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.

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.

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.

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.

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.

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.

A Phase 2 Trial of Guselkumab versus Adalimumab for Plaque Psoriasis.

BACKGROUND: Little is known about the effect of specific anti-interleukin-23 therapy, as compared with established anti-tumor necrosis factor therapies, for the treatment of moderate-to-severe plaque psoriasis. METHODS: In a 52-week, phase 2, dose-ranging, randomized, double-blind, placebo-controlled, active-comparator trial, we compared guselkumab (CNTO 1959), an anti-interleukin-23 monoclonal antibody, with adalimumab in patients with moderate-to-severe plaque psoriasis. A total of 293 patients were randomly assigned to receive guselkumab (5 mg at weeks 0 and 4 and every 12 weeks thereafter, 15 mg every 8 weeks, 50 mg at weeks 0 and 4 and every 12 weeks thereafter, 100 mg every 8 weeks, or 200 mg at weeks 0 and 4 and every 12 weeks thereafter) through week 40, placebo, or adalimumab (standard dosage for psoriasis). At week 16, patients in the placebo group crossed over to receive guselkumab at a dose of 100 mg every 8 weeks. The primary end point was the proportion of patients with a Physician's Global Assessment (PGA) score of 0 (indicating cleared psoriasis) or 1 (indicating minimal psoriasis) at week 16. RESULTS: At week 16, the proportion of patients with a PGA score of 0 or 1 was significantly higher in each guselkumab group than in the placebo group: 34% in the 5-mg group, 61% in the 15-mg group, 79% in the 50-mg group, 86% in the 100-mg group, and 83% in the 200-mg group, as compared with 7% in the placebo group (P≤0.002 for all comparisons). Moreover, the proportion was significantly higher in the 50-mg, 100-mg, and 200-mg guselkumab groups than in the adalimumab group (58%) (P<0.05 for all comparisons). At week 16, the proportion of patients with at least a 75% improvement in Psoriasis Area and Severity Index scores was significantly higher in each guselkumab group than in the placebo group (P<0.001 for all comparisons). At week 40, the proportion of patients with a PGA score of 0 or 1 remained significantly higher in the 50-mg, 100-mg, and 200-mg guselkumab groups than in the adalimumab group (71%, 77%, and 81%, respectively, vs. 49%) (P<0.05 for all comparisons). Between week 0 and week 16, infections were observed in 20% of the patients in the guselkumab groups, 12% in the adalimumab group, and 14% in the placebo group. CONCLUSIONS: The results of this phase 2 trial suggest that guselkumab may be an effective therapy for plaque psoriasis and that control of psoriasis can be achieved with specific anti-interleukin-23 therapy. (Funded by Janssen Research and Development; X-PLORE ClinicalTrials.gov number, NCT01483599.).

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.

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.

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.

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.

International Consensus Definition and Diagnostic Criteria for Generalized Pustular Psoriasis From the International Psoriasis Council.

Importance: Generalized pustular psoriasis (GPP) lacks internationally accepted definitions and diagnostic criteria, impeding timely diagnosis and treatment and hindering cross-regional clinical and epidemiological study comparisons. Objective: To develop an international consensus definition and diagnostic criteria for GPP using the modified Delphi method. Evidence Review: The rarity of GPP presents a challenge in acquiring comprehensive published clinical data necessary for developing standardized definition and criteria. Instead of relying on a literature search, 43 statements that comprehensively addressed the fundamental aspects of the definitions and diagnostic criteria for GPP were formulated based on expert reviews of 64 challenging GPP cases. These statements were presented to a panel of 33 global GPP experts for voting, discussion, and refinements in 2 virtual consensus meetings. Consensus during voting was defined as at least 80% agreement; the definition and diagnostic criteria were accepted by all panelists after voting and in-depth discussion. Findings: In the first and second modified Delphi round, 30 (91%) and 25 (76%) experts participated. In the initial Delphi round, consensus was achieved for 53% of the statements, leading to the approval of 23 statements that were utilized to develop the proposed definitions and diagnostic criteria for GPP. During the second Delphi round, the final definition established was, "Generalized Pustular Psoriasis is a systemic inflammatory disease characterized by cutaneous erythema and macroscopically visible sterile pustules." It can occur with or without systemic symptoms, other psoriasis types, and laboratory abnormalities. GPP may manifest as an acute form with widespread pustules or a subacute variant with an annular phenotype. The identified essential criterion was, "Macroscopically visible sterile pustules on erythematous base and not restricted to the acral region or within psoriatic plaques." Conclusions and Relevance: The achievement of international consensus on the definition and diagnostic criteria for GPP underscores the importance of collaboration, innovative methodology, and expert engagement to address rare diseases. Although further validation is needed, these criteria can serve as a reference point for clinicians, researchers, and patients, which may contribute to more accurate diagnosis and improved management of GPP.

Long-term safety experience of ustekinumab in patients with moderate-to-severe psoriasis (Part I of II): results from analyses of general safety parameters from pooled Phase 2 and 3 clinical trials.

BACKGROUND: Ustekinumab targets interleukin (IL)-12 and IL-23 in the treatment of moderate-to-severe psoriasis. OBJECTIVE: To evaluate overall pooled study data to assess the safety profile of ustekinumab through 3 years of treatment. METHODS: Cumulative safety data were pooled from studies in 3117 ustekinumab-treated patients. RESULTS: During the placebo-controlled periods (Phase 2, PHOENIX 1, PHOENIX 2), rates of adverse events (AEs) were comparable among patients treated with placebo (50.4%), with ustekinumab 45 mg (57.6%), or with ustekinumab 90 mg (51.6%); similar findings were observed during the controlled period of the ACCEPT trial (etanercept: 70.0%; ustekinumab 45 mg: 66.0%; and ustekinumab 90 mg: 69.2%). Rates of serious AEs (SAEs) through the controlled periods were low and comparable among all groups (1.2% to 1.9%). Through 3 years, rates of AEs per 100 patient-years of follow-up (/100 patient-yrs) (45 mg: 305.2/100 patient-yrs; 90 mg: 305.9/100 patient-yrs) and SAEs (45 mg: 6.8/100 patient-yrs; 90 mg: 8.2/100 patient-yrs) were comparable between ustekinumab doses. No cases of demyelination or tuberculosis were reported in these trials. No dose response in rates of AEs, overall infections, or SAEs was apparent through 3 years. Rates of AEs, infections, SAEs, and AEs leading to study agent discontinuation remained generally stable or decreased over time. LIMITATIONS: Controlled periods did not extend beyond 12 to 20 weeks. Only 1247 of the 3117 ustekinumab-treated patients were treated for 2 or more years. CONCLUSIONS: The safety profile of continued ustekinumab exposure through up to 3 years is favorable and consistent with previous short-term reports.