Multiple environmental antigens may trigger autoimmunity in psoriasis through T-cell receptor polyspecificity.

Introduction: Psoriasis is a T-cell mediated autoimmune skin disease. HLA-C*06:02 is the main psoriasis-specific risk gene. Using a Vα3S1/Vß13S1 T-cell receptor (TCR) from a lesional psoriatic CD8+ T-cell clone we had discovered that, as an underlying pathomechanism, HLA-C*06:02 mediates an autoimmune response against melanocytes in psoriasis, and we had identified an epitope from ADAMTS-like protein 5 (ADAMTSL5) as a melanocyte autoantigen. The conditions activating the psoriatic autoimmune response in genetically predisposed individuals throughout life remain incompletely understood. Here, we aimed to identify environmental antigens that might trigger autoimmunity in psoriasis because of TCR polyspecificity. Methods: We screened databases with the peptide recognition motif of the Vα3S1/Vß13S1 TCR for environmental proteins containing peptides activating this TCR. We investigated the immunogenicity of these peptides for psoriasis patients and healthy controls by lymphocyte stimulation experiments and peptide-loaded HLA-C*06:02 tetramers. Results: We identified peptides from wheat, Saccharomyces cerevisiae, microbiota, tobacco, and pathogens that activated both the Vα3S1/Vß13S1 TCR and CD8+ T cells from psoriasis patients. Using fluorescent HLA-C*06:02 tetramers loaded with ADAMTSL5 or wheat peptides, we find that the same CD8+ T cells may recognize both autoantigen and environmental antigens. A wheat-free diet could alleviate psoriasis in several patients. Discussion: Our results show that due to TCR polyspecificity, several environmental antigens corresponding to previously suspected psoriasis risk conditions converge in the reactivity of a pathogenic psoriatic TCR and might thus be able to stimulate the psoriatic autoimmune response against melanocytes. Avoiding the corresponding environmental risk factors could contribute to the management of psoriasis.

EULAR study group on 'MHC-I-opathy': identifying disease-overarching mechanisms across disciplines and borders.

The 'MHC-I (major histocompatibility complex class I)-opathy' concept describes a family of inflammatory conditions with overlapping clinical manifestations and a strong genetic link to the MHC-I antigen presentation pathway. Classical MHC-I-opathies such as spondyloarthritis, Behçet's disease, psoriasis and birdshot uveitis are widely recognised for their strong association with certain MHC-I alleles and gene variants of the antigen processing aminopeptidases ERAP1 and ERAP2 that implicates altered MHC-I peptide presentation to CD8+T cells in the pathogenesis. Progress in understanding the cause and treatment of these disorders is hampered by patient phenotypic heterogeneity and lack of systematic investigation of the MHC-I pathway.Here, we discuss new insights into the biology of MHC-I-opathies that strongly advocate for disease-overarching and integrated molecular and clinical investigation to decipher underlying disease mechanisms. Because this requires transformative multidisciplinary collaboration, we introduce the EULAR study group on MHC-I-opathies to unite clinical expertise in rheumatology, dermatology and ophthalmology, with fundamental and translational researchers from multiple disciplines such as immunology, genomics and proteomics, alongside patient partners. We prioritise standardisation of disease phenotypes and scientific nomenclature and propose interdisciplinary genetic and translational studies to exploit emerging therapeutic strategies to understand MHC-I-mediated disease mechanisms. These collaborative efforts are required to address outstanding questions in the etiopathogenesis of MHC-I-opathies towards improving patient treatment and prognostication.

Generalized pustular psoriasis: A global Delphi consensus on clinical course, diagnosis, treatment goals and disease management.

