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Introduction: Atopic dermatitis (AD) is a common, chronic inflammatory skin disorder driven by an intricate interplay of genetic, environmental, and immunological factors., Areas Covered: As a clinically heterogenous condition, AD may be stratified into subtypes based on factors including, chronicity, immunoglobulin E levels, severity, age, and ethnicity. Transcriptomic and proteomic analyses in skin and blood help elucidate the underlying molecular mechanisms of these AD subtypes, referred to as AD endotypes. Further characterizing AD endotypes using reliable biomarkers can facilitate the development of more effective and personalized therapeutics and improve our tools for monitoring disease progression and therapeutic response across a diverse subset of patients. Here, we aim to provide perspective on the latest research regarding AD stratification using skin and blood-based studies and insight into the implications of these findings on the future of AD research and clinical practice., Expert Opinion: The precise stratification of AD endotypes will allow for the development of reliable biomarkers and a more personalized medical treatment approach. Clinical practice and trials will eventually be able to bridge clinical with molecular data to optimize individualized treatments and more effectively monitor treatment response.

Hidradenitis suppurativa (HS) is a chronic inflammatory disease that is difficult to control, and its mechanism remains unclear. Hepatocyte GF (HGF) has been reported to be significantly upregulated in the serum and skin of patients with HS, especially in the lesions with tunnels. In this study, we examined the transcriptome of HGF-treated keratinocytes and compared it with genetic profiling of HS lesions. HGF was highly expressed in HS skin, especially in the deep dermis, compared with that in healthy controls, and its source was mainly fibroblasts. HGF upregulated more genes in keratinocytes than IL-17A or TNF-a, and these genes included multiple epithelial-mesenchymal transition-related genes. Differentially expressed genes in HGF-stimulated keratinocytes were involved in activation of epithelial-mesenchymal transition-related pathways. These HGF-induced genes were significantly upregulated in HS lesions compared with those in healthy skin and nonlesions and were more strongly associated with HS tunnels. In summary, HGF was highly expressed in HS and induced epithelial-mesenchymal transition-related genes in keratinocytes; HGF-induced genes were highly associated with gene profiling of HS with tunnels, suggesting that HGF may be involved in HS tunnel formation through epithelial-mesenchymal transition., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Secukinumab, an anti-interleukin (IL)-17A monoclonal antibody, induces histological and molecular resolution of psoriatic plaques by 12 weeks. However, the long-term effects of secukinumab on the molecular resolution of psoriatic inflammation remain unknown., Objectives: To investigate the molecular resolution of psoriasis following 52 weeks of secukinumab treatment., Methods: This was a two-part phase II randomized double-blinded placebo-controlled 52-week study of patients with moderate-to-severe psoriasis receiving secukinumab 300 mg (NCT01537432). Psoriatic lesional and nonlesional skin biopsies were obtained at baseline and at weeks 12 and 52, and the composition of the residual disease genomic profile (RDGP; i.e. 'molecular scar') of biopsies from secukinumab responders analysed., Results: After 52 weeks of treatment, 14 of 24 enrolled patients were considered to be clinical responders [≥ 75% improvement in Psoriasis Area and Severity Index (PASI 75)], 4 of 24 were considered to be nonresponders (< PASI 75) and 6 of 24 patients were lost to follow-up; both the histological and transcriptomic profiles of PASI 75 responders improved from week 12 to week 52. RDGP transcripts of histological responders only partially overlapped between weeks 12 and 52, despite a similar number of transcripts in each RDGP; specifically, four novel transcript subsets showed distinct expression dynamics between weeks 12 and 52 ('slow-resolving', 'recurring', 'persistent' and 'resolved'), with anti-inflammatory and immunomodulatory genes (e.g. SOCS1, CD207 and IL37) notably restored at week 52. Shorter disease duration prior to secukinumab treatment coincided with greater transcript improvements at weeks 12 and 52., Conclusions: Secukinumab improves the histological and molecular phenotype of psoriatic lesional skin up to 52 weeks of treatment; these results suggest possible mechanisms that drive long-term control of psoriasis., Competing Interests: Conflicts of interest F.K., N.H., T.P., A.G. and M.M. are all employed by Novartis Pharma AG, Basel, Switzerland. M.S.-F. and L.E.T. have been supported by Novartis Pharma AG through an institutional research grant. K.A.W. is a former employee of and shareholder in Ultivue, Novartis and Leica Biosystems/Danaher, and is a current employee of Roche Diagnostics Solutions. J.G.K. received grants from Novartis, Pfizer, Amgen, Lilly, Boehringer, Innovaderm, Bristol Myer Squibbs, Janssen, AbbVie, Paraxel, LEO Pharma, Vitae, Akros, Regeneron, Allergan, Novan, Biogen MA, Sienna, UCB, Celgene, Botanix, Incyte, Avillion and Exicure; and has received honoraria from Novartis, Pfizer, Amgen, Lilly, Boehringer, Biogen IDEC, AbbVie, LEO Pharma, Escalier, Valeant, Aurigne, Allergan, Asana, UCB, Sienna, Celgene, Nimbus, Menlo, Aristea, Sanofi, Sun Pharma, Almirall, Arena, BMS, Ventyx, Aclaris and Galapagos. M.S. declares no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Secukinumab is effective against a range of psoriatic manifestations. Investigating psoriasis (PsO) relapse following secukinumab discontinuation could provide insights into long-term PsO remission., Objectives: To examine PsO relapse rates on treatment discontinuation following 1 year of secukinumab treatment., Methods: This study (clinical trial number: NCT01544595) is an extension of the phase III ERASURE/FIXTURE studies in patients with moderate-to-severe plaque PsO. After 1 year of secukinumab 300 mg or 150 mg treatment, participants who had responded to treatment with a ≥ 75% reduction in Psoriasis Area and Severity Index (PASI 75) at week 52 were randomly assigned to receive placebo (n = 120 and n = 100, respectively). On relapse, patients receiving placebo were switched to their previous secukinumab dose. The study primary outcome was the nonrelapse rate after secukinumab withdrawal., Results: Following the last dose of secukinumab 300 mg, 20.8% (25/120) and 10.0% (12/120) of patients who switched to placebo did not relapse at 1 and 2 years after discontinuation, respectively. Patients who received secukinumab 150 mg for 1 year showed a lower proportion of nonrelapse following treatment discontinuation [14% (14/100) and 6% (6/100)] at 1 and 2 years, respectively. Patients who did not relapse maintained low mean PASI (2.8) at 1 year drug free vs. baseline (20.9); 1.7 at 2 years drug free vs. baseline (19.2), following an initial 52-week treatment with secukinumab 300 mg. Disease duration (P = 0.02) and severity (P = 0.02) were significantly associated with time to relapse in patients initially treated with secukinumab 300 mg; patients with shorter disease duration and lower baseline PASI remained relapse-free for longer., Conclusions: Following discontinuation of secukinumab, a proportion of patients stayed relapse-free. Further, patients with shorter disease duration remained relapse-free for longer, suggesting that earlier treatment with secukinumab may result in long-term clinical control of moderate-to-severe PsO., Competing Interests: Conflicts of interest M.L. has received grants from AbbVie, Amgen, Arcutis, Avotres, Boehringer Ingelheim, Cara therapeutics, Dermavant Sciences, Eli Lilly, Incyte, Inozyme, Janssen Research & Development, LLC, Ortho Dermatologics, Sanofi-Regeneron and UCB, and has received consulting fees from Almirall, AltruBio Inc., AnaptysBio, Arcutis, Inc., AstraZeneca, Avotres Therapeutics, Brickell Biotech, Boehringer Ingelheim, Bristol-Myers Squibb, Castle Biosciences, Celltrion, Corevitas, Dermavant Sciences, EPI, Evommune, Inc., Facilitation of International Dermatology Education, Forte Biosciences, Foundation for Research and Education in Dermatology, Galderma, Genentech, Incyte, LEO Pharma, Meiji Seika Pharma, Mindera, Pfizer, Seanergy, Strata, Trevi and Verrica. L.I. has served as a consultant and/or paid speaker for and/or participated in clinical trials sponsored by: AbbVie, Almirall, Amgen, Astra Zeneca, BMS, Boehringer Ingelheim, Celgene, Centocor, Eli Lilly, Janssen Cilag, Kyowa, Leo Pharma, MSD, Novartis, Pfizer, Regranion, Samsung and Union Therapeutics UCB. He is also an employee at MC2 Therapeutics A/S. L.E. has served as a consultant and/or paid speaker for and/or participated in clinical trials sponsored by AbbVie, Novartis, Janssen, Leo Pharma and ITN. J.G.K. received grants from Novartis, Pfizer, Amgen, Lilly, Boehringer, Innovaderm, Bristol Myer Squibb, Janssen, AbbVie, Paraxel, Leo Pharma, Vitae, Akros, Regeneron, Allergan, Novan, Biogen MA, Sienna, UCB, Celgene, Botanix, Incyte, Avillion and Exicure, and has received honoraria from Novartis, Pfizer, Amgen, Lilly, Boehringer, BiogenIdec, AbbVie, Leo Pharma, Escalier, Valeant, Aurigne, Allergan, Asana, UCB, Sienna, Celgene, Nimbus, Menlo, Aristea, Sanofi, Sun Pharma, Almirall, Arena, BMS, Ventyx, Aclaris and Galapagos NV. M.S.-F. and L.T. have been supported by Novartis through an institutional research grant. F.K. and M.M. are employed by Novartis Pharma AG (Basel, Switzerland). R.Y. is employed by China Novartis Institutes for BioMedical Research (Shanghai, China)., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.)

EFFISAYIL 1 was a randomized, placebo-controlled study of spesolimab, an anti-IL-36 receptor antibody, in patients presenting with a generalized pustular psoriasis flare. Treatment with spesolimab led to more rapid pustular and skin clearance versus treatment with placebo in approximately half of the patients. In this study, we present histologic, transcriptomic, and proteomic analyses of lesional and nonlesional skin and whole-blood samples collected from EFFISAYIL 1. Treatment with spesolimab led to a transition toward a nonlesional profile, with a downregulation of gene expressions in the skin of IL-36 transcripts (IL36α, IL36β, IL36γ) and those associated with neutrophil recruitment (CXCL1, CXCL6, CXCL8), proinflammatory cytokines (IL6, IL19, IL20), and skin inflammation (DEFB4A, S100A7, S100A8). Changes were manifest at week 1 and sustained to week 8. At the systemic level, reductions in serum biomarkers of inflammation (IL-17, IL-8, IL-6) were sustained until 12 weeks after spesolimab treatment. Considerable overlap was observed in the spesolimab-induced changes in gene and protein expressions from skin and blood samples, demonstrating the molecular basis of the effects of spesolimab on controlling local and systemic inflammation. Data are consistent with the mode of action of spesolimab, whereby inhibition of the IL-36 pathway leads to subsequent reductions in the key local and systemic pathologic events associated with generalized pustular psoriasis flares., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: While B-cells have historically been implicated in allergy development, a growing body of evidence supports their role in atopic dermatitis (AD). B-cell differentiation across ages in AD, and its relation to disease severity scores, has not been well defined., Objective: To compare the frequency of B-cell subsets in blood of 0-5, 6-11, 12-17, and ≥18 years old patients with AD versus age-matched controls., Methods: Flow cytometry was used to measure B-cell subset frequencies in the blood of 27 infants, 17 children, 11 adolescents, and 31 adults with moderate-to-severe AD and age-matched controls. IgD/CD27 and CD24/CD38 core gating systems and an 11-color flow cytometry panel were used to determine frequencies of circulating B-cell subsets. Serum total and allergen-specific IgE (sIgEs) levels were measured using ImmunoCAP®., Results: Adolescents with AD had lower frequencies of major B-cells subsets (p < .03). CD23 expression increased with age and was higher in AD compared to controls across all age groups (p < .04). In AD patients, multiple positive correlations were observed between IL-17-producing T-cells and B-cell subsets, most significantly non-switched memory (NSM) B-cells (r = .41, p = .0005). AD severity positively correlated with a list of B-cell subsets (p < .05). IL-9 levels gradually increased during childhood, reaching a peak in adolescence, paralleling allergen sensitization, particularly in severe AD. Principal component analysis of the aggregated environmental sIgE data showed that while controls across all ages tightly clustered together, adolescents with AD demonstrated distinct clustering patterns relative to controls., Conclusions: Multiple correlations between B-cells and T-cells, as well as disease severity measures, suggest a complex interplay of immune pathways in AD. Unique B-cell signature during adolescence, with concurrent allergen sensitization and IL-9 surge, point to a potentially wider window of opportunity to implement interventions that may prevent the progression of the atopic march., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Hidradenitis suppurativa (HS) is an inflammatory skin disease characterized by painful nodules, abscesses and purulent secretions in intertriginous regions. Intense pruritus frequently accompanies HS lesions, adding further discomfort for patients. While Th17 pathway activation is implicated in HS pathogenesis, disease mechanisms are still not fully understood, and therapeutics are lacking. Previous reports raise a potential role for eosinophils in HS, showing a strong association of eosinophil levels with disease severity. To investigate eosinophils in HS, we recruited patients and matched healthy controls and then performed flow-cytometry studies, eosinophil stimulation assays, and lesional skin staining for eosinophils. We found that HS patients reported similar levels of pain and itch. Compared to matched controls, HS blood exhibited decreased mature eosinophils and increased numbers of immature eosinophils, coupled with a significant increase in dermal eosinophilic infiltrates. Additionally, IL-17RA + eosinophils were highly and significantly correlated with multiple HS-related clinical scores. In both stimulated and unstimulated conditions, HS eosinophils showed an inflammatory phenotype versus controls, including an increase in costimulatory T- and B-cell markers (e.g. CD5 and CD40) following all stimulations (TNFα/IL-17A/IL-17F). These findings highlight the significance of pruritus in HS and suggest a higher turnover of eosinophils in HS blood, potentially due to the consumption of eosinophils in skin lesions. Our data delineate the features and functions of eosinophils in HS and suggest that eosinophils participate in disease pathogenesis, advancing Th17-related inflammation. Further studies are needed to investigate eosinophils' response to current HS treatments and their potential as a therapeutic target in the disease., (© 2024 The Author(s). Experimental Dermatology published by John Wiley & Sons Ltd.)

IL-23 is a cytokine produced by myeloid cells that drives the T helper 17 pathway and plays an essential role in the pathophysiology of plaque psoriasis. IL-23 activation initiates a cascade of cytokines subsequently inducing the expression of many psoriasis-related proteins. This study aimed to better understand the underlying mechanisms driving the differences between IL-23 and IL-17A blockade in patients with psoriasis and their implications for durability of clinical responses. Serum and/or skin biopsies were isolated from patients treated with guselkumab or secukinumab for evaluation of potential biomarkers of pharmacodynamic response to treatment. Guselkumab treatment led to significantly greater reductions of IL-17F and IL-22 serum levels than treatment with secukinumab at weeks 24 and 48, demonstrating sustained regulation of the IL-23/T helper 17 pathway. Analyses of proteomic and transcriptomic profiles of patient sera and skin biopsies demonstrated differential regulation of proteins involved in chemokine, TNF, and relevant immune signaling pathways to a greater degree with guselkumab than with secukinumab treatment. These data provide insights into the differences between the mechanisms and impact of IL-23 and IL-17A blockade in psoriasis, with implications for efficacy observations and treatment paradigms. Trial Registration: The original study was registered at ClinicalTrials.gov (NCT03090100)., (© 2024 The Authors.)

The autoimmune disease lupus erythematosus (lupus) is characterized by photosensitivity, where even ambient ultraviolet radiation (UVR) exposure can lead to development of inflammatory skin lesions. We have previously shown that Langerhans cells (LCs) limit keratinocyte apoptosis and photosensitivity via a disintegrin and metalloprotease 17 (ADAM17)-mediated release of epidermal growth factor receptor (EGFR) ligands and that LC ADAM17 sheddase activity is reduced in lupus. Here, we sought to understand how the lupus skin environment contributes to LC ADAM17 dysfunction and, in the process, differentiate between effects on LC ADAM17 sheddase function, LC ADAM17 expression, and LC numbers. We show through transcriptomic analysis a shared IFN-rich environment in non-lesional skin across human lupus and three murine models: MRL/lpr, B6.Sle1yaa, and imiquimod (IMQ) mice. IFN-I inhibits LC ADAM17 sheddase activity in murine and human LCs, and IFNAR blockade in lupus model mice restores LC ADAM17 sheddase activity, all without consistent effects on LC ADAM17 protein expression or LC numbers. Anti-IFNAR-mediated LC ADAM17 sheddase function restoration is associated with reduced photosensitive responses that are dependent on EGFR signaling and LC ADAM17. Reactive oxygen species (ROS) is a known mediator of ADAM17 activity; we show that UVR-induced LC ROS production is reduced in lupus model mice, restored by anti-IFNAR, and is cytoplasmic in origin. Our findings suggest that IFN-I promotes photosensitivity at least in part by inhibiting UVR-induced LC ADAM17 sheddase function and raise the possibility that anifrolumab ameliorates lupus skin disease in part by restoring this function. This work provides insight into IFN-I-mediated disease mechanisms, LC regulation, and a potential mechanism of action for anifrolumab in lupus., Competing Interests: TL, VZ, ES, MD, YC, KV, DO, PC, YL, WS, ST, KO, MR, IR No competing interests declared, AD, PL is an employee of AMPEL BioSolutions, but has no financial conflicts of interest to report, NS was awarded the Lupus Therapeutics: The Clinical Trial Network Infrastructure Grant, received by The Albert Einstein College of Medicine. The author received payment for lectures at the Congress of Clinical Rheumatology East and the Congress of Clinical Rheumatology West. The author has no other competing interests to declare, JL has received the grants F31 NIH GM136144 and T32 NIH GM008539. The author has received stock or stock options from NASDAQ/NYSE Ticker: FULC, ABCL, AVXL, VOR, MRNA, BNTX, SAVA, OCGN, CTMX, BCEL, GE. The author has no other competing interests to declare, WA received support for travel and attending Lupus 21st century meeting in 2021. The author has no other competing interests to declare, JZ received a grant from NIH NIAMS, and consulting fees from Hoth Therapeutics and Pfizer. The author received payment for participation on a Data Safety Monitoring Board/ Advisory Board for Hoth Therapeutics and acts as President elect for PASPCR. The author holds stock options from Hoth Therapeutics, FoxWayne Inc and YouV labs. The author has no other competing interests to declare, JK has received grant support from AbbVie, Akros, Allergan, Amgen, Avillion, Biogen, Botanix, Boehringer Ingelheim, Bristol-Myers Squibb, Exicure, Innovaderm, Incyte, Janssen, Kyowa Kirin, Lilly, Nimbus Lackshmi, Novan, Novartis, PAREXEL, Pfizer, Regeneron, UCB, Vitae Pharmaceuticals. The author received consulting fees from AbbVie, Aclaris, Allergan, Almirall, Amgen, Artax Biopharma, Arena, Aristea, Asana, Aurigene, Biogen Idec, Boehringer Ingelheim, Bristol-Myers Squibb, Escalier, Galapagos, Janssen, Kyowa Kirin, Lilly, MoonLake Immunotherapeutics, Nimbus, Novartis, Pfizer, Sanofi, Sienna Biopharmaceuticals, Sun Pharma, Target-Derm, UCB, Valeant, Ventyx. The author has no other competing interests to declare, NA has received the following grants: NIAMS AR080436-01, NIAMS R56AR078686-01 and NIH NIAMS 5R01 GRANT AR070234-05. The author received consulting fees from Immunitas, Shennon Bio and Janssen. The author received payment as a lecturer from 23 and me, Cellino and Bristol Meyer Squibb Genomics. They are also a board member of the Society of Investigative Dermatology. The author has no other competing interests to declare, AJ has received grants from the NIH and the VA and consulting fees from Pfizer. The author has no other competing interests to declare, CB The patent number is US10024844B2 and the title of the patent is "Identification of an inhibitor of iRhom1 or an inhibitor of iRhom2", which is also what the patent relates to. Carl Blobel and the Hospital for Special Surgery have identified iRhom2 inhibitors and have co-founded the start-up company SciRhom in Munich to commercialize these inhibitors, TL has received the following grants: NIH R01AI079178, NIH R21 AR081493, Department of Defense W81XWH-21-LRP-IPA, Lupus Research Alliance Lupus Innovation Award grant, Barbara Volcker Center for Women and Rheumatic Diseases grant. She has also received funding support from the St. Giles Foundation and A Lasting Mark Foundation. She has received consulting fees from Pfizer, and has a received payment from Bristol Meyers Squibb for giving a lecture. The author has received payment for attending Lupus 21st Century meeting. The author has no other competing interests to declare, (© 2024, Li, Zyulina, Seltzer et al.)

Hidradenitis Suppurativa (HS) is a chronic autoinflammatory skin disease with activated keratinocytes, tunnel formation and a complex immune infiltrate in tissue. The HS microbiome is polymicrobial with an abundance of commensal gram-positive facultative (GPs) Staphylococcus species and gram-negative anaerobic (GNA) bacteria like Prevotella, Fusobacterium and Porphyromonas with increasing predominance of GNAs with disease severity. We sought to define the keratinocyte response to bacteria commonly isolated from HS lesions to probe pathogenic relationships between HS and the microbiome. Type strains of Prevotella nigrescens, Prevotella melaninogenica, Prevotella intermedia, Prevotella asaccharolytica, Fusobacterium nucleatum, as well as Staphylococcus aureus and the normal skin commensal Staphylococcus epidermidis were heat-killed and co-incubated with normal human keratinocytes. RNA was collected and analysed using RNAseq and RT-qPCR. The supernatant was collected from cell culture for protein quantification. Transcriptomic profiles between HS clinical samples and stimulated keratinocytes were compared. Co-staining of patient HS frozen sections was used to localize bacteria in lesions. A mouse intradermal injection model was used to investigate early immune recruitment. TLR4 and JAK inhibitors were used to investigate mechanistic avenues of bacterial response inhibition. GNAs, especially F. nucleatum, stimulated vastly higher CXCL8, IL17C, CCL20, IL6, TNF and IL36γ transcription in normal skin keratinocytes than the GPs S. epidermidis and S. aureus. Using RNAseq, we found that F. nucleatum (and Prevotella) strongly induced the IL-17 pathway in keratinocytes and overlapped with transcriptome profiles of HS patient clinical samples. Bacteria were juxtaposed to activated keratinocytes in vivo, and F. nucleatum strongly recruited murine neutrophil and macrophage migration. Both the TLR4 and pan-JAK inhibitors reduced cytokine production. Detailed transcriptomic profiling of healthy skin keratinocytes exposed to GNAs prevalent in HS revealed a potent, extensive inflammatory response vastly stronger than GPs. GNAs stimulated HS-relevant genes, including many genes in the IL-17 response pathway, and were significantly associated with HS tissue transcriptomes. The close association of activated keratinocytes with bacteria in HS lesions and innate infiltration in murine skin cemented GNA pathogenic potential. These novel mechanistic insights could drive future targeted therapies., (© 2024 The Authors. Experimental Dermatology published by John Wiley & Sons Ltd.)

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., Competing Interests: JK served as a consultant for and/or received honoraria from AbbVie, Allergan, Almirall, Amgen, Arena, Aristea, Asana, Aurigene, Biogen Idec, Boehringer Ingelheim, Bristol Myers Squibb, Escalier, Galapagos, Janssen, Eli Lilly, MoonLake Immunotherapeutics, Nimbus, Novartis, Pfizer, Sanofi, Sienna Biopharmaceuticals, Sun Pharmaceutical Industries, Target-Derm, UCB, Valeant, and Ventyx. KE received speaker fees from and/or served on an advisory board for AbbVie, Almirall, Boehringer Ingelheim, Bristol Myers Squibb, Galapagos, Eli Lilly, Janssen, Pfizer, Novartis, Sanofi, and UCB. VK served as a consultant for iTeos; has an ownership interest in and is a member of the scientific advisory board for Tizona Therapeutics; is a cofounder of and has an ownership interest in Celsius Therapeutics; and is a cofounder of Bicara Therapeutics. CR received grant/research support and consulting fees from UCB, AbbVie, and Amgen; and received consulting fees from Eli Lilly, Pfizer, Novartis, Gilead, and Janssen. MA is a consultant or served on advisory boards for AbbVie Inc, Arena Pharmaceuticals Inc now Pfizer, Bristol Myers Squibb, Celsius Therapeutics, Eli Lilly and Company, Gilead Sciences Inc, Janssen Pharmaceuticals, Janssen Global Services, Pfizer Pharmaceutical, Prometheus Biosciences, UCB Biopharma SRL. She has received fees for lecturing from Alimentiv, Janssen Pharmaceuticals, Prime CME and WebMD Global LLC. IM received consulting fees and grant/research support from AstraZeneca, Bristol Myers Squibb, Amgen, Eli Lilly, GSK, Janssen, Novartis, Roche, and UCB; received consulting fees from AbbVie, Cabaletta, Compugen, Gilead, Pfizer, and Sanofi; serves as a shareholder of Compugen and Causeway Therapeutics, and as a board member for National Health Service Greater Glasgow and Clyde; and is a trustee for Versus Arthritis. ME, AF, SF, JS, Y-WY, and DC are employees of Janssen and hold stock in Johnson & Johnson. Box 1Questions to consider for future investigation to advance the science of IL-23 and approaches to IL-23 inhibitor therapy.A multiomics approach to advancing the science of IL-23 Are there any trends in the literature that identify how the IL-23/IL-17 axis may function and drive nuanced effects in different cell types or tissues?Does the impact of this pathway change over time or with progression of disease, identifying an ideal timeframe or context in the course of disease to initiate IL-23 inhibitor treatment?Are there any differences in biomarker profiles between inadequate responders and responders to therapy that may be used to predict clinical outcomes?What is the epigenetic profile of IL-23 signaling in various immune and non-immune cell types and how may this impact disease pathogenesis, disease progression, or response to treatment?What post-translational modifications of downstream cytokines/effector molecules are associated with IL-23 signaling?What are the functional consequences of changes in multiomics profiles and associated changes in immune cell populations over the course of disease and in response to treatment?“Broad sweep” of IL-23 receptor–expressing cells Which cells express the IL-23 receptor in healthy and inflamed tissues in humans?What is the role of IL-23 receptor signaling in diverse T-cell targets?How may a comprehensive assessment of IL-23 receptor expression across cell types and tissues identify new disease states that may be treatable through targeted intervention with IL-23 inhibition?How does IL-23 receptor expression change at various timepoints and tissue types across IMIDs and in response to treatment with IL-23 blockade?Is the IL-23 receptor coexpressed with other molecules of interest (ie, other cytokines or receptors) that may help to explain differences between currently available therapies and help design future treatments?Gaps in understanding IL-23 signaling and cellular activity Are there different nuances to IL-23 signaling in different cell types or tissues that may have functional consequences impacting disease pathogenesis or response to treatment?Do these signaling nuances change over the course of disease progression, and normalize with treatment with an IL-23 inhibitor?What is the role of STAT3 and STAT4 signaling in the context of IL-23 receptor signaling in Treg cells?What is the relationship between tissue-specific microbiota and IL-23 receptor signaling?Durability of response What is the effect of targeting IL-23p19 on TRM cells and the ratio of TRM/Treg cells across IMIDs?What are the mechanisms underlying the long-lasting effects of targeting IL-23p19?Can early intervention with IL-23 blockade after recent onset of disease modify the course of disease progression by suppressing TRM cells?Future IL-23 inhibitor molecules What molecular attributes of IL-23 inhibitors may be relevant for optimizing inhibition of IL-23 across IMIDs?Are there therapeutic advantages in targeting the IL-23 receptor versus IL-23p19 subunit directly in treating IMIDs?Combination therapy What potential therapeutic benefits may derive from combining IL-23 inhibition with blockade of another complementary inflammatory disease-driving pathway in treating IMIDs?What complementary pathway(s) would be optimal for blockade in combination with IL-23 inhibition for treatment of given IMIDs?IL, interleukin; STAT, signal transducer and activator of transcription; Treg, regulatory T., (Copyright © 2024 Krueger, Eyerich, Kuchroo, Ritchlin, Abreu, Elloso, Fourie, Fakharzadeh, Sherlock, Yang, Cua and McInnes.)

Background: Hidradenitis suppurativa (HS) is a chronic inflammatory disease with a considerable disease burden. Existing treatment options are limited and often suboptimal; a high unmet need exists for effective targeted therapies., Objective: To explore the effects of spesolimab treatment in patients with HS., Methods: This randomized, double-blind, placebo-controlled, proof-of-clinical-concept study was conducted at 25 centers across 12 countries from May 3, 2021, to April 21, 2022. Patients had moderate-to-severe HS for ≥1 year before enrollment. Patients were randomized (2:1) to receive a loading dose of 3600 mg intravenous spesolimab (1200 mg at Weeks 0, 1, and 2) or matching placebo, followed by maintenance with either 1200 mg subcutaneous spesolimab every 2 weeks from Week 4-10 or matching placebo. The primary endpoint was the percentage change from baseline in total abscess and inflammatory nodule (AN) count at Week 12. Secondary endpoints were the absolute change from baseline in International Hidradenitis Suppurativa Severity Score System (IHS4), percentage change from baseline in draining tunnel (dT) count, the proportion of patients achieving a dT count of zero, absolute change from baseline in revised Hidradenitis Suppurativa Area and Severity Index (HASI-R), the proportion of patients achieving Hidradenitis Suppurativa Clinical Response (HiSCR50), the proportion of patients with ≥1 flare (all at Week 12), and patient-reported outcomes (PROs)., Results: In this completed trial, randomized patients (N=52) received spesolimab (n=35) or placebo (n=17). The difference (95% confidence interval) versus placebo in least squares mean are reported. At Week 12, the percentage change in total AN count was similar between treatment arms: -4.1% (-31.7, 23.4). There was greater numerical improvement in the spesolimab arm, as measured by IHS4: -13.9 (-25.6, -2.3); percentage change from baseline in dT count: -96.6% (-154.5, -38.8); and the proportion of patients achieving a dT count of zero: 18.3% (-7.9, 37.5). Spesolimab treatment also improved HASI-R and HiSCR50 versus placebo. Spesolimab demonstrated a favorable safety profile, similar to that observed in trials in other diseases., Conclusions: This exploratory proof-of-clinical-concept study supports the development of spesolimab as a new therapeutic option in HS. ClinicalTrials.gov identifier: NCT04762277., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Association of Dermatologists.)

Background: Hidradenitis suppurativa (HS) has a high unmet need for better treatments. Biopsies are considered the gold standard for studying molecular alterations in skin. A reproducible, minimally invasive approach is needed for longitudinal monitoring in trials and in pediatric populations., Objective: To determine whether skin tape strips can detect molecular alterations in HS and identify biomarkers of disease activity., Methods: We performed RNA sequencing on tape strips collected from lesional and healthy-appearing (nonlesional) HS skin (n = 22) and healthy controls (n = 21). We correlated the expression of skin biomarkers between tape strips and a previously published gene-signature of HS biopsies., Results: Tape strips detected upregulation of known HS biomarkers (eg, Interleukin[IL]-17A) in nonlesional and/or lesional skin and also identified novel clinically actionable targets, including OX40 and JAK3. The expression of Th17 and tumor necrosis factor-α pathways were highly correlated between tape strips and biopsies. HS clinical severity was significantly associated with expression of biomarkers (eg tumor necrosis factor-α , IL-17 A/F, OX40, JAK1-3, IL-4R) in HS lesional and/or nonlesional skin., Limitations: Sample size. Tape stripping is limited in depth., Conclusion: This study validates tape strips as a minimally-invasive approach to identify cutaneous biomarkers in HS. This provides a novel avenue for monitoring treatment efficacy and a potential step toward individualized therapy in HS., Competing Interests: Conflicts of interest KN, HH, MM, EA, MK, MM, DGS, SB, SCW, SG, JCR have no conflicts to disclose. SK is an employee of Mount Sinai and a consultant for AbbVie, Eli Lilly, Glenmark, Ichnos Sciences, Janssen, and Novartis. She serves on the Advisory Boards for Eli Lilly, Glenmark, Ichnos Sciences, Janssen, Abbvie, Argenx, Regeneron-Sanofi, Novartis, and UCB. She has received research funds from Pfizer, AbbVie, BMS, Incyte, Galderma and Acelyrin, and speaker bureau for AbbVie, Regeneron-Sanofi, Lilly, UCB, Janssen, Arcutis and Leo. ABG has received honoraria as an advisory board member and consultant for Amgen, AnaptypsBio, Avotres Therapeutics, Boehringer Ingelheim, Bristol-Myers Squibb, Dice Therapeutics, Eli Lilly, Janssen, Novartis, Sanofi, UCB, and Xbiotech and has received research/educational grants from AnaptypsBio, Moonlake Immunotherapeutics AG, Novartis, Bristol-Myers Squibb, and UCB Pharma (all paid to Mount Sinai School of Medicine). JGK has acted as a consultant for and/or received honoraria from AbbVie, Aclaris, Allergan, Almirall, Amgen, Arena, Aristea, Asana, Aurigene, Biogen Idec, Boehringer Ingelheim, Bristol-Myers Squibb, Escalier, Galapagos, Janssen, Lilly, MoonLake Immunotherapeutics, Nimbus, Novartis, Pfizer, Sanofi, Sienna Biopharmaceuticals, Sun Pharma, Target-Derm, UCB, Valeant, and Ventyx. James Krueger has received grant support (to The Rockefeller University) from AbbVie, Akros, Allergan, Amgen, Avillion, Biogen, Botanix, Boehringer Ingelheim, Bristol-Myers Squibb, Exicure, Innovaderm, Incyte, Janssen, Kyowa Kirin, Lilly, Nimbus Lackshmi, Novan, Novartis, PAREXEL, Pfizer, Regeneron, UCB, and Vitae Pharmaceuticals. EGY has served as a consultant for AbbVie, Amgen, Allergan, Asana Bioscience, Celgene, Concert, Dermira, DS Biopharma, Escalier, Galderma, Glenmark, Kyowa Kirin, LEO Pharmaceuticals, Lilly, Mitsubishi Tanabe, Novartis, Pfizer, Regeneron, Sanofi, and Union Therapeutics; a member of advisory boards of Allergan, Asana Bioscience, Celgene, DBV, Dermavant, Dermira, Escalier, Galderma, Glenmark, Kyowa Kirin, LEO Pharma, Lilly, Novartis, Pfizer, Regeneron, and Sanofi; and a recipient of research grants from AbbVie, AnaptysBio, AntibioTx, Asana Bioscience, Boehringer-Ingelheim, Celgene, DBV, Dermavant, DS Biopharma, Galderma, Glenmark, Innovaderm, Janssen Biotech, Kiniksa Pharma, LEO Pharmaceuticals, Lilly, Medimmune, Sienna Biopharmaceuticals, Novan, Novartis, Ralexar, Regeneron, Pfizer, UCB, and Union Therapeutics., (Copyright © 2023 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

Background: Generalised pustular psoriasis (GPP) is a rare and chronic skin disease historically treated with therapies that were originally intended to treat plaque psoriasis (PsO). However, GPP and plaque PsO have distinct pathogeneses and clinical courses., Objectives: This study aimed to further characterise the unique genetic background of GPP by summarising evidence on the frequency and type of IL3 6RN gene mutation, a gene that normally suppresses proinflammatory responses, in patients with GPP compared to patients with GPP and plaque PsO, and patients with plaque PsO only., Methods and Results: A targeted literature review was conducted to identify studies reporting IL3 6RN mutations and/or HLA-Cw6 allele frequency in patients with GPP. Meta-analyses showed a significantly higher rate of IL3 6RN mutations in the GPP-only population compared to the GPP + plaque PsO population (OR 3.51; 95% CI 2.29, 5.38). Monoallelic mutations of IL3 6RN were found in up to 33.3%, and biallelic mutations in up to 73.2% of patients with GPP (GPP-only and GPP + plaque PsO), in contrast with mono- and biallelic frequencies of only 0%-11.9% and 0%, respectively, in patients with plaque PsO only. Mean age-of-onset ranged from 5.9 to 48.9 years old, with most studies reporting a GPP age-of-onset between 20 and 40 years old. Twenty-one mutations were identified in the biallelic state and three in monoallelic. The most reported mutations were c.115 + 6T > C (p. Arg10ArgfsX1) (18 studies); c.227 C > T (p.Pro76Leu) (10 studies); and c.338 C > T (p.Ser113Leu) (8 studies). Mutations varied depending on geography and ethnicity, with the most frequently reported mutation predominantly reported in East Asian studies and international studies that included Asian patients. Rates of HLA-Cw6 , the risk allele most strongly associated with plaque PsO, were 0%-28.6% for patients with GPP, similar to rates in the general population (10.5%-20%)., Conclusion: Considering the differences between GPP and plaque PsO in aetiology and disease symptoms, effective, GPP-specific treatment options are needed, and recent research suggests that blockade of IL-36 signalling may be an effective target for treatment of GPP., Competing Interests: BG is an employee of Boehringer Ingelheim International GmbH. AP and SH are employed by Symmetron Ltd and were commissioned by Boehringer Ingelheim to undertake the targeted literature review and conduct the analyses. The authors report no other conflicts of interest for this manuscript., (© 2024 The Authors. Skin Health and Disease published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists.)

Hidradenitis suppurativa (HS), also known as acne inversa, is a chronic disabling and debilitating inflammatory disease with a high unmet medical need. The prevalence of HS reported in most studies is 1-2%, although it is likely to be under-reported and estimates vary globally owing to variance in data collection methods, ethnicity, geographical location and under-diagnosis. HS is characterized by persistent, painful cutaneous nodules, abscesses and draining tunnels commonly affecting the axillary, anogenital, inguinal and perianal/gluteal areas. Over time, chronic uncontrolled inflammation results in irreversible tissue destruction and scarring. Although the pathophysiology of HS has not been fully elucidated, the tumour necrosis factor (TNF)-α and interleukin (IL)-17 pathways have an important role, involving multiple cytokines. Currently, treatment options include topical medications; systemic therapies, including repeated and/or rotational courses of systemic antibiotics, retinoids and hormonal therapies; and various surgical procedures. The anti-TNF-α antibody adalimumab is currently the only biologic approved by both the US Food and Drug Administration and the European Medicines Agency for HS; however, its efficacy varies, with a clinical response reported in approximately 50% of patients in phase III trials. HS is a rapidly evolving field of discovery, with a diverse range of agents with distinct mechanisms of action currently being explored in clinical trials. Several other promising therapeutic targets have recently emerged, and agents targeting the IL-17 and Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways are the most advanced in ongoing or completed phase III clinical trials. Alongside limited therapeutic options, significant challenges remain in terms of diagnosis and disease management, with a need for better treatment outcomes. Other unmet needs include significant diagnostic delays, thus missing the therapeutic 'window of opportunity'; the lack of standardized outcome measures in clinical trials; and the lack of established, well-defined disease phenotypes and biomarkers., Competing Interests: Conflicts of interest J.G.K. has been a consultant and/or received honoraria from AbbVie, Aclaris Therapeutics, Allergan, Almirall, Amgen, Arena, Aristea, Artax Biopharma, Asana, Aurigene, Biogen Idec, Boehringer Ingelheim, Bristol Myers Squibb, Escalier, Galapagos, Janssen, Kyowa Kirin, Lilly, MoonLake Immunotherapeutics, Nimbus, Novartis, Pfizer, Sanofi, Sienna Biopharmaceuticals, Sun Pharma, Target-Derm, UCB, Valeant and Ventyx Biosciences. J.F. has conducted advisory work for Janssen, Boehringer Ingelheim, Pfizer, Kyowa Kirin, LEO Pharma, Regeneron, ChemoCentryx, AbbVie and UCB; participated in trials for Pfizer, UCB, Boehringer Ingelheim, Eli Lilly and CSL; and received research support from Ortho Dermatologics and Sun Pharma. G.B.E.J. reports grants and/or personal fees from AbbVie, Coloplast, ChemoCentryx, LEO Pharma, LEO Foundation, AFYX, Incyte, InflaRx, Janssen-Cilag, Novartis, UCB, CSL Behring, Regeneron, Sanofi, Kymera and Viela Bio. A.B.K.’s institution received grants from AbbVie, Admirx, AnaptysBio, Aristea, Bristol Myers Squibb, Eli Lilly, Incyte, Janssen, MoonLake Immunotherapeutics, Novartis, Pfizer, UCB and Sonoma Bio. A.B.K. has received consulting fees from AbbVie, Alumis, Bayer, Bristol Myers Squibb, Boehringer Ingelheim, Eli Lilly, FIDE, Janssen, MoonLake Immunotherapeutics, Novartis, Pfizer, Priovant Therapeutics, Sonoma Bio, Sanofi, UCB, Target RWE and Ventyx Biosciences; royalties from BIDMC; holds stock in Ventyx Biosciences; and serves on the board of directors of Almirall. B.K. has acted as an investigator or received grants and/or honoraria from AbbVie, Almirall, Amgen, AstraZeneca, Biogen, Bristol Myers Squibb, Celgene, Janssen, Lilly, LEO Pharma, Merck, MoonLake Immunotherapeutics, Novartis, Pfizer and UCB Pharma. F.G.B. has received honoraria for participation in advisory boards, in clinical trials and/or as a speaker from AbbVie, AbbVie Deutschland, Boehringer Ingelheim Pharma, Novartis Pharma, UCB Pharma, Incyte, MoonLake Immunotherapeutics, Mölnlycke and Janssen-Cilag. K.N. declares no conflicts of interest. E.P. has served as a consultant, advisory board member, speaker, Principal Investigator and/or received research grants from AbbVie, Bristol Myers Squibb, Celgene, CHDR, Citryll, ChemoCentryx, Galderma, GSK, InflaRx, Janssen-Cilag, Kymera, Novartis and UCB. K.R. has served as an advisor and/or paid speaker for and/or participated in clinical trials sponsored by AbbVie, Almirall, Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Forward Pharma, Gilead, Galderma, Janssen-Cilag, Kyowa Kirin, LEO Pharma, Lilly, Medac, Novartis, Ocean Pharma, Pfizer, Sanofi and UCB. K.R. is co-founder and an employee of MoonLake Immunotherapeutics (Zug, Switzerland). E.C. is an employee of MoonLake Immunotherapeutics (Zug, Switzerland). K.W. has received research grants, travel grants, consulting honoraria or lecturer’s honoraria from AbbVie, AbbVie Deutschland, Celgene/BMS, Charité Research Organisation, Dr. Willmar Schwabe, Flexopharm, Janssen-Cilag, Novartis Pharma, Pfizer Deutschland, Sanofi-Aventis Deutschland, TFS and UCB Biopharma., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.)

Background: Our knowledge of etiopathogenesis of atopic dermatitis (AD) is largely derived from skin biopsies, which are associated with pain, scarring and infection. In contrast, tape-stripping is a minimally invasive, nonscarring technique to collect skin samples., Methods: To construct a global AD skin transcriptomic profile comparing tape-strips to whole-skin biopsies, we performed RNA-seq on tape-strips and biopsies taken from the lesional skin of 20 moderate-to-severe AD patients and the skin of 20 controls. Differentially expressed genes (DEGs) were defined by fold-change (FCH) ≥2.0 and false discovery rate <0.05., Results: We detected 4104 (2513 Up; 1591 Down) and 1273 (546 Up; 727 Down) DEGs in AD versus controls, in tape-strips and biopsies, respectively. Although both techniques captured dysregulation of key immune genes, tape-strips showed higher FCHs for innate immunity (IL-1B, IL-8), dendritic cell (ITGAX/CD11C, FCER1A), Th2 (IL-13, CCL17, TNFRSF4/OX40), and Th17 (CCL20, CXCL1) products, while biopsies showed higher upregulation of Th22 associated genes (IL-22, S100As) and dermal cytokines (IFN-γ, CCL26). Itch-related genes (IL-31, TRPV3) were preferentially captured by tape-strips. Epidermal barrier abnormalities were detected in both techniques, with terminal differentiation defects (FLG2, PSORS1C2) better represented by tape-strips and epidermal hyperplasia changes (KRT16, MKI67) better detected by biopsies., Conclusions: Tape-strips and biopsies capture overlapping but distinct features of the AD molecular signature, suggesting their respective utility for monitoring specific AD-related immune, itch, and barrier abnormalities in clinical trials and longitudinal studies., (© 2023 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Clinical overlaps between psoriasis and atopic dermatitis (AD) are sometimes undiscernible, and there is no consensus on whether to treat the overlap phenotype as psoriasis or AD. We enrolled 41 patients diagnosed with either psoriasis or AD and clinically re-stratified them into classic psoriasis (n = 11), classic AD (n = 13), and the overlap phenotype between psoriasis and AD (n = 17). We compared the gene expression profiles of lesional and nonlesional skin biopsy tissues and the proteomic profiles of blood samples among the three comparison groups. Global mRNA expression and T-cell subset cytokine expression in the skin and protein biomarker elevation in the blood of the overlap phenotype were consistent with the profiles of psoriasis and different from the profiles of AD. Unsupervised k-means clustering indicated that the best number of distinct clusters for the total population of the three comparison groups was two, and the two clusters of psoriasis and AD were differentiated by gene expression. Our study suggests that the clinical overlap phenotype between psoriasis and AD has dominant molecular features of psoriasis, and genomic biomarkers can differentiate psoriasis and AD at molecular levels in patients with a spectrum of psoriasis and AD., (Copyright © 2023. Published by Elsevier Inc.)

Melanoma accounts for the majority of skin cancer-related mortality, highlighting the need to better understand melanoma initiation and progression. In-depth molecular analysis of neoplastic melanocytes in whole tissue biopsies may be diluted by inflammatory infiltration, which may obscure gene signatures specific to neoplastic cells. Thus, a method is needed to precisely uncover molecular changes specific to tumor cells from a limited sample of primary melanomas. Here, we performed laser capture microdissection (LCM) and gene expression profiling of patient-derived frozen sections of pigmented lesions and primary cutaneous melanoma. Compared to bulk tissue analysis, analysis of LCM-derived samples identified 9528 additional differentially expressed genes (DEGs) including melanocyte-specific genes like PMEL and TYR, with enriched of pathways related to cell proliferation. LCM methodology also identified potentially targetable kinases specific to melanoma cells that were not detected by bulk tissue analysis. Taken together, our data demonstrate that there are marked differences in gene expression profiles depending on the method of sample isolation. We found that LCM captured higher expression of melanoma-related genes while whole tissue biopsy identified a wider range of inflammatory markers. Taken together, our data demonstrate that LCM is a valid approach to identify melanoma-specific changes using a relatively small amount of primary patient-derived melanoma sample., (© 2023 The Authors. Pigment Cell & Melanoma Research published by John Wiley & Sons Ltd.)

Generalized pustular psoriasis (GPP) is a rare, chronic, inflammatory skin disorder characterized by recurrent flares associated with skin erythema, desquamation, and widespread superficial sterile pustules, which may be severe ("lakes of pus"). Systemic symptoms are often present, including malaise, fever, and skin pain. In GPP, innate immune responses are driven by abnormal activation of the interleukin (IL)-36-chemokine-neutrophil axis and excessive neutrophil infiltration. This review highlights the IL-36 pathway in the context of the IL-1 superfamily and describes how unopposed IL-36 signaling can lead to the development of GPP. Targeted inhibition of the IL-36 receptor (IL-36R) is an attractive therapeutic strategy in the treatment of GPP, including flare prevention and sustained disease control. Spesolimab is a first-in-class, humanized, monoclonal antibody that binds specifically to the IL-36R and antagonizes IL-36 signaling. Spesolimab was approved by the US Food and Drug Administration in September 2022 to treat GPP flares in adults and was subsequently approved for GPP flare treatment in other countries across the world. Anti-IL-36R therapy, such as spesolimab, can mitigate flares and address flare prevention in GPP, presumably through rebalancing IL-36 signaling and modulating the pro-inflammatory response of the downstream effectors., Competing Interests: JH serves on the medical board and scientific advisory committee of the National Psoriasis Foundation, is a councilor for the International Psoriasis Council, and has been a paid consultant for AbbVie, Arcutis, BMS, Boehringer Ingelheim, Eli Lilly and Company, Janssen, LEO, Novartis, Pfizer, Regeneron-Sanofi, Sun Pharmaceutical, UCB, VisualDx, and UpToDate. SV is an employee of Boehringer Ingelheim Pharmaceuticals, Inc. JK has received grants from and been an investigator for Boehringer Ingelheim; received personal fees from AbbVie, Baxter, Biogen Idec, Delenex Therapeutics, Kineta, Sanofi, Serono, and XenoPort; and received grants from Amgen, Bristol Myers Squibb, Dermira, Innovaderm Research, Janssen, Kadmon, Kyowa Kirin, Eli Lilly, Merck, Novartis, Parexel, and Pfizer., (Copyright © 2023 Hawkes, Visvanathan and Krueger.)

Acute guttate psoriasis (AGP) is considered an uncommon variant of psoriasis (PsO), characterized as a widespread eruption of erythematous, psoriasiform papules, and plaques on the trunk, extremities, and scalp. Predisposing factors include a family history of PsO, variation in the main PsO susceptibility gene HLA-Cw*0602 , and previous infection with viruses or acute β-hemolytic Streptococcus A program focused on controversies and recent advances in understanding AGP was presented at the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) 2022 annual meeting. Topics included an overview of clinical presentation and natural history, predisposing genetic and environmental factors, and the recent molecular profiling that supports classification of AGP as a form of PsO. Early molecular profiling studies using proteomic signatures have suggested similarities between AGP and contact dermatitis, but recent studies using gene expression profiling and gene set enrichment scores demonstrate that AGP is more similar to chronic PsO. The expression of regulatory immune pathways seen with AGP suggests potential for early and sustained remission if the disease is suppressed by targeted treatments. Published case reports documenting clinical improvement of AGP with biologics that antagonize interleukin (IL)-12/23, IL-23, and IL-17 support the role of the IL-23/IL-17 axis in AGP, similar to that in PsO. Data supporting the use of antibiotics and other therapeutic agents for AGP are lacking, and randomized controlled trials are needed. Trial design for AGP is challenged by the low incidence, tendency for spontaneous remission, lack of validated end points, and the need for long-term follow up., (Copyright © 2023 by the Journal of Rheumatology.)

Competing Interests: Conflicts of interest: the authors declare no conflicts of interest.

Psoriasis is a chronic, systemic inflammatory condition primarily affecting skin. While the role of the immune compartment (e.g., T cells) is well established, the changes in the skin compartment are more poorly understood. Using longitudinal skin biopsies (n = 375) from the "Psoriasis Treatment with Abatacept and Ustekinumab: A Study of Efficacy"(PAUSE) clinical trial (n = 101), we report 953 expression quantitative trait loci (eQTLs). Of those, 116 eQTLs have effect sizes that were modulated by local skin inflammation (eQTL interactions). By examining these eQTL genes (eGenes), we find that most are expressed in the skin tissue compartment, and a subset overlap with the NRF2 pathway. Indeed, the strongest eQTL interaction signal - rs1491377616-LCE3C - links a psoriasis risk locus with a gene specifically expressed in the epidermis. This eQTL study highlights the potential to use biospecimens from clinical trials to discover in vivo eQTL interactions with therapeutically relevant environmental variables., (© 2023. Springer Nature Limited.)

Durable psoriasis improvement has been reported in a subset of psoriasis patients after treatment withdrawal of biologics blocking IL-23/Type 17 T-cell (T17) autoimmune axis. However, it is not well understood if systemic blockade of the IL-23/T17 axis promotes immune tolerance in psoriasis skin. The purpose of the study was to find translational evidence that systemic IL-17A blockade promotes regulatory transcriptome modification in human psoriasis skin immune cell subsets. We analyzed human psoriasis lesional skin 6 mm punch biopsy tissues before and after systemic IL-17A blockade using the muti-genomics approach integrating immune cell-enriched scRNA-seq (n = 18), microarray (n = 61), and immunohistochemistry (n = 61) with repository normal control skin immune cell-enriched scRNA-seq (n = 10) and microarray (n = 8) data. For the T17 axis transcriptome, systemic IL-17A blockade depleted 100% of IL17A + T-cells and 95% of IL17F + T-cells in psoriasis skin. The expression of IL23A in DC subsets was also downregulated by IL-17A blockade. The expression of IL-17-driven inflammatory mediators ( IL36G , S100A8 , DEFB4A , and DEFB4B ) in suprabasal keratinocytes was correlated with psoriasis severity and was downregulated by IL-17A blockade. For the regulatory DC transcriptome, the proportion of regulatory semimature DCs expressing regulatory DC markers of BDCA-3 ( THBD ) and DCIR ( CLEC4A ) was increased in posttreatment psoriasis lesional skin compared to pretreatment psoriasis lesional skin. In addition, IL-17A blockade induced higher expression of CD1C and CD14 , which are markers of CD1c + CD14 + dendritic cell (DC) subset that suppresses antigen-specific T-cell responses, in posttreatment regulatory semimature DCs compared to pretreatment regulatory semimature DCs. In conclusion, systemic IL-17A inhibition not only blocks the entire IL-23/T17 cell axis but also promotes regulatory gene expression in regulatory DCs in human psoriasis skin., Competing Interests: JK has received research funds from AbbVie and Novartis. JGK. has received research support from Pfizer, Amgen, Janssen, Lilly, Merck, Novartis, Kadmon, Dermira, Boehringer, Innovaderm, Kyowa, BMS, Serono, BiogenIdec, Delenex, AbbVie, Sanofi, Baxter, Paraxel, Xenoport, and Kineta. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Kim, Lee, Li, Kunjravia, Rambhia, Cueto, Kim, Chaparala, Ko, Garcet, Zhou, Cao and Krueger.)

Background: On the basis of the mounting evidence that type 17 T (T17) cells and increased IL-17 play a key role in driving hidradenitis suppurativa (HS) lesion development, biologic agents used previously in psoriasis that block signaling of IL-17A and/or IL-17F isoforms have been repurposed to treat HS., Objective: Our research aimed to characterize the transcriptome of HS T17 cells compared to the transcriptome of psoriasis T17 cells, along with their ligand-receptor interactions with neighborhood immune cell subsets., Methods: Single-cell data of 12,300 cutaneous immune cells from 8 deroofing surgical HS skin samples including dermal tunnels were compared to single-cell data of psoriasis skin (19,525 cells from 11 samples) and control skin (11,920 cells from 10 samples). All single-cell data were generated by the same protocol., Results: HS T17 cells expressed lower levels of IL23R and higher levels of IL1R1 and IL17F compared to psoriasis T17 cells (P < .05). HS Treg cells expressed higher levels of IL1R1 and IL17F compared to psoriasis Treg cells (P < .05). Semimature dendritic cells were the major immune cell subsets expressing IL1B in HS, and IL-1β ligand-receptor interactions between semimature dendritic cells and T17 cells were increased in HS compared to psoriasis (P < .05). HS dermal tunnel keratinocytes expressed inflammatory cytokines (IL17C, IL1A, IL1B, and IL6) that differed from the HS epidermis keratinocytes (IL36G) (P < .05). IL6, which synergizes with IL1B to maintain cytokine expression in T17 cells, was mainly expressed by fibroblasts in HS, which also expressed IL11 + inflammatory fibroblast genes (IL11, IL24, IL6, and POSTN) involved in the paracrine IL-1/IL-6 loop., Conclusion: The IL-1β-T17 cell cytokine axis is likely a dominant pathway in HS with HS T17 cells activated by IL-1β signaling, unlike psoriasis T17 cells, which are activated by IL-23 signaling., (Published by Elsevier Inc.)

Importance: The pathogenesis of eosinophilic cellulitis (EC) is poorly understood, limiting available treatment options. The current treatment paradigm focuses on delayed type 2 hypersensitivity reaction to various triggers., Objective: To gain further insight into the nature of EC inflammation and into the cellular signal transduction pathways that are activated in the context of EC., Design, Setting, and Participants: This case series was conducted in Lyon, France, from January 2018 to December 2021. Analysis of archival skin biopsy samples from patients with EC and from healthy control participants was performed using histology, Janus kinase (JAK)-signal transducer and activator of transcription (STAT) immunohistochemistry, and gene profiling. Data analysis was conducted between January 2020 and January 2022., Main Outcomes and Measures: Pruritus (visual analog score), percentage of body surface area with lesional skin, and RNA transcripts of inflammatory biomarkers from the skin (threshold cycle) were assessed in 1 index patient with refractory EC who received oral JAK1/JAK2 inhibitor baricitinib (4 mg/d)., Results: This study included samples from 14 patients with EC (7 men and 7 women) and 8 healthy control participants (4 men and 4 women). The mean (SD) age of patients was 52 (20) years. Marked type 2 inflammation (chemokines CCL17, CCL18, and CCL26 and interleukin 13) with preferential activation of the JAK1/JAK2-STAT5 pathways in EC lesions was observed. In the 1 index patient with refractory EC, complete clinical remission of skin lesions was observed after 1 month of treatment with baricitinib., Conclusions and Relevance: These findings suggest that EC is a type 2 inflammatory disease with preferential activation of the JAK1/JAK2-STAT5 pathways. In addition, these results suggest the potential of treatment approaches targeting JAK1/JAK2 for patients with EC.

Many Alzheimer's disease (AD) patients suffer from altered cerebral blood flow and damaged cerebral vasculature. Cerebrovascular dysfunction could play an important role in this disease. However, the mechanism underlying a vascular contribution in AD is still unclear. Cerebrovascular reactivity (CVR) is a critical mechanism that maintains cerebral blood flow and brain homeostasis. Most current methods to analyze CVR require anesthesia which is known to hamper the investigation of molecular mechanisms underlying CVR. We therefore combined spectroscopy, spectral analysis software, and an implantable device to measure cerebral blood volume fraction ( CBVF ) and oxygen saturation ( S O2 ) in unanesthetized, freely-moving mice. Then, we analyzed basal CBVF and S O2, and CVR of 5-month-old C57BL/6 mice during hypercapnia as well as during basic behavior such as grooming, walking and running. Moreover, we analyzed the CVR of freely-moving AD mice and their wildtype (WT) littermates during hypercapnia and could find impaired CVR in AD mice compared to WT littermates. Our results suggest that this optomechanical approach to reproducibly getting light into the brain enabled us to successfully measure CVR in unanesthetized freely-moving mice and to find impaired CVR in a mouse model of AD., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gareau, RochaKim, Choudhury, Bamkole, Snuderl, Zou, Yaroslavsky, Jacques, Strickland, Krueger and Ahn.)

Diphencyprone (DPCP) is a hapten that causes a delayed-type hypersensitivity reaction when applied topically. It has clinical uses in the treatment of various conditions such as melanoma metastases, warts, and alopecia areata, but the mechanisms are currently not well understood in humans. To further characterize the immunologic effects of DPCP, the authors performed a proteomic analysis of normal skin of eight healthy volunteers following a single application of DPCP and compared them with placebo-treated skin from the same volunteers. A total of 96 proteins were examined using the Olink immuno-oncology panel at 3 days (peak response), 14 days (partially resolved response), and 120 days (completely resolved response). Our analysis revealed significant upregulation of markers of immune cell activation (interleukin [IL] 8), vascular and tissue remodeling (matrix metallopeptidase 12 [MMP12], nitric oxide synthase 3 [NOS3]), antineoplastic markers (granzyme B [GZMB]), and the Th1 axis (interferon gamma [IFNG], chemokine (C-X-C motif) ligand [CXCL] 9, CXCL10, CXCL11) at days 3 and 14 compared with placebo (p < 0.05). In addition, several negative regulators of immune function such as programmed cell death 1 (PD1), programmed cell death ligand 1 (PDL1) (p < 0.001), and lymphocyte activation gene 3 (LAG3) (p < 0.05) were significantly upregulated at days 3 and 14. This induction of negative regulators may explain the seemingly paradoxical therapeutic benefits of DPCP in autoimmune conditions such as alopecia areata. The current analysis also indicated IL-4 upregulation only at day 3, followed by IL-12 upregulation only at day 14, suggesting a transient Th2 response followed by Th1 polarization. Overall, these data suggest a complex and evolving immunological delayed-type hypersensitivity response to a single application of DPCP over time. Future proteomic studies of samples from patients with melanoma metastases, warts, and alopecia areata treated long term with DPCP are needed to further evaluate its pharmacologic mechanisms., (© 2022 Japanese Dermatological Association.)

Background: Patients with atopic dermatitis (AD) have systemic biomarker dysregulation that differs by age group; however, the proteomic characteristics of these age-based changes are unknown., Objective: To profile blood proteins of patients with AD across different age groups versus age-appropriate controls., Methods: Using the Olink high-throughput proteomic platform, we profiled 375 serum proteins of 20 infants (age, 0-5 years), 39 children (age, 6-11 years), 21 adolescents (age, 12-17 years), and 20 adults (age, ≥18 years) with moderate-to-severe AD and 83 age-appropriate controls., Results: Each group presented a distinct systemic proteomic signature. Th2-related proteins were increased in infant AD and further intensified with age through adolescence and adulthood (interleukin 4/CCL13/CCL17). In contrast, Th1 axis down-regulation was detected in infants with AD and gradually reversed to increased Th1 products (interferon γ/CXCL9/CXCL10/CCL2) in patients with AD from childhood to adulthood. Despite their short disease duration, infants already had evidence of systemic inflammation, with significant upregulation of innate immunity (interleukin 17C/ interleukin-1RN), T-cell activation/migration (CCL19), Th2 (CCL13/CCL17), and Th17 (PI3) proteins. Adults with AD present unique upregulation of cardiovascular proteins related to coagulation and diabetes., Limitations: Cross-sectional observational study with a single time point., Conclusion: Systemic immune signatures of AD are age-specific beyond the shared Th2 immune activation. These data advocate for precision medicine approaches based on age-specific AD profiles., Competing Interests: Conflicts of interest Dr Guttman-Yassky is an employee of Mount Sinai; has received research funds (grants paid to the institution) from AbbVie, Celgene, Eli Lilly, Janssen, Medimmune/Astra Zeneca, Novartis, Pfizer, Regeneron, Vitae, Glenmark, Galderma, Asana, Innovaderm, Dermira, and UCB; and is a consultant for Sanofi Aventis, Regeneron, Stiefel/GlaxoSmithKline, MedImmune, Celgene, Anacor, AnaptysBio, Dermira, Galderma, Glenmark, Novartis, Pfizer, Vitae, Leo Pharma, AbbVie, Eli Lilly, Kyowa, Mitsubishi Tanabe, Asana Biosciences, and Promius. Dr Krueger has received research support (grants paid to his institution) and/or personal fees from Pfizer, Amgen, Janssen, Lilly, Merck, Novartis, Kadmon, Dermira, Boehringer, Innovaderm, Kyowa, BMS, Serono, BiogenIdec, Delenex, AbbVie, Sanofi, Baxter, Paraxel, Xenoport, and Kineta. Dr Paller has received research funds (grants paid to the institution) from AbbVie, AnaptysBio, Eli Lilly, Incyte, Janssen, KrystalBio, Regeneron, and UCB and is a consultant for AbbVie, Abeona, Acrotech, Almirall, Amgen, Amryt, Arcutis, Arena, Azitra, BioCryst, BiomX, Bridgebio, Bristol Myers Squibb, Castle Biosciences, Catawba, Eli Lilly, Exicure, Galderma, Kamari, Leo, Novan, Novartis, OM Pharma, Pfizer, Pierre Fabre, RAPT, Regeneron, Sanofi/Genzyme, Seanergy, and UCB. Dr Rangel has received research funds (grants paid to the institution) from AbbVie, DermTech, and Galderma. Drs Del Duca, Renert-Yuval, Pavel, Wu, Lefferdink, Fang, and Facheris and authors Mikhaylov, Sheth, Blumstein, and Estrada have no conflicts of interest to disclose., (Copyright © 2023 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.)

LL37 is produced by skin injury and bacterial infection and plays an important role in the early stages of psoriasis. In particular, the intracellular receptors toll-like receptors (TLR)3, TLR7, TLR8, and TLR9 are thought to be involved in the pathogenesis of psoriasis in conjunction with LL37, but the interaction between TLR7/8 and LL37 in keratinocytes (KCs) remains unclear. This study aimed to clarify the relationship between LL37 and TLR7/8 in KCs and their involvement in the pathogenetic pathways seen in psoriasis using cultured KCs and skin samples of patients with psoriasis. TLR7/8 was induced by LL37 in KCs. TLR8 but not TLR7 functionally induced many psoriasis-related molecules, whereas IL-17C was not altered by the blockade of TLR7/8. Although costimulation of LL37 with self-RNA/DNA did not show any interaction, LL37 itself would promote psoriasis-related genes. IL-36 receptor antagonistic antibody suppressed IL-17C induced by LL37. In psoriatic epidermis, LL37, TLRs, IL-17C, and IL-36γ expressions were increased and coexpressed with each other. Thus, we concluded that LL37 activates TLR8 in KCs and induces IL-17C through the induction of IL-36γ. Regulation of TLR8 or LL37 in KCs could be a potential therapeutic strategy for psoriatic inflammation., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Clinical trials are a vital component of translational science, providing crucial information on the efficacy and safety of new interventions and forming the basis for regulatory approval and/or clinical adoption. At the same time, they are complex to design, conduct, monitor, and report successfully. Concerns over the last two decades about the quality of the design and the lack of completion and reporting of clinical trials, characterized as a lack of "informativeness," highlighted by the experience during the COVID-19 pandemic, have led to several initiatives to address the serious shortcomings of the United States clinical research enterprise., Methods and Results: Against this background, we detail the policies, procedures, and programs that we have developed in The Rockefeller University Center for Clinical and Translational Science (CCTS), supported by a Clinical and Translational Science Award (CTSA) program grant since 2006, to support the development, conduct, and reporting of informative clinical studies., Conclusions: We have focused on building a data-driven infrastructure to both assist individual investigators and bring translational science to each element of the clinical investigation process, with the goal of both generating new knowledge and accelerating the uptake of that knowledge into practice., Competing Interests: A dedicated university counsel oversees clinical trial contracting, material transfer agreements, and the university’s conflict of interest program. She serves on both the ACCTS and the IRB, facilitating the flow of information on both topics to the appropriate committees.The authors have no disclosures to declare., (© The Author(s) 2023.)

Background: Atopic dermatitis (AD) is a heterogeneous, chronic inflammatory skin disease linked to skin microbiome dysbiosis with reduced bacterial diversity and elevated relative abundance of Staphylococcus aureus (S. aureus)., Objectives: We aimed to characterize the yet incompletely understood association between the skin microbiome and patients' demographic and clinical cofactors in relation to AD severity., Methods: The skin microbiome in 48 adult moderate-to-severe AD patients was investigated using next-generation deep sequencing (16S rRNA gene, V1-V3 region) followed by denoising (DADA2) to obtain amplicon sequence variant (ASV) composition., Results: In lesional skin, AD severity was associated with S. aureus relative abundance (r S  = 0.53, p < 0.001) and slightly better with the microbiome diversity measure Evenness (r S  = -0.58, p < 0.001), but not with Richness. Multiple regression confirmed the association of AD severity with microbiome diversity, including Shannon (in lesional skin, p < 0.001), Evenness (in non-lesional skin, p = 0.015) or S. aureus relative abundance (p < 0.012), and with patient's IgE levels (p < 0.001), race (p < 0.032), age (p < 0.034) and sex (p = 0.012). The lesional model explained 62% of the variation in AD severity, and the non-lesional model 50% of the variation., Conclusions: Our results specify the frequently reported "reduced diversity" of the AD-related skin microbiome to reduced Evenness, which was in turn mainly driven by S. aureus relative abundance, rather than to a reduced microbiome Richness. Finding associations between AD severity, the skin microbiome and patient's cofactors is a key aspect in developing new personalized AD treatments, particularly those targeting the AD microbiome., (© 2022 The Authors. Journal of the European Academy of Dermatology and Venereology published by John Wiley & Sons Ltd on behalf of European Academy of Dermatology and Venereology.)

Given the key role of the IL-23/Th17 axis in the pathogenesis of moderate-to-severe plaque psoriasis, several specific inhibitors of the p19 subunit of IL-23 have been approved to treat this chronic inflammatory disease. Clinical data indicate that guselkumab, one such selective IL-23 inhibitor, achieves greater clinical efficacy compared with ustekinumab, which inhibits both IL-12 and IL-23 via binding their shared p40 subunit. To understand mechanisms underlying the enhanced efficacy observed with the p19 subunit of IL-23-specific inhibition, we explored cellular and molecular changes in skin of psoriasis patients treated with ustekinumab or guselkumab and in ustekinumab inadequate responders (Investigator's Global Assessment of psoriasis score ≥ 2) subsequently treated with guselkumab (ustekinumab→guselkumab). Skin biopsies were collected pretreatment and posttreatment to assess histologic changes and molecular responses in ustekinumab- and guselkumab-treated patients. Serum cytokines and skin transcriptomics from the subset of ustekinumab→guselkumab-treated patients were also analyzed to characterize differential treatment effects. Ustekinumab and guselkumab demonstrated differential effects on secretion of pathogenic Th17-related cytokines induced by IL-23 in in vitro assays, which suggest guselkumab is a more potent therapeutic agent. Consistent with these findings, guselkumab elicited a significantly greater reduction in cellular and molecular psoriasis-related disease indicators than ustekinumab. In ustekinumab→guselkumab patients, suppression of serum IL-17A and IL-17F levels and neutralization of molecular scar and psoriasis-related gene markers in skin were significantly greater compared with patients continuing ustekinumab. This comparative study demonstrates that guselkumab inhibits psoriasis-associated pathology, suppresses Th17-related serum cytokines, and normalizes the psoriasis skin gene expression profile more effectively than ustekinumab., (Copyright © 2023 The Authors.)

Background: The mechanisms driving alopecia areata (AA) are still unclear, hindering development of targeted therapeutics. Specific Th2 targeting with dupilumab in AA provides a unique opportunity to dissect its pathogenesis and explore the role of Th2 pathway., Methods: We evaluated changes in scalp biomarkers in AA patients (with and without concomitant atopy) randomized to weekly dupilumab or placebo for 24 weeks, followed by open-label dupilumab for 24 weeks. Changes in biomarker levels were measured at weeks 12, 24, and 48 and were also correlated with clinical hair regrowth., Results: At week 24, preceding clinical hair regrowth outcomes, only dupilumab-treated patients presented significant suppression of cellular infiltrates, and multiple Th2-related, markers (CCL13/MCP-4, CCL18/PARC, CCL26/eotaxin-3, CCL24/Eotaxin-2), coupled with significant upregulation in the hair keratins. Th1-related suppression was evident later (week 48) when all patients received open-label dupilumab. Results were more pronounced in atopic AA patients, that showed 48% and 97% improvements in the lesional AA scalp profile at weeks 24 and 48, respectively, while 2% worsening was seen in the placebo arm at week 24. Moreover, placebo-treated patients presented 54% worsening in hair keratins when compared with baseline at week 24. At week 24, increases in hair keratins showed significant correlations only with decreases in Th2-related markers., Conclusions: Scalp biomarkers provide evidence of dupilumab efficacy in AA, detected even prior to clinical response, with exclusive correlations between early suppression of Th2 markers and increased hair keratins. These findings strengthen previous reports suggesting a possible role for Th2 cytokines as AA drivers., (© 2022 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Competing Interests: Conflicts of interest Dr Krueger has received research support (grants paid to the institution) from AbbVie, Amgen, BMS, Boehringer, EMD Serono, Innovaderm, Kineta, LEO Pharma, Novan, Novartis, Paraxel, Pfizer, Regeneron, and Vitae and personal fees from AbbVie, Acros, Allergan, Aurigne, BiogenIdec, Boehringer, Escalier, Janssen, Lilly, Novartis, Pfizer, Roche, and Valeant. The other authors have no conflicts of interest to declare.

Diphencyprone (DPCP), a topical contact sensitizer, has shown efficacy in treating cutaneous melanoma metastases, including at times beyond the directly treated sites, but biomarkers indicative of treatment response have not been characterized. Thus, we performed a proteomic analysis of the skin and serum of five patients with cutaneous melanoma metastases treated with DPCP on days 0, 63, and 112 of the treatment course. In the serum, we found a significant upregulation ( P < 0.05) in 13 of 96 assessed immuno-oncology proteins after DPCP treatment. Upregulated proteins included those of the T helper 1 axis (CXCL9, CXCL10), immune checkpoint proteins (PD-1), and various proteins with roles in promoting tumor immunity such as CD80 and TNFRSF4/9. Given the positive clinical response to topical treatment noted in the five patients studied, these proteins may represent prognostic biomarkers in the serum for evaluating the efficacy of DPCP treatment of cutaneous melanoma metastases. Because DPCP does not lead to nonspecific immune-related adverse events seen with immune checkpoint inhibitors, our study provides evidence for potential tumor-specific systemic immune activation and systemic antitumor effectors elicited by topical DPCP., (© 2023 The Authors.)

Background: Treatment of inflammatory skin diseases, including atopic dermatitis (AD) and psoriasis, is undergoing transformative changes, highlighting the need to develop experimental models of skin inflammation in humans to predict treatment responses., Methods: We topically or intradermally administered four common sensitizers (dust mite (DM), diphencyprone (DPCP), nickel (Ni), and purified protein derivative (PPD)) to the backs of 40 healthy patients and the skin hypersensitivity response was biopsied and evaluated using immunohistochemistry, RNA-seq, and RT-PCR., Results: All agents induced strong increases in cellular infiltrates (T-cells and dendritic cells) as compared to untreated skin (p < .05), with variable T helper polarization. Overall, DPCP induced the strongest immune responses across all pathways, including innate immunity (IL-1α, IL-8), Th1 (IFNγ, CXCL10), Th2 (IL-5, CCL11), and Th17 (CAMP/LL37) products, as well as the highest regulatory tone (FOXP3, IL-34, IL-37) (FDR <0.01). Nickel induced Th17 (IL-17A), Th1 (CXCL10) and Th2 (IL-4R) immune responses to a lesser extent than DPCP (p < .05). PPD induced predominantly Th1 (IFNγ, CXCL10, STAT1) and Th17 inflammation (IL-17A) (p < .05). DM induced modulation of Th2 (IL-13, CCL17, CCL18), Th22 (IL-22), and Th17/Th22 (S100A7/9/12) pathways (p < .05). Barrier defects that characterize both AD and psoriasis were best modeled by DPCP and Ni, followed by PPD, including downregulation of terminal differentiation (FLG, FLG2, LOR, LCEs), tight junction (CLDN1/CLDN8), and lipid metabolism (FA2H, FABP7)-related markers., Conclusion: Our data imply that DPCP induced the strongest immune response across all pathways, and barrier defects characteristic of AD and psoriasis., (© 2022 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: The IL-17A inhibitor secukinumab has demonstrated consistent efficacy and safety in patients with moderate-to-severe plaque psoriasis, with normalization of molecular and histopathologic psoriasis markers., Objective: To investigate treatment effects of secukinumab on clinical signs and psoriatic inflammation markers over 52 weeks in patients with psoriasis., Methods: In the ObePso-S study (NCT03055494), patients with psoriasis were randomized 2:1 to receive secukinumab 300 mg (n = 54) or placebo (n = 28), stratified by body weight (<90 or ≥90 kg), for 52 weeks. At Week 12, patients receiving placebo were switched to secukinumab. Psoriasis Area and Severity Index improvement of 90% (PASI90) and Investigator's Global Assessment modified 2011 0/1 responses were assessed at Weeks 12 and 52. Immunohistochemistry for keratin 16 (K16) and gene expression profiles were evaluated in lesional and non-lesional skin biopsies collected at baseline, Week 12, and Week 52., Results: Of patients receiving secukinumab, 55.8% and 59.6% achieved PASI90 at Weeks 12 and 52, respectively. K16 was absent in 93.1% of Week 12 PASI90 responders and 93.6% of Week 52 PASI90 responders, which mirrored the down-regulated expression of psoriatic inflammation. Week 52 PASI90 non-responders experienced regression of clinical and inflammatory marker responses toward baseline levels. Lower control of inflammatory gene expression at Week 12 was associated with suboptimal clinical responses at Week 52., Conclusion: Sustained clinical responses with secukinumab were associated with rapid and sustained normalization of K16 and inflammatory gene expression in most patients. Molecular anti-inflammatory effects of secukinumab at Week 12 were associated with clinical responses at Week 52., Competing Interests: Conflicts of interest A. Blauvelt has served as a speaker/received honoraria from AbbVie and UCB; has served as a scientific advisor/received honoraria from AbbVie, Abcentra, Affibody, Aligos, Almirall, Alumis, Amgen, AnaptysBio, Arcutis, Arena, ASLAN, Athenex, Boehringer Ingelheim, Bristol Myers Squibb, Cara Therapeutics, Dermavant, EcoR1, Eli Lilly, Evelo, Evommune, Forte, Galderma, HighlightII Pharma, Incyte, Janssen, Landos, LEO Pharma, Merck, Novartis, Pfizer, Rapt, Regeneron, Sanofi Genzyme, Spherix Global Insights, Sun Pharma, TLL Pharmaceutical, TrialSpark, UCB, Vibliome, and Xencor; and has acted as a clinical study investigator/his institution has received clinical study funds from AbbVie, Acelyrin, Amgen, Arcutis, Athenex, Boehringer Ingelheim, Bristol Myers Squibb, Dermavant, Eli Lilly, Evelo, Galderma, Incyte, Janssen, LEO Pharma, Merck, Novartis, Pfizer, Regeneron, Sun Pharma, and UCB. D.M. Pariser has served as a consultant for and received honoraria from Abbott, Amgen, Astellas, Bausch Health, Bickel Biotechnology, Celgene, Dermira, DUSA, LEO Pharma, MELA Sciences, Novartis, and Procter & Gamble; has participated in advisory boards and received honoraria from Galderma, Genentech, Janssen Ortho, Medicis, Ortho Dermatologics, Pfizer, and Stiefel; and has served as an investigator for and received research grants from Abbott, Amgen, Astellas, Asubio, Basliea, Bausch Health, Celgene, Dow Pharmaceutical Sciences, Eli Lilly, Galderma, Graceway, Intendis, Johnson & Johnson, LEO Pharma, Novartis, Novo Nordisk, Ortho Dermatologics, Peplin, Pfizer, Photocure ASA, and Stiefel. S. Tyring has served as an investigator for Novartis. J. Bagel has served as an investigator, consultant, and/or speaker for AbbVie, Amgen, Bausch Health, Boehringer Ingelheim, Celgene, Eli Lilly, Janssen, LEO Pharma, Novartis, and Sun Pharma. A.F. Alexis has received grants or research support from AbbVie, Almirall, Amgen, Arcutis, ASLAN, Bristol Myers Squibb, Cara Therapeutics, Castle, Dermavant, Galderma, LEO Pharma, Novartis, Valeant (Bausch Health), and Vyne; has served as a consultant or on advisory boards for AbbVie, Allergan, Almirall, Amgen, Arcutis, Bausch Health, Beiersdorf, Bristol Myers Squibb, Cara Therapeutics, Cutera, Dermavant, Eli Lilly, EPI, Galderma, Janssen, LEO Pharma, L′Oréal, Novartis, Pfizer, Sanofi-Regeneron, Sol-Gel, Swiss American, UCB, Valeant (Bausch Health), VisualDx, and Vyne; and has served as a speaker for Bristol Myers Squibb, Pfizer, Regeneron, and Sanofi-Genzyme. J. Soung has received speaker honoraria from AbbVie, Actelion, Amgen, Celgene, Dermira, Eli Lilly, National Psoriasis Foundation, Novartis, Ortho Dermatologics, and Regeneron; has received consulting/advisory board honoraria from Eli Lilly, LEO Pharma, and Novartis; and has received grant/research grant funding from AbbVie, Actavis, Actelion, Allergan, Boehringer Ingelheim, Cassiopea, Dr Reddy’s, Galderma, GSK, Janssen, Kadmon, Kyowa Kirin, LEO Pharma, Menlo, Novan, Novartis, Ortho Dermatologics, Pfizer, and UCB. A.W. Armstrong has served as research investigator and/or scientific advisor to AbbVie, ASLAN, Boehringer Ingelheim, Bristol Myers Squibb, Dermavant, Dermira, Eli Lilly, EPI, Incyte, Janssen, LEO Pharma, Modmed, Novartis, Ortho Dermatologics, Pfizer, Regeneron, Sanofi, Sun Pharma, and UCB. E. Muscianisi, F. Kianifard, R. Prasad Sarkar, and J. Steadman are employees and stockholders of Novartis. S. Garcet has nothing to disclose. J.G. Krueger has received grants paid to The Rockefeller University from Amgen, Boehringer Ingelheim, Bristol Myers Squibb, Dermira, Eli Lilly, Innovaderm, Janssen, Kadmon, Kineta, Kyowa, LEO Pharma, Novartis, Paraxel, Pfizer, Provectus, Regeneron, and Vitae; and has received personal fees from AbbVie, Baxter, Biogen Idec, Boehringer Ingelheim, Bristol Myers Squibb, Delenex, Dermira, Eli Lilly, Janssen, Kadmon, Kineta, Merck, Novartis, Pfizer, Sanofi, EMD Serono, and XenoPort., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Palmoplantar pustular psoriasis (PPPP) and non‒pustular palmoplantar psoriasis (NPPP) are localized, debilitating forms of psoriasis. The inflammatory circuits involved in PPPP and NPPP are not well-understood. To compare the cellular and immunological features that differentiate PPPP and NPPP, skin biopsies were collected from a total of 30 participants with PPPP, NPPP, and psoriasis vulgaris (PV) and from 10 healthy participants. A subset consented to a second biopsy after 3 additional weeks off medication. Histologic staining of lesional and nonlesional skin showed higher neutrophil counts in PPPP than in NPPP and PV and higher CD8 + T-cell counts in NPPP. RNA sequencing and transcriptional analysis of skin biopsies showed enhanced IFN-γ pathway activation in NPPP lesions but stronger signatures of IL-17 pathway and neutrophil-related genes (e.g., IL36A) in PPPP lesional skin. Serum analysis on the Olink platform detected higher concentrations of T helper type 1, IFN-γ‒inducible chemokines in NPPP, and higher neutrophil-associated cytokines in PPPP. Taken together, this evidence suggests more pronounced T helper 1‒mediated inflammation in NPPP than in PV and PPPP and stronger neutrophil-associated activity in PPPP than in NPPP and PV. These data support targeting inflammatory pathways associated with neutrophilic inflammation (e.g., IL-36 signaling) for therapeutic development in PPPP., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Immune checkpoint inhibitors (ICIs) such as pembrolizumab have revolutionized the treatment of advanced melanoma, but many patients do not respond to ICIs alone, and thus there is need for additional treatment options. Topical immunomodulators such as diphencyprone (DPCP) also have clinical use in advanced melanoma, particularly in the treatment of cutaneous metastases. In a previous report, we characterized the enhanced clinical response to dual agent immunotherapy with pembrolizumab and DPCP in a patient with cutaneous melanoma metastases. To improve mechanistic understanding of this response, we analyzed proteomic data using the Olink immuno-oncology panel of 96 biomarkers from tissue and serum samples of this patient throughout his treatment course. Particular attention was paid to programmed death-1 (PD-1), programmed death-ligand 1 (PD-L1), and lymphocyte-activation gene 3 (LAG-3) given they are all targeted by ICIs in clinical practice. These proteins were upregulated during the period of DPCP monotherapy, then downregulated during pembrolizumab monotherapy, and then robustly upregulated again during dual therapy. Although not exclusively, the induction of checkpoint inhibitor proteins in the presence of DPCP suggests potential synergy between this agent and ICIs in the treatment of cutaneous melanoma metastases. Large-scale investigation is warranted to further evaluate this potential novel combination therapeutic approach., (© 2022. The Author(s).)

