 years

Background

Ankylosing spondylitis (AS) is a rheumatic and autoimmune disease associated with a chronic inflammatory response, mainly characterized by pain, stiffness, or limited mobility of the spine and sacroiliac joints. Severe symptoms can lead to joint deformity, destruction, and even lifelong disability, causing a serious burden on families and society as a whole. A large number of clinical studies have been published on AS over the past 20 years. This study aimed to summarize the current research status and global trends relating to AS clinical trials through a bibliometric analysis.

Methods

The Web of Science Core Collection database was searched for publications related to AS clinical trials published between January 2003 and June 2023. Bibliometric analysis and web visualization were performed using CiteSpace, VOSviewer, and a bibliometric online analysis platform (https://bibliometric.com), which included the number of publications, citations, countries, institutions, journals, authors, references, and keywords.

Results

1,212 articles published in 201 journals from 65 countries were included in this study. The number of publications related to AS clinical trials is increasing annually. The United States and the Free University of Berlin, the countries and institutions, respectively, that have published the most articles on AS, have made outstanding contributions to this field. The author with the most published papers and co-citations over the period covered by the study was Desiree Van Der Heijde. The journal with the most published and cited articles was Annals of the Rheumatic Diseases. The keywords: "double-blind," "rheumatoid arthritis," "efficacy," "placebo-controlled trial," "infliximab," "etanercept," "psoriatic arthritis" and "therapy" represent the current research hotspots regarding AS.

Discussion

This is the first study to perform a bibliometric analysis and visualization of AS clinical trial publications, providing a reliable research focus and direction for clinicians. Future studies in the field of AS clinical trials should focus on placebo-controlled trials of targeted therapeutic drugs.

Guselkumab, tildrakizumab, and risankizumab in a real-world setting: drug survival and effectiveness in the treatment of psoriasis and psoriatic arthritis

BACKGROUND

Clinical trials have shown promising results for interleukin-23 inhibitors in the treatment of psoriasis. The drugs have been used in clinical practice since 2017.

OBJECTIVE

To investigate the drug survival and effectiveness of interleukin-23 inhibitors in the treatment of psoriasis and psoriatic arthritis (PsA) in a real-world setting.

METHODS

The study was a retrospective analysis of patients treated with either guselkumab, tildrakizumab, or risankizumab at the Department of Dermatology, Aarhus University Hospital, during the period from June 11 2018, to July 14 2021.

RESULTS

A total of 80 patients were included. During the study, 19 patients discontinued treatment with an interleukin-23 inhibitor, and mean treatment duration (SD) was 61.4 weeks (43.7). Seventy-six patients (95%) had previous use of ≥1 biologic. One-year drug survival was 81.0%. Among patients, 64.3% achieved a Psoriasis Area and Severity Index (PASI) ≤ 2 at weeks 12-17; 61.3%, at weeks 40-60. There was no statistically significant difference between the drugs regarding the chance of achieving PASI ≤ 2 (p>.05). Twenty-two patients (27.5%) had PsA. Among these, 40.9% and 36.4% achieved complete remission and partial remission, respectively.

CONCLUSIONS

Interleukin-23 inhibitors appear to have high and similar drug survival and effectiveness in patients with difficult-to-treat psoriasis and PsA.

Guselkumab Modulates Differentially Expressed Genes in Blood of Patients With Psoriatic Arthritis: Results from Two Phase 3, Randomized, Placebo-Controlled Trials

OBJECTIVE

To evaluate gene expression in blood of patients with psoriatic arthritis (PsA) versus healthy controls and identify changes associated with guselkumab treatment.

METHODS

Whole blood transcriptome profiling via paired-end RNA sequencing was conducted using samples from DISCOVER-1 and DISCOVER-2 at baseline (n = 673) and at weeks 4 and 24 from a representative subgroup that received placebo or guselkumab (n = 227 [longitudinal PsA cohort]). Baseline samples were compared with demographically matched healthy controls (n = 21). Guselkumab-mediated changes in gene expression were assessed in participants from the longitudinal PsA cohort who did versus did not achieve at least 20% improvement in American College of Rheumatology response criteria (ACR20) or at least 75% improvement in Psoriasis Area and Severity Index (PASI75). Differential gene expression was analyzed using edgeR.

RESULTS

At baseline, 355 upregulated and 314 downregulated genes (PsA-associated genes) were identified in patients with PsA versus healthy controls. Upregulated genes were related to neutrophil, mononuclear cell, and CD11b+ gene sets. No cell type-specific gene sets were identified among downregulated genes. Most PsA-associated genes were modulated by guselkumab treatment. At week 24, genes downregulated by guselkumab were enriched with neutrophil, monocyte, eosinophil, and macrophage gene sets; genes upregulated by guselkumab were enriched with B cell, T cell, and natural killer cell gene sets. Reductions in expression of upregulated PsA-associated gene sets were more pronounced in ACR20 and PASI75 responders than in nonresponders.

CONCLUSION

These findings suggest a dysregulation of immune cell profiles in blood from patients in the baseline PsA cohort that approached levels in healthy controls after guselkumab treatment.

Current application status and structure-activity relationship of selective and non-selective JAK inhibitors in diseases

JAK kinase includes four family members: JAK1, JAK2, JAK3, and TYK2. It forms the JAK-STAT pathway with signal transmitters and activators of subscription (STAT). This pathway is one of the main mechanisms by which many cytokine receptors transduce intracellular signals, it is associated with the occurrence of various immune, inflammatory, and tumor diseases. JAK inhibitors block the signal transduction of the JAK-STAT pathway by targeting JAK kinase. Based on whether they target multiple subtypes of JAK kinase, JAK inhibitors are categorized into pan-JAK inhibitors and selective JAK inhibitors. Compared with pan JAK inhibitors, selective JAK inhibitors are associated with a specific member, thus more targeted in therapy, with improved efficacy and reduced side effects. Currently, a number of JAK inhibitors have been approval for disease treatment. This review summarized the current application status of JAK inhibitors that have been marketed, advances of JAK inhibitors currently in phase Ш clinical trials, and the structure-activity relationship of them, with an intention to provide references for the development of novel JAK inhibitors.