BACKGROUND: Generalized pustular psoriasis (GPP) is a rare and highly heterogeneous skin disease, characterized by flares of neutrophilic pustules and erythema. As a rare disease with few clinical studies and no standardized management approaches, there is a paucity of knowledge regarding GPP. OBJECTIVES: Conduct a Delphi panel study to identify current evidence and gain advanced insights into GPP. METHODS: A systematic literature review was used to identify published literature and develop statements categorized into four key domains: clinical course and flare definition; diagnosis; treatment goals; and holistic management. Statements were rated on a Likert scale by a panel of dermatologists in two rounds of online questionnaires; the threshold for consensus was agreement by ≥80%. RESULTS: Twenty-one panellists reached consensus on 70.9%, 61.8%, 100.0% and 81.8% of statements in the 'clinical course and flare definition', 'diagnosis', 'treatment goals' and 'holistic management of GPP' domains, respectively. There was clear consensus on GPP being phenotypically, genetically and immunologically distinct from plaque psoriasis. Clinical course is highly variable, with an extensive range of complications. Clinical and histologic features supporting GPP diagnosis reached high levels of agreement, and although laboratory evaluations were considered helpful for diagnosis and monitoring disease severity, there was uncertainty around the value of individual tests. All acute and long-term treatment goals reached consensus, including rapid and sustained clearance of pustules, erythema, scaling and crust, clearance of skin lesions and prevention of new flares. Potential triggers, associated comorbidities and differential diagnoses achieved low rates of consensus, indicating that further evidence is needed. CONCLUSIONS: Global consensus between dermatologists was reached on clinically meaningful goals for GPP treatment, on key features of GPP flares and on approaches for assessing disease severity and multidisciplinary management of patients. On this basis, we present a management algorithm for patients with GPP for use in clinical practice.

Spesolimab improves patient-reported outcomes in patients with generalized pustular psoriasis: Results from the Effisayil 1 study.

BACKGROUND: Generalized pustular psoriasis (GPP) is a rare inflammatory skin disease with a considerable clinical burden. In the Effisayil™ 1 study, spesolimab, an anti-interleukin-36 receptor monoclonal antibody, demonstrated efficacy in treating GPP flares. OBJECTIVES: To evaluate patient-reported outcomes (PROs) of patients with GPP who were treated with intravenous (IV) spesolimab 900 mg in the Effisayil™ 1 study. METHODS: Fifty-three patients presenting with a GPP flare were randomized (2:1) to receive a single dose of IV spesolimab 900 mg or placebo and were followed for 12 weeks. Four PROs (pain visual analogue scale [pain VAS]; Functional Assessment of Chronic Illness Therapy-Fatigue [FACIT-Fatigue]; Dermatology Life Quality Index [DLQI]; and Psoriasis Symptom Scale [PSS]) were assessed throughout the 12-week study. Minimal clinically important differences (MCIDs) were defined. All data are reported descriptively. RESULTS: In patients who received spesolimab, improvements from baseline (median [Q1, Q3]) were observed in pain VAS (-21.3 [-55.3, -3.1]), FACIT-Fatigue (7.0 [1.0, 20.0]), DLQI (-2.5 [-8.0, 1.0]) and PSS (-4.0 [-7.0, 0.0]) within 1 week of treatment. These improvements were sustained over 12 weeks and corresponded to the achievement of MCIDs at Week 1, which were also sustained over 12 weeks. Patients in the placebo arm experienced improvements in PROs and achievement of MCIDs after receipt of open-label spesolimab at Week 1. CONCLUSIONS: Patients with a GPP flare treated with spesolimab achieved improvements in PROs by Week 1, which were sustained for 12 weeks, and achieved MCIDs as early as Week 1.

Prevalence, comorbidities and mortality of generalized pustular psoriasis: A literature review.

Generalized pustular psoriasis (GPP) is a rare auto-inflammatory skin disease characterised by acute episodes of sterile pustule formation. Diagnosis and treatment of the disease have historically been complicated by a lack of awareness, and no consistent global definition or clinical coding standards. Now acknowledged as a distinct clinical entity with a recognised genetic component, GPP can take a serious and life-threatening course due to systemic inflammatory complications and its association with various comorbidities. As with other rare diseases, there are significant challenges to understanding the epidemiology of GPP, notably a small patient population, non-standardised study methodologies and ethnic differences in its presentation. A clearer understanding of GPP is therefore required for clinicians to better manage patients with this rare condition. In this review article, we present an overview of the available data on GPP prevalence estimates in key demographics and report the frequency of genetic mutations associated with the disease. We detail the incidence of known comorbidities and summarise the data on mortality and assigned causes of death. Lastly, we discuss the various factors that impact the collection, interpretation and comparison of these data.

