Measuring Psoriasis Severity at Home.

Psoriasis plaque severity metrics, such as induration (thickness), erythema (redness), and desquamation (scaliness), are associated with the subsequent development of psoriatic arthritis (PsA) among cutaneous-only psoriasis patients (patients with skin or nail psoriasis but no psoriatic arthritis). These metrics can be used for PsA screening. However, a key challenge in PsA screening is to optimize accessibility and minimize costs for patients, while also reducing the burden on healthcare systems. Therefore, an ideal screening tool consists of questions that patients can answer without a physician's assistance. Although reference images can be used to help a patient self-assess erythema and desquamation severity, a patient would need a tactile induration reference card to self-assess induration severity. This protocol describes how to create an induration reference card, the Psoriasis Thickness Reference Card, as well as how to use it to assess lesion induration severity. Administration of reference images for erythema and desquamation and a Psoriasis Thickness Reference Card for induration to 27 psoriasis patients showed that patients were moderately successful at self-assessing the severity of these three metrics. These findings support the feasibility of a future PsA screening test that patients can complete without the need for physician assistance.

PAPRIKA: A Question Bank for Assessing Psoriatic Arthritis Risk in Individuals of Diverse Ancestries.

OBJECTIVE: We aimed to create a question bank about clinical factors for predicting the diagnoses of psoriatic arthritis in patients with psoriasis of various ancestries and skin tones, which can be completed entirely by patients. METHODS: Utah Psoriasis Initiative participants without a psoriatic arthritis diagnosis at enrollment were observed for diagnosis during the study period. We inferred ancestry from exome sequencing data and performed Cox proportional hazards regression to identify clinical predictors of psoriatic arthritis in different ancestry groups. Based on results and literature review, we developed a question bank for assessing psoriatic arthritis risk among patients with psoriasis in various ancestries. RESULTS: Patient-reported untreated psoriasis induration and history of fingernail psoriasis were associated with psoriatic arthritis in participants of European and non-European ancestry. We developed the Psoriatic Arthritis Prediction and Identification Question Bank for Diverse Ancestries (PAPRIKA) version 1.0, which included questions regarding psoriasis characteristics, arthritis symptoms, comorbidities, family history, and demographics. PAPRIKA is accessible at http://bjfenglab.org/. CONCLUSION: The clinical features (untreated psoriasis induration and history of fingernail psoriasis) that can predict psoriatic arthritis in European individuals also work for non-European individuals. PAPRIKA can be used to gather psoriatic arthritis predictive data from patients with psoriasis without provider assistance and is relevant for patients across ancestries.

Effect of Costimulatory Blockade With Abatacept After Ustekinumab Withdrawal in Patients With Moderate to Severe Plaque Psoriasis: The PAUSE Randomized Clinical Trial.

IMPORTANCE: Psoriasis relapse may involve compensatory T-cell activation pathways in the presence of CD28-CD80/CD86 blockade with abatacept. OBJECTIVE: To determine whether costimulatory signaling blockade with abatacept prevents psoriasis relapse after ustekinumab withdrawal. DESIGN, SETTING, AND PARTICIPANTS: Psoriasis Treatment with Abatacept and Ustekinumab: a Study of Efficacy (PAUSE), a parallel-design, double-blind, placebo-controlled randomized clinical trial, was conducted at 10 sites in the US and Canada. Participant enrollment opened on March 19, 2014, and concluded on April 11, 2016. Participants were adults with moderate to severe plaque psoriasis and received ustekinumab in a lead-in phase. Those who responded to ustekinumab at week 12 were randomized 1:1 to either the continued with ustekinumab group (ustekinumab group) or the switched to abatacept group (abatacept group). Treatment was discontinued at week 39, and participants were followed up for psoriasis relapse until week 88. Statistical analyses were performed in the intention-to-treat (ITT) and safety samples from May 3, 2018, to July 6, 2021. INTERVENTIONS: Participants received subcutaneous ustekinumab at weeks 0 and 4 (45 mg per dose for those ≤100 kg; 90 mg per dose for those >100 kg). Participants randomized to the abatacept group at week 12 received subcutaneous abatacept, 125 mg weekly, from weeks 12 to 39 and ustekinumab placebo at weeks 16 and 28. Participants randomized to the ustekinumab group received ustekinumab at weeks 16 and 28 and abatacept placebo weekly from weeks 12 to 39. MAIN OUTCOMES AND MEASURES: The primary end point was the proportion of participants with psoriasis relapse (loss of ≥50% of the initial Psoriasis Area and Severity Index improvement) between weeks 12 and 88. Secondary end points included time to psoriasis relapse, proportion of participants with psoriasis relapse between weeks 12 and 40, and adverse events. The psoriasis transcriptome and serum cytokines were evaluated. RESULTS: A total of 108 participants (mean [SD] age, 46.1 [12.1] years; 73 [67.6%] men) were treated with open-label ustekinumab; 91 were randomized to blinded treatment. Similar proportions of participants in the abatacept group and the ustekinumab group relapsed between weeks 12 and 88 (41 of 45 [91.1%] vs 40 of 46 [87.0%]; P = .41). Median time to relapse from the last dose of ustekinumab was similar between groups as well: 36 weeks (95% CI, 36-48 weeks) in the abatacept group vs 32 weeks (95% CI, 28-40 weeks) in the ustekinumab group. