Treatment Outcomes of IL-17 Inhibitors in Hidradenitis Suppurativa: A Systematic Review

Cytokine-Mediated Molecular Pathophysiology of Hidradenitis Suppurativa: A Narrative Review

Background

Hidradenitis suppurativa (HS) is a chronic inflammatory condition of the skin that mainly affects the apocrine gland-rich intertriginous areas. The disease manifests as painful nodules, abscesses, and pus-filled tunnels, which can severely impact patient's quality of life. While diagnosis is clinical, successful treatment options for this condition are limited. There has been an increase in research and clinical trials focusing on biomarkers and cytokines for clinical use. Understanding the potential biomarkers and cytokines implicated in HS pathogenesis may allow efficacious and safe treatment options.

Summary

A literature review was conducted on nine biomarkers and cytokines. IL-1, IL-10, IL-17, IL-23, TNF-α, YKL-40, G-CSF, NOD2, and the complement system were identified due to their potential clinical utilization and pathophysiological involvement in HS.

Key Messages

With further research expanding our understanding of the pathophysiology of HS and the roles these cytokines and biomarkers play, there is potential for utilization as diagnostic markers or development of antagonists against these specific agents for HS management.

Biologics for Hidradenitis suppurativa: evolution of the treatment paradigm

INTRODUCTION

Hidradenitis suppurativa (HS) is an autoinflammatory skin disease with a high unmet need for effective medical management. Clinically, it is characterized by inflammatory nodules that may progress into abscesses, draining tunnels and extensive scarring, mainly affecting apocrine gland-bearing areas.

AREAS COVERED

Treatment options include topical and systemic medications and a variety of surgical procedures. The anti-TNF-α antibody adalimumab and the anti-IL-17 secukinumab are the only two approved biologics for HS, showing moderate efficacy. HS research is a rapidly growing field, with a wide range of agents leveraging distinct mechanisms of action currently under development. Drugs targeting the IL-17 and Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathways are the most advanced in both ongoing and completed Phase 3 studies, promising deeper levels of response. Use of other, off-label biologics is also discussed.

EXPERT OPINION

A therapeutic algorithm is proposed based on comorbidities and existing evidence. Patient-tailored combinations between biologics and other biologics or small molecules will hopefully allow clinicians to target most events in HS pathophysiology in a complementary way while obtaining a meaningful effect on their devastating manifestations.

Brodalumab for severe hidradenitis suppurativa: a case of clinico-radiologic improvement and literature review

Hidradenitis suppurativa (HS) is a chronic autoinflammatory follicular disease, affecting body areas that are rich in apocrine glands. Moderate-to-severe HS may severely impair patients' quality of life also because the available therapies are often unsatisfactory. Several lines of evidence suggest that inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-17 play a pivotal role in the physiopathology of HS. TNF-α inhibitors have long been used with benefit in moderate-severe forms of HS. However, several monoclonal antibodies against IL-17 isoforms are currently being investigated for HS. We report the case of a 50-year-old man with long-standing HS and concomitant palmo-plantar psoriasis treated with brodalumab after failure of various TNF-α inhibitors. The HS lesions and the patient's quality of life improved steadily over time until week-136. Interestingly, the clinical benefit was confirmed by radiological improvement with MRI evaluation. Our case report demonstrates the long-term efficacy and safety of brodalumab in HS encouraging the use of drugs to inhibit the T helper-type 17 immune axis, especially in cases of HS refractory to therapy with TNF-α inhibitors.

NK and NKT cells in the pathogenesis of Hidradenitis suppurativa: Novel therapeutic strategy through targeting of CD2

Hidradenitis suppurativa (HS) is a chronic debilitating inflammatory skin disease with poorly understood pathogenesis. Single-cell RNAseq analysis of HS lesional and healthy individual skins revealed that NKT and NK cell populations were greatly expanded in HS, and they expressed elevated CD2, an activation receptor. Immunohistochemistry analyses confirmed significantly expanded numbers of CD2+ cells distributed throughout HS lesional tissue, and many co-expressed the NK marker, CD56. While CD4+ T cells were expanded in HS, CD8 T cells were rare. CD20+ B cells in HS were localized within tertiary follicle like structures. Immunofluorescence microscopy showed that NK cells (CD2 + CD56 dim ) expressing perforin, granzymes A and B were enriched within the hyperplastic follicular epidermis and tunnels of HS and juxtaposed with apoptotic cells. In contrast, NKT cells (CD2 + CD3 + CD56 bright ) primarily expressed granzyme A and were associated with α-SMA expressing fibroblasts within the fibrotic regions of the hypodermis. Keratinocytes and fibroblasts expressed high levels of CD58 (CD2 ligand) and they interacted with CD2 expressing NKT and NK cells. The NKT/NK maturation and activating cytokines, IL-12, IL-15 and IL-18, were significantly elevated in HS. Inhibition of cognate CD2-CD58 interaction with blocking anti-CD2 mAb in HS skin organotypic cultures resulted in a profound reduction of the inflammatory gene signature and secretion of inflammatory cytokines and chemokines in the culture supernate. In summary, we show that a cellular network of heterogenous NKT and NK cell populations drives inflammation, tunnel formation and fibrosis in the pathogenesis of HS. Furthermore, CD2 blockade is a viable immunotherapeutic approach for the management of HS.

Hidradenitis Suppurativa in Children and Adolescents: An Update on Pharmacologic Treatment Options

Hidradenitis suppurativa (HS) is a chronic, recurrent, inflammatory skin condition that manifests as painful, deep-seated, inflamed nodules and abscesses in the axillary, groin, perianal, perineal, and inframammary regions. The associated pain, malodour, and disfigurement contribute to its profound negative impact on psychosocial spheres and overall quality of life in affected individuals. Although the symptoms of HS classically begin in the second or third decade of life, HS affects children and adolescents as well. Despite this, there are limited pediatric data on treatment, which are largely based on expert opinion, extrapolation of efficacy data in adults with HS, and safety information from medication use in other pediatric diseases. On this basis, there exist several pharmacological modalities in the treatment of children and adolescents with HS including topical therapies, systemic therapies, and biologics. The goals of this review article are to: (1) review the efficacy of different pharmacological treatment modalities in children and adolescents with HS, and (2) review the safety and monitoring considerations of the different treatment options in children and adolescents with HS.

Is Exploration of Alternate Immune Pathways Needed in Hidradenitis Suppurativa? A Case of Atopic Dermatitis and Concurrent Hidradenitis Suppurativa Responding to Dupilumab

Hidradenitis suppurativa (HS) is an inflammatory dermatosis associated with overactive T helper 1/T helper 17 (Th1/Th17) cells. HS has been effectively treated with biologic medications; however, many such biologics lack large randomized controlled trials. Only one such biologic, adalimumab, has been approved by the US Food and Drug Administration (FDA) for the treatment of HS. Other such biologics currently being studied for HS downregulate Th1/Th17 inflammatory pathways. We describe a patient with atopic dermatitis (AD) and comorbid HS, both of which improved several months into treatment with dupilumab. Interestingly enough, dupilumab targets Th2-mediated inflammatory skin conditions through the inhibition of IL-4/IL-13 cytokines. While dupilumab is known for its success in treating Th2-mediated inflammation, this presents a paradox as HS is a Th1/Th17 inflammatory condition. This case highlights how the inflammatory process of HS is not fully understood and how biologic pharmacologic interventions need to be further studied to determine their efficacy in treating HS.

The IL-17 family in diseases: from bench to bedside

The interleukin-17 (IL-17) family comprises six members (IL-17A-17F), and recently, all of its related receptors have been discovered. IL-17 was first discovered approximately 30 years ago. Members of this family have various biological functions, including driving an inflammatory cascade during infections and autoimmune diseases, as well as boosting protective immunity against various pathogens. IL-17 is a highly versatile proinflammatory cytokine necessary for vital processes including host immune defenses, tissue repair, inflammatory disease pathogenesis, and cancer progression. However, how IL-17 performs these functions remains controversial. The multifunctional properties of IL-17 have attracted research interest, and emerging data have gradually improved our understanding of the IL-17 signaling pathway. However, a comprehensive review is required to understand its role in both host defense functions and pathogenesis in the body. This review can aid researchers in better understanding the mechanisms underlying IL-17's roles in vivo and provide a theoretical basis for future studies aiming to regulate IL-17 expression and function. This review discusses recent progress in understanding the IL-17 signaling pathway and its physiological roles. In addition, we present the mechanism underlying IL-17's role in various pathologies, particularly, in IL-17-induced systemic lupus erythematosus and IL-17-related tumor cell transformation and metastasis. In addition, we have briefly discussed promising developments in the diagnosis and treatment of autoimmune diseases and tumors.

Genetic Variants Associated With Hidradenitis Suppurativa

Importance

Hidradenitis suppurativa (HS) is a common and severely morbid chronic inflammatory skin disease that is reported to be highly heritable. However, the genetic understanding of HS is insufficient, and limited genome-wide association studies (GWASs) have been performed for HS, which have not identified significant risk loci.

Objective

To identify genetic variants associated with HS and to shed light on the underlying genes and genetic mechanisms.

Design, Setting, and Participants

This genetic association study recruited 753 patients with HS in the HS Program for Research and Care Excellence (HS ProCARE) at the University of North Carolina Department of Dermatology from August 2018 to July 2021. A GWAS was performed for 720 patients (after quality control) with controls from the Add Health study and then meta-analyzed with 2 large biobanks, UK Biobank (247 cases) and FinnGen (673 cases). Variants at 3 loci were tested for replication in the BioVU biobank (290 cases). Data analysis was performed from September 2021 to December 2022.

Main Outcomes and Measures

Main outcome measures are loci identified, with association of P < 1 × 10-8 considered significant.

Results

A total of 753 patients were recruited, with 720 included in the analysis. Mean (SD) age at symptom onset was 20.3 (10.57) years and at enrollment was 35.3 (13.52) years; 360 (50.0%) patients were Black, and 575 (79.7%) were female. In a meta-analysis of the 4 studies, 2 HS-associated loci were identified and replicated, with lead variants rs10512572 (P = 2.3 × 10-11) and rs17090189 (P = 2.1 × 10-8) near the SOX9 and KLF5 genes, respectively. Variants at these loci are located in enhancer regulatory elements detected in skin tissue.

Conclusions and Relevance

In this genetic association study, common variants associated with HS located near the SOX9 and KLF5 genes were associated with risk of HS. These or other nearby genes may be associated with genetic risk of disease and the development of clinical features, such as cysts, comedones, and inflammatory tunnels, that are unique to HS. New insights into disease pathogenesis related to these genes may help predict disease progression and novel treatment approaches in the future.

The Interleukine-17 Cytokine Family: Role in Development and Progression of Spondyloarthritis, Current and Potential Therapeutic Inhibitors

Spondyloarthritis (SpA) encompasses a group of chronic inflammatory rheumatic diseases with a predilection for the spinal and sacroiliac joints, which include axial spondyloarthritis, psoriatic arthritis, reactive arthritis, arthritis associated with chronic inflammatory bowel disease, and undifferentiated spondyloarthritis. The prevalence of SpA in the population varies from 0.5 to 2%, most commonly affecting young people. Spondyloarthritis pathogenesis is related to the hyperproduction of proinflammatory cytokines (TNFα, IL-17A, IL-23, etc.). IL-17A plays a key role in the pathogenesis of spondyloarthritis (inflammation maintenance, syndesmophites formation and radiographic progression, enthesites and anterior uveitis development, etc.). Targeted anti-IL17 therapies have established themselves as the most efficient therapies in SpA treatment. The present review summarizes literature data on the role of the IL-17 family in the pathogenesis of SpA and analyzes existing therapeutic strategies for IL-17 suppression with monoclonal antibodies and Janus kinase inhibitors. We also consider alternative targeted strategies, such as the use of other small-molecule inhibitors, therapeutic nucleic acids, or affibodies. We discuss advantages and pitfalls of these approaches and the future prospects of each method.

Short-Term Effectiveness, Safety, and Potential Predictors of Response of Secukinumab in Patients with Severe Hidradenitis Suppurativa Refractory to Biologic Therapy: A Multicenter Observational Retrospective Study

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. Biologic drugs have a key role in the long-term anti-inflammatory treatment of moderate to severe patients due to their immunomodulatory properties. The aim of this study is to evaluate the effectiveness and safety of secukinumab in patients with moderate to severe HS after 16 weeks of treatment, and to explore potential predictors of clinical response to the drug.

METHODS

Multicenter observational retrospective study. Patients treated with secukinumab 300 mg every 2 or 4 weeks who had completed at least 16 weeks of follow-up from nine hospitals based in southern Spain (Andalusia) were included in this study. Treatment effectiveness was assessed using the Hidradenitis Suppurativa Clinical Response (HiSCR). Information about adverse events was collected, the therapeutic burden of the patients was calculated as the summation of systemic medical treatments and surgical interventions (excluding incision and drainage) experienced until the start of secukinumab treatment.

RESULTS

Forty-seven patients with severe HS were included for analysis. At week 16, 48.9% (23/47) of patients achieved HiSCR. Adverse events were present in 6.4% (3/47) of the patients. The multivariate analysis showed that female sex and, to a lesser extent, lower body mass index (BMI) and a lower therapeutic burden were potentially associated with a higher probability of HiSCR achievement.

CONCLUSIONS

Favorable short-term effectiveness and safety of secukinumab in the treatment of severe HS patients were observed. Female sex, lower BMI and a lower therapeutic burden may be associated with a higher probability of achieving HiSCR.

Dysregulated CD38 expression in blood and skin immune cells of patients with hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a multifactorial, inflammatory skin disease. Increased systemic inflammatory comorbidities and serum cytokines highlight systemic inflammation as a feature of HS. However, the specific immune cell subsets contributing to systemic and cutaneous inflammation have not been resolved. Here, we generated whole-blood immunomes by mass cytometry. We performed a meta-analysis of RNA-seq data, immunohistochemistry, and imaging mass cytometry to characterize the immunological landscape of skin lesions and perilesions from patients with HS. Blood from patients with HS exhibited lower frequencies of natural killer cells, dendritic cells, and classical (CD14+CD16-) and nonclassical (CD14-CD16+) monocytes, as well as higher frequencies of Th17 cells and intermediate (CD14+CD16+) monocytes than blood from healthy controls. Classical and intermediate monocytes from patients with HS had increased expression of skin-homing chemokine receptors. Furthermore, we identified a CD38+ intermediate monocyte subpopulation that was more abundant in the immunome of blood from patients with HS. Meta-analysis of RNA-seq data found higher CD38 expression in lesional HS skin than in perilesional skin, and markers of classical monocyte infiltration. Imaging mass cytometry showed that CD38+ classical monocytes and CD38+ monocyte-derived macrophages were more abundant in lesional HS skin. Overall, we report targeting CD38 may be worth pursuing in clinical trials.

Dysregulated CD38 expression in blood and skin immune cells of patients with hidradenitis suppurativa

Background

Hidradenitis suppurativa (HS) is a multifactorial, inflammatory skin disease. Increased systemic inflammatory comorbidities and serum cytokines highlight systemic inflammation as a feature of HS. However, the specific immune cell subsets contributing to systemic and cutaneous inflammation have not been resolved.

Objective

Identify features of peripheral and cutaneous immune dysregulation.

Methods

Here, we generated whole-blood immunomes by mass cytometry. We performed a meta-analysis of RNA-seq data, immunohistochemistry, and imaging mass cytometry to characterize the immunological landscape of skin lesions and perilesions from patients with HS.

Results

Blood from patients with HS exhibited lower frequencies of natural killer cells, dendritic cells, and classical (CD14+CD16-) and nonclassical (CD14-CD16+) monocytes, as well as higher frequencies of Th17 cells and intermediate (CD14+CD16+) monocytes than blood from healthy controls. Classical and intermediate monocytes from patients with HS had increased expression of skin-homing chemokine receptors. Furthermore, we identified a CD38+ intermediate monocyte subpopulation that was more abundant in the immunome of blood from patients with HS. Meta-analysis of RNA-seq data found higher CD38 expression in lesional HS skin than in perilesional skin, and markers of classical monocyte infiltration. Imaging mass cytometry showed that CD38+ classical monocytes and CD38+ monocyte-derived macrophages were more abundant in lesional HS skin.

Conclusion

Overall, we report targeting CD38 may be worth pursuing in clinical trials.

Key Messages

3.Monocyte subsets express markers of activation in circulation and HS lesionsTargeting CD38 may be a viable strategy for treating systemic and cutaneous inflammation in patients with HS.

Capsule Summary

4.Dysregulated immune cells in patients with HS express CD38 and may be targeting by anti-CD38 immunotherapy.

IL-17 and IL-17-producing cells in protection versus pathology

IL-17 cytokine family members have diverse biological functions, promoting protective immunity against many pathogens but also driving inflammatory pathology during infection and autoimmunity. IL-17A and IL-17F are produced by CD4⁺ and CD8⁺ T cells, γδ T cells, and various innate immune cell populations in response to IL-1β and IL-23, and they mediate protective immunity against fungi and bacteria by promoting neutrophil recruitment, antimicrobial peptide production and enhanced barrier function. IL-17-driven inflammation is normally controlled by regulatory T cells and the anti-inflammatory cytokines IL-10, TGFβ and IL-35. However, if dysregulated, IL-17 responses can promote immunopathology in the context of infection or autoimmunity. Moreover, IL-17 has been implicated in the pathogenesis of many other disorders with an inflammatory basis, including cardiovascular and neurological diseases. Consequently, the IL-17 pathway is now a key drug target in many autoimmune and chronic inflammatory disorders; therapeutic monoclonal antibodies targeting IL-17A, both IL-17A and IL-17F, the IL-17 receptor, or IL-23 are highly effective in some of these diseases. However, new approaches are needed to specifically regulate IL-17-mediated immunopathology in chronic inflammation and autoimmunity without compromising protective immunity to infection.

Risk of liver dysfunction and non-alcoholic fatty liver diseases in people with hidradenitis suppurativa: A systematic review and meta-analysis of real-world evidences

Background

To date, evidences with high evidence-level evaluating the association between liver diseases and hidradenitis suppurativa was lacking. Given that inconsistency exists in some of the previous observational studies, evaluating the prevalence of liver diseases in HS patients could potentially serve as a reference of future guidelines for HS comorbidity screening. The aim of the current study was to evaluate potential association between hidradenitis suppurativa and liver diseases and provide integrated evidences.

Methods

A search in PubMed, Web of Science and Embase based on the syntaxes ''hidradenitis suppurativa'' or ''acne inversa'' with "comorbidities", "liver diseases", "fatty liver" or "hepatitis" was performed. Observational studies evaluating epidemiological association between hidradenitis suppurativa and the risk of all liver diseases, including specific diseases as non-alcoholic fatty liver disease, hepatitis B, hepatitis C were targeted to be extracted in this systematic review and meta-analysis.

Results

Within the initial 702 records, there were finally 8 real-world observational studies extracted. Results suggest that patients with HS are associated with all liver diseases (OR= 1.50; 95% CI, 1.27, 1.76), non-alcoholic fatty liver disease (OR= 1.78; 95% CI, 1.28, 2.48) and hepatitis B (OR=1.48; 95% CI, 1.12, 1.94), but not hepatitis C (OR= 1.27; 95% CI, 0.78, 2.07). HS patients were associated with significantly increased risk of liver diseases, especially the risk of non-alcoholic fatty liver disease and hepatitis B.

Conclusions

Clinicians should be alert to the clinical relationship while caring people with hidradenitis suppurativa and the screening of liver function should be recommended to HS patients.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022296034.