ERAP1 Controls the Autoimmune Response against Melanocytes in Psoriasis by Generating the Melanocyte Autoantigen and Regulating Its Amount for HLA-C*06:02 Presentation.

Autoimmune diseases develop when autoantigens activate previously quiescent self-reactive lymphocytes. Gene-gene interaction between certain HLA class I risk alleles and variants of the endoplasmic reticulum aminopeptidase ERAP1 controls the risk for common immune-mediated diseases, including psoriasis, ankylosing spondylitis, and Behçet disease. The functional mechanisms underlying this statistical association are unknown. In psoriasis, HLA-C*06:02 mediates an autoimmune response against melanocytes by autoantigen presentation. Using various genetically modified cell lines together with an autoreactive psoriatic TCR in a TCR activation assay, we demonstrate in this study that in psoriasis, ERAP1 generates the causative melanocyte autoantigen through trimming N-terminal elongated peptide precursors to the appropriate length for presentation by HLA-C*06:02. An ERAP1 risk haplotype for psoriasis produced the autoantigen much more efficiently and increased HLA-C expression and stimulation of the psoriatic TCR by melanocytes significantly more than a protective haplotype. Compared with the overall HLA class I molecules, cell surface expression of HLA-C decreased significantly more upon ERAP1 knockout. The combined upregulation of ERAP1 and HLA-C on melanocytes in psoriasis lesions emphasizes the pathogenic relevance of their interaction in patients. We conclude that in psoriasis pathogenesis, the increased generation of an ERAP1-dependent autoantigen by an ERAP1 risk haplotype enhances the likelihood that autoantigen presentation by HLA-C*06:02 will exceed the threshold for activation of potentially autoreactive T cells, thereby triggering CD8+ T cell-mediated autoimmune disease. These data identify ERAP1 function as a central checkpoint and promising therapeutic target in psoriasis and possibly other HLA class I-associated diseases with a similar genetic predisposition.

Myeloperoxidase Modulates Inflammation in Generalized Pustular Psoriasis and Additional Rare Pustular Skin Diseases.

Generalized pustular psoriasis (GPP) is a severe multi-systemic inflammatory disease characterized by neutrophilic pustulosis and triggered by pro-inflammatory IL-36 cytokines in skin. While 19%-41% of affected individuals harbor bi-allelic mutations in IL36RN, the genetic cause is not known in most cases. To identify and characterize new pathways involved in the pathogenesis of GPP, we performed whole-exome sequencing in 31 individuals with GPP and demonstrated effects of mutations in MPO encoding the neutrophilic enzyme myeloperoxidase (MPO). We discovered eight MPO mutations resulting in MPO -deficiency in neutrophils and monocytes. MPO mutations, primarily those resulting in complete MPO deficiency, cumulatively associated with GPP (p = 1.85E-08; OR = 6.47). The number of mutant MPO alleles significantly differed between 82 affected individuals and >4,900 control subjects (p = 1.04E-09); this effect was stronger when including IL36RN mutations (1.48E-13) and correlated with a younger age of onset (p = 0.0018). The activity of four proteases, previously implicated as activating enzymes of IL-36 precursors, correlated with MPO deficiency. Phorbol-myristate-acetate-induced formation of neutrophil extracellular traps (NETs) was reduced in affected cells (p = 0.015), and phagocytosis assays in MPO-deficient mice and human cells revealed altered neutrophil function and impaired clearance of neutrophils by monocytes (efferocytosis) allowing prolonged neutrophil persistence in inflammatory skin. MPO mutations contribute significantly to GPP's pathogenesis. We implicate MPO as an inflammatory modulator in humans that regulates protease activity and NET formation and modifies efferocytosis. Our findings indicate possible implications for the application of MPO inhibitors in cardiovascular diseases. MPO and affected pathways represent attractive targets for inducing resolution of inflammation in neutrophil-mediated skin diseases.

The Woronoff Ring in Psoriasis and the Mechanisms of Postinflammatory Hypopigmentation.

The Woronoff ring is a ring-like hypopigmentation zone around regressing psoriasis lesions. Although it was first described more than 100 years ago, its aetiology has remained a mystery. Recent insights into the pathogenesis of psoriasis can now explain the origin of the Woronoff ring. Psoriasis involves an HLA-class I-restricted autoimmune response of CD8+ T cells against melanocytes in the epidermis. The pathogenic CD8+ T cells are not cytotoxic, but are characterized by the production of interleukin-17, interleukin-22 and tumour necrosis factor-α. Interleukin-17 and tumour necrosis factor-α act synergistically on melanocytes by increasing proliferation while inhibiting melanogenesis. This reduces the cellular melanin content despite an increased number of melanocytes in psoriatic lesions. As a consequence, during healing the prior influence of interleukin-17 and tumour necrosis factor-α, despite the increased density of melanocytes, leaves a hypopigmented zone at the edge of regressing psoriasis lesions, which becomes visible as the Woronoff ring. This mechanism can explain a long-discussed puzzling phenomenon in dermatology.

Clonality of CD4+ Blood T Cells Predicts Longer Survival With CTLA4 or PD-1 Checkpoint Inhibition in Advanced Melanoma.

Recognition of cancer antigens drives the clonal expansion of cancer-reactive T cells, which is thought to contribute to restricted T-cell receptor (TCR) repertoires in tumor-infiltrating lymphocytes (TILs). To understand how tumors escape anti-tumor immunity, we investigated tumor-associated T-cell repertoires of patients with advanced melanoma and after blockade of the cytotoxic T-lymphocyte-associated protein 4 (CTLA4) or programmed cell death 1 (PD-1). TCR Vß-gene spectratyping allowed us to quantify restrictions of T-cell repertoires and, further, diversities of T-cell clones. In this study, we show that the blood TCR repertoires were variably restricted in CD4+ and extensively restricted in CD8+ T cells of patients with advanced melanoma, and contained clones in both T-cell fractions prior to the start of immunotherapy. A greater diversification especially of CD4+ blood T-cell clones before immunotherapy showed statistically significant correlations with long-term survival upon CTLA4 or PD-1 inhibition. Analysis of TILs and corresponding blood available in one patient indicated that blood clonality may at least partially be related to the clonal expansion in the tumor microenvironment. In patients who developed severe immune-related adverse events (IrAEs), CD4+ and CD8+ TCR spectratypes became more restricted during anti-CTLA4 treatment, suggesting that newly expanded oligoclonal T-cell responses may contribute to IrAEs. This study reveals diverse T-cell clones in the blood of melanoma patients prior to immunotherapy, which may reflect the extent to which T cells are able to react against melanoma and potentially control melanoma progression. Therefore, the T-cell clonality in the circulation may have predictive value for antitumor responses from checkpoint inhibition.

Simultaneous Response in Several Domains in Patients with Psoriatic Disease Treated with Etanercept as Monotherapy or in Combination with Conventional Synthetic Disease-modifying Antirheumatic Drugs.

OBJECTIVE: To evaluate patients with psoriatic arthritis (PsA) receiving etanercept (ETN) monotherapy or ETN plus conventional synthetic disease-modifying antirheumatic drugs (csDMARD) to determine the proportion achieving a clinically meaningful response in arthritis, psoriasis, and quality of life simultaneously. METHODS: A prospective, multicenter, 52-week observational study in patients with active PsA evaluated treatment with ETN in clinical practice (ClinicalTrials.gov: NCT00293722). This analysis assessed simultaneous achievement of 3 treatment targets: low disease activity (LDA) based on 28-joint count Disease Activity Score (DAS28); body surface area (BSA) involvement ≤ 3%; and a score > 45 on the Medical Outcomes Study Short Form-12 (SF-12) physical component summary. RESULTS: Of 579 patients, 380 received ETN monotherapy and 199 received combination ETN plus csDMARD. At 52 weeks, data for all 3 disease domains were available for 251 patients receiving monotherapy and 151 receiving combination therapy. In the monotherapy and combination therapy groups, 61 (24.3%) and 37 (24.5%) patients, respectively, achieved all 3 treatment targets simultaneously. A significantly greater proportion of patients receiving monotherapy versus combination therapy achieved SF-12 > 45 (43.0% vs 31.8%; p < 0.05) and DAS28 LDA (72.5% vs 62.3%; p < 0.05). Conversely, BSA ≤ 3% was reached by a significantly greater proportion receiving combination therapy (75.5% vs 56.6%; p < 0.001). However, baseline BSA involvement was higher for the monotherapy group. CONCLUSION: While nearly half the patients achieved arthritis and psoriasis treatment targets simultaneously and one-fourth reached all 3 treatment targets, combining ETN and csDMARD did not substantially improve clinical response compared with ETN monotherapy in this real-world PsA patient population.