Efficacy and safety of IL-23 inhibitors in the treatment of psoriatic arthritis: a meta-analysis based on randomized controlled trials

In recent years, the use of interleukin (IL) 23 inhibitors in the treatment of psoriatic arthritis (PsA) has been the subject of much research. By specifically binding to the p19 subunit of IL-23, IL-23 inhibitors block downstream signaling pathways and inhibit inflammatory responses. The objective of this study was to assess the clinical efficacy and safety of IL-23 inhibitors in the treatment of PsA. PubMed, Web of Science, Cochrane Library, and EMBASE databases were searched from the time of conception to June 2022 for randomized controlled trials (RCTs) investigating the use of IL-23 in PsA therapy. The main outcome of interest was the American College of Rheumatology 20 (ACR20) response rate at week 24. We included six RCTs (3 studies on guselkumab, 2 on risankizumab, and 1 on tildrakizumab) with a total of 2971 PsA patients in our meta-analysis. We found that the IL-23 inhibitor group showed a significantly higher ACR20 response rate compared to the placebo group (relative risk = 1.74, 95% confidence interval: 1.57-1.92; P < 0.001; I2 = 40%). There was no statistical difference in the risk of adverse events (P = 0.07) and serious adverse events (P = 0.20) between the IL-23 inhibitor and placebo groups. Notably, the rate of elevated transaminases in the IL-23 inhibitor group was higher than the placebo group (relative risk = 1.69; 95%CI 1.29-2.23; P < 0.001; I2 = 24%). In the treatment of PsA, IL-23 inhibitors significantly outperform placebo intervention while maintaining a favorable safety profile.

Meta-analysis and GRADE assessment of randomized controlled trials on the efficacy and safety of bimekizumab in psoriatic arthritis patients

OBJECTIVE

A persistent immune-mediated inflammatory disorder called psoriatic arthritis affects about 25% of persons with psoriasis. Bimekizumab, a humanized monoclonal IgG1 antibody, is a novel therapeutic approach that inhibits homodimers and heterodimers of IL-17A and IL-17F by binding to comparable locations in these molecules. Bimekizumab was the subject of a meta-analysis to assess its efficacy and safety in psoriatic arthritis patients.

METHODS

All randomized clinical trials were looked up on PubMed, Scopus, and Web of Science. The Systematic Review Accelerator tool was used to screen them, and RevMan was used to analyze them. The Mean Difference (MD) and 95% Confidence Interval (CI) were used to examine continuous data, whereas the Risk Ratio (RR) and 95% CI were used to evaluate dichotomous data.

RESULTS

A total of 1364 participants from 4 trials were included in this meta-analysis. The number of participants who met the American College of Rheumatology 50 threshold was significantly higher in the bimekizumab group compared to the placebo group [RR = 4.94, 95% CI (3.73, 6.55), p < .00001]. Psoriasis Area and Severity Index 100 was achieved by significantly more people in the bimekizumab group than in the placebo group [RR = 11.45, 95% CI (6.67, 19.67), p < .00001]. There was no significant difference between the bimekizumab group and the placebo group in terms of treatment-emergent adverse events [RR = 1.08, 95% CI (0.97, 1.21), p = .15].

CONCLUSION

In comparison to a placebo, bimekizumab treatment significantly improved joint and skin efficacy outcomes. Also, its safety results were acceptable.

Genetic and Molecular Distinctions Between Axial Psoriatic Arthritis and Radiographic Axial Spondyloarthritis: Post Hoc Analyses from Four Phase 3 Clinical Trials

INTRODUCTION

Emerging evidence suggests psoriatic arthritis (PsA) with axial involvement (axPsA) and radiographic axial spondyloarthritis (r-axSpA) may possibly represent distinct disorders, with some differing clinical manifestations, genetic associations, and radiographic findings. Moreover, axPsA and r-axSpA may respond differently to therapies: guselkumab (interleukin [IL]-23p19 subunit inhibitor [i]) and ustekinumab (IL-12/23p40i) demonstrated improvements in axial symptoms in patients with PsA; however, neither risankizumab (IL-23p19i) nor ustekinumab demonstrated efficacy versus placebo in patients with r-axSpA. Current analyses aim to further understand potential molecular distinctions between axPsA and r-axSpA and examine the pharmacodynamic effects of guselkumab in patients with axPsA and those with PsA without axial involvement (non-axPsA).

METHODS

Post hoc analyses utilized biomarker data from blood and serum samples collected from a subset of participants in phase 3 studies of ustekinumab in r-axSpA and guselkumab in PsA (DISCOVER-1 and DISCOVER-2). Participants with axPsA were identified by investigator-verified sacroiliitis (imaging-confirmed) and axial symptoms. HLA mapping, serum cytokine analysis, and whole-blood RNA sequencing were conducted.

RESULTS

Relative to r-axSpA, patients with axPsA had a lower prevalence of HLA-B27, HLA-C01, and HLA-C02 alleles and a higher prevalence of HLA-B13, HLA-B38, HLA-B57, HLA-C06, and HLA-C12 alleles. Compared with r-axSpA, patients with axPsA had elevated baseline levels of serum IL-17A and IL-17F cytokines, enrichment of IL-17 and IL-10 pathway-associated genes, and neutrophil gene markers. Across axPsA and non-axPsA cohorts, reductions in cytokine levels and normalization of pathway-associated gene expression with guselkumab treatment were comparable.

CONCLUSION

The differences in HLA genetic associations, serum cytokines, and enrichment scores support the concept that axPsA and r-axSpA may be distinct disorders. The comparable pharmacodynamic effects of guselkumab on cytokine levels and pathway-associated genes observed in patients with axPsA and non-axPsA are consistent with demonstrated clinical improvements across PsA cohorts. These findings contribute to the understanding of potential genetic and molecular distinctions between axPsA and r-axSpA.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers, NCT03162796, NCT0315828, NCT02437162, and NCT02438787.

Contact lens-induced corneal parainflammation involving Ly6G+ cell infiltration requires IL-17A and γδ T cells

PURPOSE

Previously, using a murine model, we reported that contact lens (CL) wear induced corneal parainflammation involving CD11c+ cells after 24 h and Ly6G+ cells (neutrophils) after 5-6 days. Here, we investigated the role of IL-17 and γδ T cells in the CL-induced neutrophil response.

METHODS

CL-wearing C57BL/6 wild-type (WT) mice were compared to lens-wearing IL-17A/F single or double gene knock-out mice, or mice treated with UC7-13D5 monoclonal antibody to functionally deplete γδ T cells. Contralateral eyes served as no lens wear controls. Corneal Ly6G+ and γδ T cell responses were quantified as was expression of genes encoding pro-inflammatory cytokines IL-17A/F, IL-β, IL-18 and expression of IL-17A/F protein.

RESULTS

After 6 days lens wear, WT corneas showed Ly6G+ cell infiltration while remaining free of visible pathology. In contrast, lens-wearing corneas of IL-17AF (-/-), IL-17A (-/-) mice and γδ T cell-depleted mice showed little or no Ly6G+ cell infiltration. No Ly6G+ cell infiltration was detected in contralateral eye controls. Lens-wearing WT corneas also showed a significant increase in γδ T cells after 24 h that was maintained after 6 days of wear, and significantly increased cytokine gene expression after 6 days versus contralateral controls: IL-18 & IL-17A (∼3.9 fold) and IL-23 (∼6.5-fold). Increased IL-17A protein (∼4-fold) was detected after 6 days lens wear. γδ T cell-depletion abrogated these lens-induced changes in cytokine gene and protein expression.

CONCLUSION

Together, these data show that IL-17A and γδ T cells are required for Ly6G+ cell (neutrophil) infiltration of the cornea during contact lens-induced parainflammation.

Psoriatic Arthritis: Pathogenesis and Targeted Therapies

Psoriatic arthritis (PsA), a heterogeneous chronic inflammatory immune-mediated disease characterized by musculoskeletal inflammation (arthritis, enthesitis, spondylitis, and dactylitis), generally occurs in patients with psoriasis. PsA is also associated with uveitis and inflammatory bowel disease (Crohn's disease and ulcerative colitis). To capture these manifestations as well as the associated comorbidities, and to recognize their underlining common pathogenesis, the name of psoriatic disease was coined. The pathogenesis of PsA is complex and multifaceted, with an interplay of genetic predisposition, triggering environmental factors, and activation of the innate and adaptive immune system, although autoinflammation has also been implicated. Research has identified several immune-inflammatory pathways defined by cytokines (IL-23/IL-17, TNF), leading to the development of efficacious therapeutic targets. However, heterogeneous responses to these drugs occur in different patients and in the different tissues involved, resulting in a challenge to the global management of the disease. Therefore, more translational research is necessary in order to identify new targets and improve current disease outcomes. Hopefully, this may become a reality through the integration of different omics technologies that allow better understanding of the relevant cellular and molecular players of the different tissues and manifestations of the disease. In this narrative review, we aim to provide an updated overview of the pathophysiology, including the latest findings from multiomics studies, and to describe current targeted therapies.

Multidomain Efficacy and Safety of Guselkumab Through 1 Year in Patients With Active Psoriatic Arthritis With and Without Prior Tumor Necrosis Factor Inhibitor Experience: Analysis of the Phase 3, Randomized, Placebo-Controlled DISCOVER-1 Study

OBJECTIVE

To evaluate efficacy and safety of the interleukin-23p19-subunit inhibitor, guselkumab, in DISCOVER-1 patients with active psoriatic arthritis (PsA) by prior use of tumor necrosis factor inhibitor (TNFi).

METHODS

The phase 3, randomized, placebo-controlled DISCOVER-1 study enrolled patients with active PsA (swollen joint count ≥3, tender joint count ≥3, and C-reactive protein level ≥ 0.3 mg/dl) despite standard therapies; approximately one-third could have received two or fewer prior TNFi. Patients were randomized to 100 mg of guselkumab every 4 weeks (Q4W); 100 mg of guselkumab at week 0, at week 4, and every 8 weeks (Q8W); or placebo with crossover to guselkumab Q4W at week 24. Efficacy end points of ≥20% and ≥50% improvement in individual American College of Rheumatology (ACR) criteria and achieving the minimal disease activity (MDA) components were summarized by prior TNFi status.

RESULTS

In DISCOVER-1, 118 (31%) patients previously received one or two TNFi. As previously reported, rates for acheiving ≥20% improvement in the composite ACR response at week 24 and week 52 were similar in TNFi-naive and TNFi-experienced patients randomized to guselkumab Q4W (76% and 68%, respectively) and Q8W (61% and 58%, respectively). Similar trends were observed for response rates of ≥20% and ≥50% improvement in individual ACR criteria and for achieving individual MDA components at week 24; TNFi-naive patients were more likely to achieve end points related to physical function and pain than TNFi-experienced patients. Overall, response rates were maintained or increased through week 52 regardless of prior TNFi use. Through week 60 in guselkumab-treated TNFi-naive and TNFi-experienced patients, 62% and 64%, respectively, reported one or more adverse events (AEs); 4% and 6% had serious AEs, respectively.

CONCLUSION

Through 1 year, 100 mg of guselkumab Q4W and Q8W provided sustained improvements across multiple domains in both TNFi-naive and TNFi-experienced patients with active PsA.

Axial involvement in psoriatic arthritis

Among the variety of clinical manifestations of psoriatic arthritis (PsA) – including peripheral arthritis, dactylitis, enthesitis, and axial disease – spondylitis is the least studied. There is no generally accepted definition of axial PsA (axPsA), nor is there any common terminology or diagnostic criteria for it. In the rheumatology community, there is also no consensus regarding radiological and MRI assessment of axial involvement in PsA patients, while disease activity indexes and the therapeutic tactics are borrowed from those used in treating axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). However, despite a range of similarities in immunopathogenetic mechanisms of axPsA and axSpA, there are also certain differences that may affect the treatment response in these patients. The aim of this review is the analysis of data on axial disease in PsA. The article discusses the genetic features, clinical presentations, imaging techniques, differential diagnostics and treatment options of axPsA.

Targeting the transcription factor HES1 by L-menthol restores protein phosphatase 6 in keratinocytes in models of psoriasis

Protein Phosphatase 6 down-regulation in keratinocytes is a pivotal event that amplifies the inflammatory circuits in psoriasis, indicating that restoration of protein phosphatase 6 can be a rational strategy for psoriasis treatment. Through the phenotypic screen, we here identify L-menthol that ameliorates psoriasis-like skin inflammation by increasing protein phosphatase 6 in keratinocytes. Target identification approaches reveal an indispensable role for the transcription factor hairy and enhancer of split 1 in governing the protein phosphatase 6-upregulating function of L-menthol in keratinocytes. The transcription factor hairy and enhancer of split 1 is diminished in the epidermis of psoriasis patients and imiquimod-induced mouse model, while L-menthol upregulates the transcription factor hairy and enhancer of split 1 by preventing its proteasomal degradation. Mechanistically, the transcription factor hairy and enhancer of split 1 transcriptionally activates the expression of immunoglobulin-binding protein 1 which promotes protein phosphatase 6 expression and inhibits its ubiquitination. Collectively, we discover a therapeutic compound, L-menthol, for psoriasis, and uncover the dysfunctional the transcription factor hairy and enhancer of split 1- immunoglobulin-binding protein 1- protein phosphatase 6 axis that contributes to psoriasis pathology by using L-menthol as a probe.