Risk of psoriasis in people with hidradenitis suppurativa: A systematic review and meta-analysis

Background

Hidradenitis suppurativa were associated with comorbidities in various organ systems. Inflammatory dermatological diseases such as pyoderma gangrenosum were reported to be associated with hidradenitis suppurativa. Nevertheless, as for the association between hidradenitis suppurativa and psoriasis, evidences were insufficient. In many studies, the association between psoriasis and hidradenitis suppurativa has been reported. However, some evidence seems to be controversial. The purpose of the systematic review and meta-analysis was to assess whether there was significant association between HS and psoriasis.

Methods

On June 01, 2022, we appraised 2,795 articles from databases including PubMed, Web of Science and Embase. Search syntaxes were based on 'hidradenitis suppurativa' or 'acne inversa' with "psoriasis", "comorbidities" or 'epidemiology'. Synonyms were determined based on MeSH terms and Emtree. Observational results that evaluated the odds ratio for people with hidradenitis suppurativa who had psoriasis were extracted for qualitative synthesis.

Results

After the selection process of the initial 2,795 studies, ten observational studies, including 3 cohort studies, 1 case-control study, and 6 cross-sectional studies, were extracted for critical appraisal. Based on the integration of 7 studies (with more than 560,000 participants included), people with hidradenitis suppurativa had a higher risk of having psoriasis, with a 2.67-fold risk (95% CI, 1.84, 3.87). The association remained in the sensitivity analyses utilizing strict adjustment models. In the analysis that only included studies with a similar study design and adjustments in obesity-related factors, the risk of people with hidradenitis suppurativa having psoriasis was 3.24 (95% CI, 2.27, 4.62). In male patients with HS, the risk of having psoriasis was 4.30-fold higher than male patients without HS (95% CI, 2.37, 7.78). Likewise, in an analysis including 3 cross-sectional studies, the risk of female HS patients having psoriasis was 3.94-fold higher than female HS-free patients (95% CI, 2.34, 6.63).

Conclusions

The co-occurrence of hidradenitis suppurativa and psoriasis can greatly increase the burden of the disease. Psoriasis could be one of the critical comorbidities of hidradenitis suppurativa and should be recommended for future screening and follow up. The association between the two diseases should be kept in mind in managing hidradenitis suppurativa patients. More prospective studies are needed to establish the true magnitude of the association between psoriasis and hidradenitis suppurativa.

Pharmacological interventions for hidradenitis suppurativa: a protocol for systematic review and network meta-analysis of randomised trials and non-randomised studies

INTRODUCTION

Therapeutic recommendations for hidradenitis suppurativa (HS) have recently shifted towards non-invasive pharmacological options. Recent evidence has shown promising efficacy for specific treatments. However, data regarding the comparative efficacy of these treatments in patients with HS are still limited. Therefore, we plan to conduct a systematic review and network meta-analysis (NMA) to summarise the benefits and harms of different pharmacological interventions for treating people living with HS.

METHODS AND ANALYSIS

We will search electronic databases, including Medline, Embase, PubMed, Web of Science, Scopus, CINAHL and Cochrane Library beginning from their inception dates with no language restrictions. A grey literature search will be performed to supplement the electronic databases. Both randomised trials and non-randomised studies using validated measurement tools that investigated the benefits and harms of pharmacological interventions among people living with HS will be included. The predefined primary outcomes will include treatment responses that reflect the patient's perspective and all-cause discontinuation. Screening, selection, extraction, assessment of the risk of bias and analysis of the strength of the evidence will be performed independently by a pair of reviewers. A two-step approach of traditional pairwise and NMA will be performed. Based on a random-effects model, standardised weighted mean differences and ORs with corresponding 95% CIs will be pooled as effect estimates for the continuous and categorical endpoints, respectively. Statistical and methodological heterogeneities will be assessed. Preplanned subgroup analyses and univariate meta-regression will be conducted to quantify the potential sources of heterogeneity. Evidence-based synthesis will be based on the magnitudes of effect size, evidence certainty and the surface under the cumulative ranking curve values.

ETHICS AND DISSEMINATION

Ethical approval is not required because this study is based on existing published data. These findings will be disseminated through scientific meetings and publications in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42022302795.