Unopposed IL-36 Activity Promotes Clonal CD4+ T-Cell Responses with IL-17A Production in Generalized Pustular Psoriasis.

Generalized pustular psoriasis (GPP) is the most severe psoriasis variant. Mutations in the IL-36 antagonist IL36RN, in CARD14 or AP1S3 provide genetic evidence for autoinflammatory etiology but cannot explain its pathogenesis completely. Here we demonstrate that unopposed IL-36 signaling promotes antigen-driven and likely pathogenic T-helper type 17 (Th17) responses in GPP. We observed that CD4+ T cells in blood and skin lesions of GPP patients were characterized by intense hyperproliferation, production of the GPP key mediator, IL-17A, and highly restricted TCR repertoires with identical T-cell clones in blood and skin lesions, indicating antigen-driven T-cell expansions. The clonally expanded CD4+ T cells were major producers of IL-17A. IL-36 signaling substantially enhanced TCR-mediated proliferation of CD4+ T cells. Moreover, GPP patients showed preferences for HLA-DRB1∗14, HLA-DQB1∗05, and HLA-DQB1∗03. We conclude that in GPP unopposed IL-36 signaling and certain HLA-class II alleles may cooperate in promoting antigen-driven Th17 responses, which in the obvious absence of exogenous triggers may reflect autoimmune reactions. This study reveals a pathogenic pathway where innate immune dysregulation promotes T-cell-mediated inflammation in GPP.

Secukinumab Self-Administration by Prefilled Syringe Maintains Reduction of Plaque Psoriasis Severity Over 52 Weeks: Results of the FEATURE Trial.

BACKGROUND: Secukinumab, a human monoclonal antibody that selectively targets interleukin-17A, is highly efficacious in the treatment of moderate-to-severe psoriasis, starting at early time points, with a sustained effect and a favorable safety profile. METHODS: Patients with moderate-to-severe plaque psoriasis were randomized to secukinumab 300 mg, secukinumab 150 mg, or placebo self-administered by prefilled syringe at baseline, weeks 1, 2, and 3, and then every four weeks from week 4 to 48. Efficacy responses (≥ 75/90/100% improvement in Psoriasis Area and Severity Index [PASI 75/90/100] and clear/almost clear skin by Investigator's Global Assessment 2011 modified version [IGA mod 2011 0/1]) were measured to week 52. Patient-reported usability of the prefilled syringe was evaluated by the Self-Injection Assessment Questionnaire to week 48. RESULTS: The efficacy of secukinumab increased to week 16 and was maintained to week 52. With secukinumab 300 mg at week 52, PASI 75/90/100 and IGA mod 2011 0/1 responses were achieved by 83.5%/68.0%/47.5% and 71.5% of patients when analyzed by multiple imputation, respectively, and by 75.9%/62.1%/43.1% and 63.8% of patients when analyzed by nonresponder imputation, respectively. With secukinumab 150 mg at week 52, PASI 75/90/100 and IGA mod 2011 0/1 responses were achieved by 63.5%/50.3%/31.1% and 43.6% of patients when analyzed by multiple imputation, respectively, and by 61.0%/49.2%/30.5% and 42.4% of patients when analyzed by nonresponder imputation, respectively. Self-reported acceptability of the prefilled syringe was high throughout the study. The incidence of adverse events (AE) was well balanced between groups, with AEs reported in 74.4% of patients receiving secukinumab 300 mg and 77.3% of patients receiving secukinumab 150 mg. Nasopharyngitis was the most common AE across both secukinumab groups. CONCLUSION: Self-administration of secukinumab by prefilled syringe was associated with robust and sustained efficacy and a favorable safety profile up to week 52.