SerpinB7 deficiency contributes to development of psoriasis via calcium-mediated keratinocyte differentiation dysfunction

Defective execution of proteases and protease inhibitors that mediate abnormal signaling cascades is emerging as a key contributor to skin diseases, such as psoriasis. SerpinB7 is identified as a skin-specific endogenous protease inhibitor, but the role and underlying mechanism in psoriasis are poorly understood. Here we found that SerpinB7 is highly expressed in psoriatic keratinocytes of patients and imiquimod-induced psoriatic lesions in mice. SerpinB7^-/- mice showed abnormal epidermal barrier integrity and skin architecture in homeostasis, and aggravated psoriatic lesion with inhibiting terminal differentiation and increasing inflammatory cells infiltration compared to SerpinB7^+/+ mice after Imiquimod treatment. Mechanistically, SerpinB7 deficiency results in excessive proliferation and impaired differentiation, as well as increased chemokines and antimicrobial peptide expression in normal human epidermal keratinocyte and mouse primary keratinocyte. Transcriptomics and proteomics results showed that the SeprinB7 deficiency affected keratinocyte differentiation and proinflammatory cytokines, possibly by affecting the calcium ion channel-related proteins. Notably, we demonstrated that SerpinB7 deficiency prevented the increase in intracellular Ca²⁺ influx, which was partly eliminated by the intracellular Ca²⁺ chelator BAPTA-AM. Our findings first described the critical role of SerpinB7 in the regulation of keratinocyte differentiation and psoriatic microenvironment mediated via keratinocytes' intracellular calcium flux, proposing a new candidate for therapeutic targets in psoriasis.

NETosis in Psoriatic Arthritis: Serum MPO–DNA Complex Level Correlates With Its Disease Activity

Background

Neutrophil extracellular trap formation (NETosis) has been rarely reported in psoriatic arthritis (PsA). We aimed to explore the involvement of NETosis in the inflammation of PsA.

Methods

Serum myeloperoxidase–DNA (MPO-DNA) complex was detected by a modified enzyme-linked immunosorbent assay and compared among 74 patients with PsA, 58 patients with psoriasis (PsO), and 20 healthy controls. The association of MPO–DNA level with disease activity index at baseline and follow-up was analyzed in patients with PsA. Receiver operating characteristic curve was used to evaluate the predictive value of MPO–DNA for treatment response.

Results

MPO–DNA complex level in serum was significantly increased in patients with PsA/PsO compared to healthy controls (p &lt; 0.001). The level of MPO–DNA was positively associated with DAPSA score and its components (including TJC, SJC, PGA, VAS-pain and CRP, r = 0.25–0.409, all p-values &lt; 0.05). Serum MPO–DNA level was downregualted at 12 weeks after treatment compared to baseline (p = 0.022). The decrease of MPO–DNA level was more dramatic in patients with PsA who achieved both ACR50 and PASI50 response than those achieving neither of them at 12 weeks (p = 0.023). ROC analysis revealed that the serum MPO–DNA level predicted both ACR50 and PASI50 achievement at week 12 (p = 0.04; 95% CIs, 0.56–0.94). Moreover, the baseline MPO–DNA level (p = 0.009; 95% CIs, 0.748–1) and change of MPO–DNA at week 12 from baseline (p = 0.004; 95% CIs, 0.802–1) were associated with the achievement of both ACR70 and PASI75 response at week 24.

Conclusions

NETosis plays an important role in psoriatic diseases. The level of MPO–DNA complex in serum reflects disease activity. Serum MPO–DNA complex may be a useful biomarker to predict the therapeutic response in PsA.

TRAF3IP2 regulated by FOXO4 affects fibroblast proliferation, migration and extracellular matrix deposition in keloid through the TGF-β1/Smad pathway

BACKGROUND

Keloids are "tumor-like" scars that grow beyond the boundary of injury. Its pathogenesis is complex. This paper will discuss the pathogenesis of keloid from the transcriptional regulation mechanism of TRAF3IP2.

METHODS

IL-17 was utilized to induce human keloid fibroblasts (KFs) and normal dermal fibroblasts. With the application of RT-qPCR and Western blot, TRAF3IP2 expression was detected. . Subsequently, the expression of TRAF3IP2 was interfered by cell transfection and the effects of interfering TRAF3IP2 on cell proliferative rate, migration rate as well as extracellular matrix were assessed with CCK-8, Wound Healing, immunofluorescence as well as Western blot techniques. proliferation, migration and (ECM) deposition were detected by JASPAR software predicted the binding sites of transcription factors FOXO4 and TRAF3IP2 promoters. The relationship between FOXO4 and TRAF3IP2 was verified by Dual luciferase activity assay and ChIP. Finally, the expression of TRAF3IP2 and FOXO4 was interfered simultaneously to further explore the mechanism.

RESULTS

TRAF3IP2 was enhanced in IL-17 induced KFs. Interference with TRAF3IP2 imparted suppressive effects on the proliferation, migration as well as ECM deposition of KFs. FOXO4 could inhibit TRAF3IP2 transcription. And interference with FOXO4 reversed the effect of TRAF3IP2 downregulation on KFs via TGF-β1/Smad pathway.

CONCLUSION

TRAF3IP2 was regulated by FOXO4 and affected fibroblast proliferation, migration and ECM deposition in keloid through the TGF-β1/Smad pathway.

Lipocalin 2 Participates in the Epidermal Differentiation and Inflammatory Processes of Psoriasis

As a multifunctional cytokine, lipocalin 2 is weakly expressed in skin and serum under normal conditions. However, it is over-expressed by neutrophils and keratinocytes in the skin lesions and sera in several skin diseases. Recent studies demonstrated that lipocalin 2 participates in the pathogenesis of psoriasis by exerting versatile effects on skin resident cells and infiltrating immune cells. Lipocalin 2 inhibits the synthesis of keratin, involucrin, and loricrin in keratinocytes, leading to epidermal parakeratosis via the Tcf7l1-lipocalin 2 signaling axis. It also recruits inflammatory cells such as T cells and neutrophils into skin lesions via the IL-23/IL17, p38-MAPK, and ERK-1/2 signaling pathways. Additionally, lipocalin 2 and other cytokines such as IL-17 have the synergetic effects on skin cells. The neutralization of lipocalin 2 or relevant cytokines can alleviate psoriasis, verifying that lipocalin 2 is an effective interfering target for psoriasis. In this review, we summarize the roles of lipocalin 2 in the processes of psoriatic inflammation and the promising therapeutic strategies based on lipocalin 2-related molecules.