Despite multiple efficacious therapies in common between psoriasis (PS) and Ulcerative Colitis (UC), mechanisms underlying their common pathophysiology remain largely unclear. Here we sought to establish a link by evaluating expression differences and pathway alterations in diseased tissues. We identified two sets of differentially expressed genes (DEGs) between lesional and nonlesional tissues in meta-analyses of data collected from baseline samples in 3 UC and then 3 PS available clinical studies from Pfizer. A shared gene signature was defined by 190 DEGs common to both diseases. Commonly dysregulated pathways identified via enrichment analysis include interferon signaling, partly driven by genes IFI6, CXCL9, CXCL10 and CXCL11, which may attract chemotaxis of Th1 cells to inflammatory sites; IL-23 pathway (IL-23A, CCL20, PI3, CXCL1, LCN2); and Th17 pathway except IL-17A. Elevated expression of costimulatory molecules ICOS and CTLA4 suggests ongoing T-cell activation in both diseases. The clinical value of the shared signature is demonstrated by a gene set improvement score reflecting post-treatment molecular improvement for each disease. This is the first study using transcriptomic meta-analysis to define a tissue gene signature and pathways dysregulated in both PS and UC. These findings suggest immune mechanisms may initiate and sustain inflammation similarly in the two diseases., (© 2022. The Author(s).)

Background: Although alopecia areata (AA) greatly impacts patients' quality of life (QoL), there is no adequate validation of AA-targeted QoL surveys in clinical trials, hindering sufficient representation of patient-reported outcomes., Objectives: Better understanding of patient-reported outcomes may guide treatment goals and future clinical trials., Methods: In a recent randomized controlled trial testing dupilumab in AA, patients were administered the Alopecia Areata Quality of Life Index (AA-QLI) and the Alopecia Areata Symptom Impact Scale (AASIS) surveys, specifically evaluating QoL in patients with AA. An in-depth analysis was performed to assess the utility of these questionnaires in this patient population, both at baseline and after treatment, and to determine a threshold for improved patient-reported outcomes., Results: While AASIS correlated with baseline Severity of Alopecia Tool (SALT) scores and with therapeutic response, AA-QLI showed no correlation with AA severity before or after treatment. Itch strongly correlated with serum IgE levels across both surveys. Using various approaches to estimate a discriminative threshold for decreased impact of AA on QoL (by AASIS) following treatment, a SALT score of 20 points or less post-treatment was associated with improved patient-reported outcomes, including both AA-related symptoms and items within the daily activities/feelings domain such as 'feeling sad' and 'feeling anxious or worry'., Conclusions: AASIS is better than AA-QLI to assess patient-reported outcomes. SALT ≤ 20 following treatment should be considered as a threshold for meaningful therapeutic outcome and as a clinical endpoint in future clinical trials for AA. What is already known about this topic? Alopecia areata greatly compromises quality of life, and affected patients have increased prevalences of depression, anxiety and social phobia. Despite the significant negative impact of the disease on patients' wellbeing, validation of targeted questionnaires in alopecia areata is lacking, and a therapeutic response threshold for improved patient-reported outcomes is unknown. What does this study add? This study investigated the utility of two different alopecia areata-targeted questionnaires - Alopecia Areata Quality of Life Index and Alopecia Areata Symptom Impact Scale (AASIS) - in a clinical trial setting. AASIS was found to correlate strongly with alopecia areata severity and clinical response. What are the clinical implications of this work? Patients with ≤ 20% scalp hair loss after treatment reported improvement in multiple quality-of-life items, suggesting this as a meaningful therapeutic outcome that may guide clinicians and improve the development of future clinical trials., (© 2022 British Association of Dermatologists.)

Introduction: Generalized pustular psoriasis (GPP) is a rare, severe, clinically heterogeneous disease characterized by flares of widespread, noninfectious, macroscopically visible pustules that occur with or without systemic inflammation, and are associated with significant morbidity and mortality. Historically, GPP has been classified as a variant of psoriasis vulgaris (PV, or plaque psoriasis); however, accumulating evidence indicates that these are distinct conditions, requiring different treatment approaches., Areas Covered: In this perspective article we review evidence that supports the classification of GPP as distinct from PV., Expert Opinion: The histopathologic and clinical appearance of GPP is distinct from that of PV and fundamental differences exist between the two conditions in terms of genetic causes and expression-related mechanisms of disease development. GPP results from dysregulation of the innate immune system, with disruption of the interleukin (IL)-36 inflammatory pathway, induction of inflammatory keratinocyte responses, and recruitment of neutrophils. PV is driven by the adaptive immune system, with a key role played by IL-17. Considering GPP as a separate disease will enable greater focus on its specific pathogenesis and the needs of patients. Many treatments for PV have insufficient efficacy in GPP and a therapeutic approach developed specifically for GPP might lead to better patient outcomes.

Psoriasis increases the risk of cardiovascular disease (CVD). Biomarkers for cardiovascular (CV) risk stratification in psoriasis are lacking, and the effects of psoriasis biologics on CV risk reduction remain unclear. The goal of this study was to identify biomarkers of CV risk in psoriasis blood that are reduced by ustekinumab. We quantified 276 inflammatory and CV-related serum proteins with Olink's multiplex assay in 10 psoriasis patients (vs. 18 healthy controls) and after 12 weeks of ustekinumab treatment. For each protein down-regulated after treatment, the literature was reviewed for studies assessing the protein's association with CVD. Data were collected from each study to calculate CV risk thresholds for each protein, which were compared with protein levels in psoriasis patients before and after treatment. Our results showed that 43 out of 276 proteins were down-regulated after treatment, 25 of which were initially up-regulated at baseline (vs. controls, all p-values ≤0.1). 8 down-regulated proteins were initially elevated above thresholds associated with enhanced CV risk in the literature (myeloperoxidase, C-X-C motif chemokine 10, E-selectin, interleukin-6, cystatin B, von Willebrand factor, tumor necrosis factor receptor 1 and N-terminal prohormone brain natriuretic peptide). Treatment lowered these proteins to below their risk thresholds, except for IL-6, which was lowered but remained at its risk threshold despite successful psoriasis skin treatment. In summary, 12 weeks of ustekinumab treatment reduced serum proteins present at levels associated with CV risk in psoriasis patients. Further studies can evaluate these proteins as potential ustekinumab-modulated biomarkers of CV risk in psoriasis and the impact of ustekinumab on CV risk reduction., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Psoriasis vulgaris is a common inflammatory disease affecting 7.5 million adults just in the US. Previously, psoriasis immunopathogenesis has been viewed as the imbalance between CD4 + T-helper 17 (Th17) cells and regulatory T-cells (Tregs). However, current paradigms are rapidly evolving as new technologies to study immune cell subsets in the skin have been advanced. For example, recently minted single-cell RNA sequencing technology has provided the opportunity to compare highly differing transcriptomes of Type 17 T-cell (T17 cell) subsets depending on IL-17A vs . IL-17F expression. The expression of regulatory cytokines in T17 cell subsets provided evidence of T-cell plasticity between T17 cells and regulatory T-cells (Tregs) in humans. In addition to Tregs, other types of regulatory cells in the skin have been elucidated, including type 1 regulatory T-cells (Tr1 cells) and regulatory dendritic cells. More recently, investigators are attempting to apply single-cell technologies to clinical trials of biologics to test if monoclonal blockade of pathogenic T-cells will induce expansion of regulatory immune cell subsets involved in skin homeostasis., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kim, Moreno and Krueger.)

Competing Interests: None disclosed.

Background: Hidradenitis suppurativa (HS) is an inflammatory skin disease with dysregulation of the interleukin (IL)-17 axis. Recently, we reported the clinical benefit of brodalumab, a human anti-IL-17 receptor A (IL-17RA) monoclonal antibody, in moderate-to-severe HS., Objectives: To characterize the molecular response to brodalumab in HS skin and serum, and to identify biomarkers of treatment response., Methods: Ten participants, who received brodalumab 210 mg /1·5 mL subcutaneously at weeks 0, 1, 2, 4 and every 2 weeks thereafter, were included in this molecular profiling study (NCT03960268). RNA sequencing and immunohistochemistry of nonlesional, perilesional and lesional HS skin biopsies, and Olink high-throughput proteomics of serum at baseline, weeks 4 and 12 were assessed., Results: At week 12, brodalumab led to a decrease of overall inflammation, and improvement of psoriasis-, keratinocyte- and neutrophil-related pathways. Despite perilesional and lesional skin exhibiting no differentially expressed genes at baseline, treatment response was best assessed in perilesional skin. In serum, brodalumab treatment decreased pathways involved in neutrophil inflammation. Patients with higher baseline expression of neutrophil-associated lipocalin-2 (LCN2) in the skin or IL-17A in the serum demonstrated greater decreases of HS-related inflammatory cytokines as measured in skin biopsies at week 12., Conclusions: IL-17RA inhibition by brodalumab decreases several pathogenic inflammatory axes in HS. Perilesional skin provides a valid and robust assessment of treatment response. Expression of LCN2 in skin or IL-17A in serum may be used as biomarkers to stratify patients that may have a superior molecular response to brodalumab., (© 2022 British Association of Dermatologists.)

Background: Psoriasis, a chronic inflammatory disease dependent on the IL-23/T H 17 pathway, is initiated through plasmacytoid dendritic cell activation and type I IFN induction in the skin. Deucravacitinib, a selective tyrosine kinase 2 (TYK2) inhibitor, blocks IL-23, IL-12, and type I IFN signaling in cellular assays., Objective: We investigated changes in IL-23/T H 17 and type I IFN pathway biomarkers and gene responses as well as measures of selectivity for TYK2 over Janus kinases (JAKs) 1-3 in patients with moderate to severe psoriasis receiving deucravacitinib., Methods: Deucravacitinib was evaluated in a randomized, placebo-controlled, dose-ranging trial. Biopsy samples from nonlesional (day 1) and lesional skin (days 1, 15, and 85) were assessed for changes in IL-23/IL-12 and type I IFN pathway biomarkers by quantitative reverse-transcription polymerase chain reaction, RNA sequencing, and immunohistochemistry. Laboratory markers were measured in blood. Percentage change from baseline in Psoriasis Area and Severity Index (PASI) score was assessed., Results: IL-23 pathway biomarkers in lesional skin returned toward nonlesional levels dose-dependently with deucravacitinib. IFN and IL-12 pathway genes were normalized. Markers of keratinocyte dysregulation, keratin-16, and β-defensin genes approached nonlesional levels with effective doses. Select laboratory parameters affected by JAK1-3 inhibition were not affected by deucravacitinib. Greater improvements in PASI scores, correlated with biomarker changes, were seen with the highest doses of deucravacitinib versus lower doses or placebo., Conclusion: Robust clinical efficacy with deucravacitinib treatment was associated with decreases in IL-23/T H 17 and IFN pathway biomarkers. The lack of effect seen on biomarkers specific to JAK1-3 inhibition supports selectivity of deucravacitinib for TYK2; larger confirmatory studies are needed., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)