J Drugs Dermatol. 2016;15(10):1226-1234.

CTLA4 as Immunological Checkpoint in the Development of Multiple Sclerosis.

We investigated a patient who developed multiple sclerosis (MS) during treatment with the CTLA4-blocking antibody ipilimumab for metastatic melanoma. Initially he showed subclinical magnetic resonance imaging (MRI) changes (radiologically isolated syndrome). Two courses of ipilimumab were each followed by a clinical episode of MS, 1 of which was accompanied by a massive increase of MRI activity. Brain biopsy confirmed active, T-cell type MS. Quantitative next generation sequencing of T-cell receptor genes revealed distinct oligoclonal CD4(+) and CD8(+) T-cell repertoires in the primary melanoma and cerebrospinal fluid. Our results pinpoint the coinhibitory molecule CTLA4 as an immunological checkpoint and therapeutic target in MS. Ann Neurol 2016;80:294-300.

Therapeutic Efficacy of Interleukin 12/Interleukin 23 Blockade in Generalized Pustular Psoriasis Regardless of IL36RN Mutation Status.

IMPORTANCE: Generalized pustular psoriasis von Zumbusch type (GPP) is the most severe manifestation of psoriasis. The etiology of GPP is only partially understood, and GPP lacks approved treatments. Loss-of-function mutations in the interleukin 36 (IL-36) receptor antagonist (IL36RN), an inhibitor of innate immune activation in the skin, and therapeutic efficacy of IL-1 blockade in a subset of patients with GPP are viewed as evidence for an autoinflammatory pathogenesis. A pathogenic role of T cells has not been considered. OBJECTIVE: To test whether ustekinumab, a monoclonal antibody blocking IL-12 and IL-23, is an effective treatment modality for patients in whom GPP treatment with conventional psoriasis drugs or antagonists of tumor necrosis factor (TNF) has not been sufficiently effective, is contraindicated, or has lost efficacy. DESIGN, SETTING, AND PARTICIPANTS: We treated a series of 4 patients with GPP with ustekinumab, which was applied on an outpatient basis according to the dosing regimen approved for psoriasis vulgaris. In 3 patients it was combined with low doses of the retinoid acitretin. IL36RN mutations were determined in all 4 patients by means of targeted sequencing of genomic DNA. MAIN OUTCOME MEASURES: The response to therapy was assessed by clinical examination. RESULTS: The 4 patients were female. Sequencing of IL36RN identified a homozygous mutation in case 1 (Pro76Leu). The other 3 patients carried no rare IL36RN variants. Overall GPP duration ranged from 50 to 146 months. Ustekinumab treatment is currently ongoing in all 4 patients without loss of efficacy, currently reaching treatment durations of 17 (case 1) to 44 months (case 3). Ustekinumab treatment induced sustained remissions in all 4 GPP patients. This response was independent of IL36RN mutations and consolidated by combination with low doses of the retinoid acitretin. CONCLUSIONS AND RELEVANCE: Ustekinumab-induced remissions suggest that T cells play a crucial role in GPP pathogenesis based on the documented role that IL-12 and IL-23 play in autoimmune diseases through differentiating helper T cell 1 (TH1) and maintaining TH17 responses. Acitretin treatment may support ustekinumab efficacy, possibly by suppressing TH17 responses through the retinoid-related orphan receptors, RORγt and RORα. Combining IL-12/IL-23 blockade and acitretin may constitute an efficient treatment modality interfering with GPP pathomechanisms.

Lichen planus of the lower limbs: successful treatment with psoralen cream plus ultraviolet A photochemotherapy.

Lichen planus (LP) classifies into different subtypes depending on morphology and localization. Localized LP of the lower limb (LPLL) manifests a great challenge due to persistent itching, therapeutic resistance and the risk to develop into SCC. We report two cases with LPLL refractory to standard topical therapy, which were successfully treated with psoralen cream plus UVA photochemotherapy (cream-PUVA). We propose cream-PUVA as an alternative therapeutic option effective for localized LP of the lower limbs.