Enhanced uptake and anti-maturation effect of celastrol-loaded mannosylated liposomes on dendritic cells for psoriasis treatment

Psoriasis is an autoimmune skin disease in which dendritic cells (DCs) trigger the progression of psoriasis by complex interactions with keratinocytes and other immune cells. In the present study, we aimed to load celastrol, an anti-inflammatory ingredient isolated from Chinese herbs, on mannosylated liposomes to enhance DC uptake as well as to induce DC tolerance in an imiquimod-induced psoriasis-like mouse model. Mannose was grafted onto liposomes to target mannose receptors on DCs. The results demonstrated that compared with unmodified liposomes, DCs preferred to take up more fluorescence-labeled mannosylated liposomes. After loading celastrol into mannose-modified liposomes, they effectively inhibited the expression of maturation markers, including CD80, CD86 and MHC-II, on DCs both in vitro and in vivo. Additionally, after intradermal injection with a microneedle, celastrol-loaded mannose-modified liposomes (CEL-MAN-LPs) achieved a superior therapeutic effect compared with free drug and celastrol-loaded unmodified liposomes in the psoriasis mouse model in terms of the psoriasis area and severity index, histology evaluation, spleen weight, and expression of inflammatory cytokines. In conclusion, our results clearly revealed that CEL-MAN-LPs was an effective formulation for psoriasis treatment and suggested that this treatment has the potential to be applied to other inflammatory diseases triggered by activated DCs.

Interleukin-17 family members in health and disease

The interleukin-17 (IL-17) family consists of six family members (IL-17A-IL-17F) and all the corresponding receptors have been identified recently. This family is mainly involved in the host defense mechanisms against bacteria, fungi and helminth infection by inducing cytokines and chemokines, recruiting neutrophils, inducing anti-microbial proteins and modifying T-helper cell differentiation. IL-17A and some other family cytokines are also involved in the development of psoriasis, psoriatic arthritis and ankylosing spondylitis by inducing inflammatory cytokines and chemokines, and antibodies against IL-17A as well as the receptor IL-17RA are being successfully used for the treatment of these diseases. Involvement in the development of inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis and tumors has also been suggested in animal disease models. In this review, we will briefly review the mechanisms by which IL-17 cytokines are involved in the development of these diseases and discuss possible treatment of inflammatory diseases by targeting IL-17 family members.

Efficacy of guselkumab on axial involvement in patients with active psoriatic arthritis and sacroiliitis: a post-hoc analysis of the phase 3 DISCOVER-1 and DISCOVER-2 studies

BACKGROUND

Guselkumab was efficacious in reducing signs and symptoms of psoriatic arthritis in the phase 3 DISCOVER-1 and DISCOVER-2 studies. We aimed to evaluate the efficacy of guselkumab in post-hoc analyses of patients with psoriatic arthritis with imaging-confirmed sacroiliitis consistent with axial involvement.

METHODS

In DISCOVER-1, 381 patients with active psoriatic arthritis (defined as ≥3 swollen joints, ≥3 tender joints, and C-reactive protein [CRP] ≥0·3 mg/dL) and in DISCOVER-2, 739 patients with active psoriatic arthritis (defined as ≥5 swollen joints, ≥5 tender joints, and CRP ≥0·6 mg/dL) were randomly allocated to receive guselkumab 100 mg every 4 weeks, guselkumab 100 mg every 8 weeks (week 0, week 4, then every 8 weeks), or placebo. These pooled, post-hoc analyses included patients with axial disease documented by previous imaging or pelvic radiography at screening consistent with sacroiliitis (confirmed by investigator). Efficacy assessments included least squares mean changes, with 95% CIs, in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score, modified BASDAI (mBASDAI; excluding peripheral joint pain), spinal pain, and Ankylosing Spondylitis Disease Activity Score (ASDAS), and proportions of patients achieving at least a 50% improvement in BASDAI score (BASDAI50) and achieving ASDAS responses of inactive disease (score <1·3), major improvement (change of ≥2·0), and clinically important improvement (change of ≥1·1).

FINDINGS

Of the 1120 patients in the two DISCOVER studies, 312 (28%) were included in this analysis, of whom 118 were in the placebo group, 103 were in the guselkumab every 4 weeks group, and 91 were in the guselkumab every 8 weeks group. 191 (61%) were male, and 121 (39%) were female, and the mean age was 45·1 (SD 11·2). HLA-B27 status was assessed in 190 patients; 57 (30%) were HLA-B27-positive and 133 (70%) were HLA-B27-negative. At week 24, least squares mean changes from baseline in BASDAI were -2·7 (95% CI -3·2 to -2·2) in both guselkumab groups versus -1·3 (-1·8 to -0·9) in the placebo group; similar results were observed for mBASDAI and spinal pain. Least squares mean changes in ASDAS scores at week 24 were -1·4 (95% CI -1·7 to -1·2) in both guselkumab groups and -0·7 (-0·9 to -0·5) for placebo. At week 24, 36 (38%) patients in the guselkumab every 4 weeks group and 34 (40%) of those in the guselkumab every 8 weeks group achieved BASDAI50 versus 21 (19%) of placebo patients; greater proportions of guselkumab-treated patients achieved ASDAS responses versus placebo. Across outcomes, separation from placebo was observed at week 8. Improvements with guselkumab were seen at week 24 independent of HLA-B27 status. These improvements were maintained at week 52 in the guselkumab groups.

INTERPRETATION

Patients with active psoriatic arthritis and imaging-confirmed sacroiliitis who were treated with guselkumab every 4 weeks or every 8 weeks had greater mean improvements in BASDAI and ASDAS (as early as week 8) than did placebo-treated participants, with sustained improvements at week 52.

FUNDING

Janssen Research & Development LLC.

Phenotype and pathological significance of MCAM+ (CD146+) T cell subset in psoriatic arthritis

Background

CD146 (MCAM-melanoma cell adhesion molecule) is a cell surface adhesion molecule for Laminin 411. T cells expressing MCAM are mainly responsible for IL-17 production. IL-17 secreting T helper cells (Th17 cells) are critical for the pathogenesis of psoriatic arthritis (PsA). Here we hypothesized enrichment of CD146⁺IL-17⁺ memory T cells in PsA synovium and studied the association of CD146 expression and CD4⁺IL-17⁺ activated memory (CD11a⁺CD45RO⁺) T cells in synovial fluid and blood of PSA, rheumatoid arthritis (RA, a positive control) and osteoarthritis (OA) patients.

Methods

Hi-D FACS studies were done to identify IL-17 in CD4⁺CD146⁺CD45RO⁺ and CD8⁺CD146⁺CD45RO⁺ T cells.

Results

We observed that effector CD146⁺(MCAM⁺) T cells are enriched at the synovial inflammation site in PsA.

Conclusion

As CD146⁺ T cells are a key resource for IL-17 it is likely that the enrichment of these MCAM⁺ pathologic cells are critical for the disease process of PsA.

Comparative effectiveness of guselkumab in psoriatic arthritis: results from systematic literature review and network meta-analysis

Objective

The efficacy of the novel interleukin (IL)-23p19 inhibitor guselkumab for psoriatic arthritis (PsA) has recently been demonstrated in two phase 3 trials (DISCOVER-1 & -2) but has not been evaluated vs other targeted therapies for PsA. The objective was to compare guselkumab to targeted therapies for PsA for safety and joint and skin efficacy through network meta-analysis (NMA).

Methods

A systematic literature review was conducted in January 2020 to identify randomized controlled trials. Bayesian NMAs were performed to compare treatments on American College of Rheumatology (ACR) 20/50/70 response, mean change from baseline in van der Heijde-Sharp (vdH-S) score, Psoriasis Area Severity Index (PASI) 75/90/100 response, adverse events (AEs) and serious adverse events (SAEs).

Results

Twenty-six phase 3 studies evaluating 13 targeted therapies for PsA were included. For ACR 20 response, guselkumab 100 mg every 8 weeks (Q8W) was comparable to IL-17A inhibitors and subcutaneous tumor necrosis factor (TNF) inhibitors. Similar findings were observed for ACR 50 and 70. For vdH-S score, guselkumab Q8W was comparable to other agents except intravenous TNF therapies. Results for PASI 75 and PASI 90 response suggested guselkumab Q8W was better than most other agents. For PASI 100, guselkumab Q8W was comparable to other active agents. For AEs and SAEs, guselkumab Q8W ranked highly but comparative conclusions were uncertain. Similar results were observed for all outcomes for guselkumab 100 mg every four weeks.

Conclusions

In this NMA, guselkumab demonstrated favorable arthritis efficacy comparable to IL-17A and subcutaneous TNF inhibitors while offering better PASI response relative to many other treatments.

Clinical, laboratory, and genetic markers for the development or presence of psoriatic arthritis in psoriasis patients: a systematic review

Twenty to thirty percent of psoriasis (Pso) patients will develop psoriatic arthritis (PsA). Detection of Pso patients that are (at risk for) developing PsA is essential to prevent structural damage. We conducted a systematic search of five bibliographic databases, up to May 2020. We searched for studies assessing markers (clinical, laboratory, genetic) associated with the development or presence of PsA in Pso patients. Study selection and quality assessment of the included studies was performed, followed by a qualitative best evidence synthesis to determine the level of evidence for a marker and its association with concomitant/developing PsA in Pso. Overall, 259 possible markers were identified in 119 studies that met the inclusion criteria. Laboratory markers related to inflammation and bone metabolism reached a strong level of evidence for the association (not prediction) of PsA in Pso. Only CXCL10 showed strong evidence for a positive predictive value for PsA in Pso. The importance of timely detecting PsA in a Pso population, and finding more (bio)markers contributing to early detection, remains high.

Impact of guselkumab, an interleukin-23 p19 subunit inhibitor, on enthesitis and dactylitis in patients with moderate to severe psoriatic arthritis: results from a randomised, placebo-controlled, phase II study

Objective

To evaluate the effect of guselkumab on enthesitis and dactylitis in a phase II trial of patients with active psoriatic arthritis (PsA).

Methods

This was a phase II, randomised, placebo-controlled, double-blind trial of adults with active PsA (≥3 swollen and ≥3 tender joints and C reactive protein ≥0.3 mg/dL) despite conventional synthetic disease-modifying anti-rheumatic drug, non-steroidal anti-inflammatory drug, and/or oral corticosteroid therapy. Patients were randomised to subcutaneous injections of guselkumab 100 mg or placebo at weeks 0, 4 and every 8 weeks, with placebo crossover to guselkumab at week 24. Dactylitis was scored on a scale of 0–3 on each digit; enthesitis was assessed using the Leeds Enthesitis Index (0–6). Other assessments included American College of Rheumatology (ACR) and Psoriasis Area and Severity Index responses.

Results

Of 149 randomised patients, 107 patients had enthesitis (mean score=2.7) and 81 patients had dactylitis (mean dactylitis score=5.7) at baseline. Mean improvements in enthesitis and dactylitis at week 24 were greater in the guselkumab group versus placebo and sustained through week 56. Similar results were observed for the proportions of patients with resolution of enthesitis and dactylitis. At week 56, mean improvements in enthesitis and dactylitis among patients who switched from placebo to guselkumab treatment were similar to those in the guselkumab group. In the guselkumab group, ACR20 responders had greater improvements in enthesitis and dactylitis versus non-responders (week 24).

Conclusions

At week 24, the guselkumab group had greater mean improvements in enthesitis and dactylitis and greater proportions of patients with resolution of enthesitis and dactylitis versus placebo. ACR20 response was associated with improvements in enthesitis and dactylitis.

Trial registration number

ClinicalTrials.gov: NCT02319759.

URL: https://clinicaltrials.gov/ct2/show/NCT02319759; Registered 18 December 2014.

JAK inhibitors, psoriatic arthritis, and axial spondyloarthritis: a critical review of clinical trials

INTRODUCTION

Psoriatic arthritis (PsA) and spondyloarthritis (SpA) are inflammatory arthritides associated with progressive damage, deformity and morbidity. Janus kinase (JAK) inhibitors block JAKs, cytoplasmic protein tyrosine kinases important in signal transduction and immune processes that are currently being studied as synthetic disease modifying anti-rheumatic drugs (tsDMARDs) in psoriatic arthritis and spondyloarthritis.

AREAS COVERED

This review evaluates published phase 2 and 3 clinical trial data for JAK kinase inhibitors for psoriatic arthritis and spondyloarthritis. A literature search using PubMed was conducted using the following keywords: 'psoriatic arthritis', 'ankylosing spondylitis', 'axial spondyloarthritis', 'non-radiographic axial spondyloarthritis', 'tofacitinib', 'baricitinib', 'filgotinib' and 'upadacitinib'. Mechanism of action, phase 2 and 3 clinical trial data, including efficacy and safety, are discussed.

EXPERT OPINION

JAK inhibitors are important orally administered agents conferring different degrees of selectivity toward JAK1, JAK2, and JAK3 which may have implications on efficacy and safety in PsA and SpA. Phase 2 and 3 clinical trials in PsA for tofacitinib and upadacitinib and phase 2 for filgotinib confirmed efficacy comparable to biologic DMARDs. In SpA, phase 2 and 2/3 studies confirmed significant efficacy of tofacitinib, filgotinib and upadacitinib compared to placebo. Safety was comparable to clinical trial, long-term extension, and registry data for rheumatoid arthritis.

Increased Circulatory Interleukin-17A Levels in Patients with Progressive and Leukotrichial Vitiligo

Background

Vitiligo is a chronic condition characterized by skin depigmentation. Although not life-threatening, it significantly impacts quality of life. The pathophysiology of vitiligo remains poorly understood, and treatment options are limited. Mounting evidence supports the importance of autoreactive T cells and, particularly interleukin-17A- (IL-17A-) secreting Th17 cells, in vitiligo. IL-17A targeting has been proven successful in various inflammatory dermatological conditions, including psoriasis and lupus erythematosus.

Objective

We evaluated the relationship between serum levels of IL-17A and the clinicopathological characteristics of Vietnamese vitiligo patients.

Methods

In this cross-sectional study, we analyzed data from 52 nonsegmental vitiligo patients and 50 age- and sex-matched healthy individuals. Serum levels of IL-17A were measured using an enzyme-linked immunosorbent assay. We evaluated the correlation between IL-17A levels and clinical characteristics including leukotrichia, disease duration, vitiligo activity, and body surface area involvement.

Results

Patients with progressive vitiligo had significantly higher IL-17A levels than patients with stable vitiligo (P = 0.014) or healthy individuals (P = 0.002). In addition, serum IL-17A levels were higher in vitiligo patients with leukotrichia than in patients without it (P = 0.04). Furthermore, serum IL-17A levels were negatively correlated with age (r = -0.39, P = 0.004) and age of onset (r = -0.33, P = 0.016) in vitiligo patients.

Conclusions

Higher serum levels of IL-17A in patients with progressive vitiligo and leukotrichia suggest a potential role of IL-17A in melanocyte destruction in the epidermis and the follicular matrix.

Interleukin-17 and Interleukin-23: A Narrative Review of Mechanisms of Action in Psoriasis and Associated Comorbidities

Psoriasis is an immune-mediated inflammatory skin disease associated with numerous inflammatory comorbidities, including increased cardiovascular risk. The interleukin (IL)-23/IL-17 axis plays a central role in the immunopathogenesis of psoriasis and related comorbidities by acting to stimulate keratinocyte hyperproliferation and feed-forwarding circuits of perpetual T cell-mediated inflammation. IL-17 plays an important role in the downstream portion of the psoriatic inflammatory cascade. This review discusses the distinct mechanisms of action of IL-17 and IL-23 in the immunopathogenesis of psoriasis and related comorbidities plus the significant therapeutic benefits of selectively inhibiting these cytokines in patients with moderate to severe plaque psoriasis.

Efficacy and Safety of Guselkumab, an Interleukin-23p19-Specific Monoclonal Antibody, Through One Year in Biologic-Naive Patients With Psoriatic Arthritis

Objective

Guselkumab, a human monoclonal antibody specific to interleukin‐23p19, demonstrated efficacy and safety versus placebo through week 24 of the phase III DISCOVER‐2 trial in biologic‐naive patients with psoriatic arthritis (PsA). Here we report 1‐year DISCOVER‐2 findings.

Methods

Adults with active PsA (≥5 swollen and ≥5 tender joints; C‐reactive protein level ≥0.6 mg/dl) despite standard nonbiologic treatment were randomized to receive subcutaneous injections of guselkumab 100 mg every 4 weeks, guselkumab 100 mg at week 0, week 4 and every 8 weeks thereafter, or placebo with crossover to guselkumab 100 mg every 4 weeks at week 24. We primarily evaluated clinical efficacy through week 52 by imputing missing data (nonresponse for categorical end points; no change/using multiple imputation for continuous end points). Observed radiographic scores and adverse events (AEs) were summarized.

Results

Of 739 randomized, treated patients, 93% completed week 52. The proportions of patients in whom a ≥20% improvement from baseline in American College of Rheumatology criteria (ACR20) was achieved were maintained after week 24, reaching 71% (173 of 245) and 75% (185 of 248) for patients randomized to receive treatment every 4 weeks or every 8 weeks, respectively, by week 52. The proportions of patients in whom ACR50/ACR70 and skin responses, minimal or very low disease activity, and dactylitis or enthesitis resolution were achieved at week 24 were also maintained through week 52. Further, low levels of radiographic progression, along with improvements in physical function and health‐related quality of life, were sustained through week 52 with continued guselkumab treatment. Few patients experienced serious infections through week 52, with no evidence of a dosing regimen response or increase from weeks 0–24 (4 of 493 [0.8%]) to weeks 24–52 (3 of 493 [0.6%]) among guselkumab‐randomized patients. No patient developed an opportunistic infection or died.

Conclusion

In biologic‐naive PsA patients, guselkumab provided sustained improvements across diverse manifestations and maintained a favorable risk–benefit profile through week 52.

Role of subnetworks mediated by [Formula: see text], IL-23/IL-17 and IL-15 in a network involved in the pathogenesis of psoriasis

Psoriasis is a chronic inflammatory skin disease clinically characterized by the appearance of red colored, well-demarcated plaques with thickened skin and with silvery scales. Recent studies have established the involvement of a complex signalling network of interactions between cytokines, immune cells and skin cells called keratinocytes. Keratinocytes form the cells of the outermost layer of the skin (epidermis). Visible plaques in psoriasis are developed due to the fast proliferation and unusual differentiation of keratinocyte cells. Despite that, the exact mechanism of the appearance of these plaques in the cytokine-immune cell network is not clear. A mathematical model embodying interactions between key immune cells believed to be involved in psoriasis, keratinocytes and relevant cytokines has been developed. The complex network formed of these interactions poses several challenges. Here, we choose to study subnetworks of this complex network and initially focus on interactions involving [Formula: see text], IL-23/IL-17, and IL-15. These are chosen based on known evidence of their therapeutic efficacy. In addition, we explore the role of IL-15 in the pathogenesis of psoriasis and its potential as a future drug target for a novel treatment option. We perform steady state analyses for these subnetworks and demonstrate that the interactions between cells, driven by cytokines could cause the emergence of a psoriasis state (hyper-proliferation of keratinocytes) when levels of [Formula: see text], IL-23/IL-17 or IL-15 are increased. The model results explain and support the clinical potentiality of anti-cytokine treatments. Interestingly, our results suggest different dynamic scenarios underpin the pathogenesis of psoriasis, depending upon the dominant cytokines of subnetworks. We observed that the increase in the level of IL-23/IL-17 and IL-15 could lead to psoriasis via a bistable route, whereas an increase in the level of [Formula: see text] would lead to a monotonic and gradual disease progression. Further, we demonstrate how this insight, bistability, could be exploited to improve the current therapies and develop novel treatment strategies for psoriasis.

Efficacy and safety of interleukin-17A inhibitors in patients with ankylosing spondylitis: a systematic review and meta-analysis of randomized controlled trials

To assess the efficacy and safety of interleukin (IL)-17A inhibitors in patients with ankylosing spondylitis (AS). PubMed, EMBASE, and Web of Science were searched up to 5 February 2020 for randomized controlled trials (RCTs) that assessed the efficacy and safety of IL-17A inhibitors in patients with AS. We used a meta-analytic approach to perform a random effects analysis or fixed effects analysis according to heterogeneity. Subgroup analyses between studies included medication, time to primary endpoint, and data source. Odds ratios (ORs) or mean differences (MDs) were used to assess the efficacy and safety of IL-17A inhibitors in AS. A total of ten RCTs with 2613 patients were eligible for inclusion in the analysis (six for secukinumab, two for ixekizumab, one for netakimab, and one for bimekizumab). Compared to placebo, IL-17A inhibitors improved ASAS20 response rate (OR = 2.58; p < 0.01) and ASAS40 response rate (OR = 2.80; p < 0.01), and significantly increased the risk of AEs (OR = 1.23; p = 0.03) and nasopharyngitis (OR = 1.72; p < 0.01), but not SAEs (OR = 0.87; p = 0.60). IL-17A inhibitors demonstrated better efficacy in patients with AS in several evaluation indicators. However, the safety of IL-17A inhibitors remains to be further studied in studies with larger sample size and longer follow-up times.

The IL-17/IL-23 Axis and Its Genetic Contribution to Psoriatic Arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory disease belonging to the family of spondyloarthropathies (SpA). PsA commonly aggravates psoriasis of the skin and frequently manifests as an oligoarthritis with axial skeletal involvement and extraarticular manifestations including dactylitis, enthesitis, and uveitis. The weight of genetic predisposition to psoriasis and PsA is illustrated by the concordance rates in monozygotic twins which clearly demonstrate that genomics is insufficient to induce the clinical phenotype. The association of PsA with several single nucleotide polymorphisms (SNPs) at the IL23R locus and the involvement of Th17 cells in the immunopathogenesis of PsA clearly put the IL-23/IL-17 axis in the spotlight. The IL-23 and IL-17 cytokines have a pivotal role in the chronic inflammation of the synovium in PsA and are also prominent in the skin lesions of those with PsA. In this review, we focus on the genetic association of the IL-23/IL-17 axis with PsA and the contribution of these master cytokines in the pathophysiology of the disease, highlighting the main cell types incriminated in PsA and their specific role in the peripheral blood, lesional skin and joints of patients. We then provide an overview of the approved biologic drugs targeting the IL-23/IL-17 axis and discuss the advantages of genetic stratification to enhance personalized therapies in PsA.

Targeted Treatment for Erythrodermic Psoriasis: Rationale and Recent Advances

Erythrodermic psoriasis (EP) is an extreme and often refractory variant of psoriasis with high morbidity and increased mortality, and is frequently classified as a dermatological emergency. The pathophysiology of EP is largely unknown but is thought to differ from that of plaque psoriasis. Treatment of EP is challenging, and usually based on clinical experience and patient co-morbidities, due to its low incidence and limited clinical evidence. Conventional treatments, such as topical glucocorticoid therapy, cyclosporin, acitretin, and methotrexate have some but limited efficacy in EP, and treatment discontinuation may result in flares. Newer biological drugs, including anti-TNF, anti-IL-17, and anti-IL-12/23 agents, have shown promise in therapeutic management of EP, but most of the available evidence is currently based on small case series and reports. Few studies have compared available treatment options for EP, and further clinical studies are necessary to provide clinical data and optimal treatment guidelines for EP patients. Here, we provide a comprehensive review of the background of EP, assess the available clinical data on the efficacy of targeted therapies, and aim to provide a foundation for clinical decision making for this rare form of psoriasis.

Differential Requirement for CCR6 in IL-23-Mediated Skin and Joint Inflammation

CCR6 is important for the trafficking of IL-17A-producing γδ T cells and required for the development of psoriasiform dermatitis in an IL-23 intradermal injection model. The role of CCR6, however, in IL-23-mediated joint inflammation is unclear. We herein hydrodynamically delivered IL-23 minicircle DNA into wild-type and CCR6-deficient (CCR6-knockout) mice to induce overexpression of IL-23 systemically. After IL-23 gene transfer, wild-type mice exhibited concurrent skin and joint changes that recapitulate some features found in human psoriatic skin and joints. CCR6-knockout mice were resistant to IL-23-induced skin inflammation but exhibited no changes in joint inflammation compared with wild-type mice. Depletion of neutrophils protected wild-type mice from skin and joint disease without suppressing T helper type 17 cytokine expression. In contrast, mice lacking γδ T cells showed a partial reduction in neutrophilic recruitment and a significant decrease in IL-17A expression in skin and paw tissue. Thus, in an IL-23-mediated model that allows concurrent assessment of both skin and joint disease, we showed that CCR6 is critical for inflammation in the skin but not in the joint. Furthermore, our data suggest that neutrophils and γδ T cells are key effector cells in IL-23-mediated skin and joint inflammation in mice.

IL-23/IL-17 Axis in Inflammatory Rheumatic Diseases

In inflammatory rheumatic disorders, the immune system attacks and damages the connective tissues and invariably internal organs. During the past decade, remarkable advances having been made towards our understanding on the cellular and molecular mechanisms involved in rheumatic diseases. The discovery of IL-23/IL-17 axis and the delineation of its important role in the inflammation led to the introduction of many needed new therapeutic tools. We will present an overview of the rationale for targeting therapeutically the IL-23/IL-17 axis in rheumatic diseases and the clinical benefit which has been realized so far. Finally, we will discuss the complex interrelationship between IL-23 and IL-17 and the possible uncoupling in certain disease settings.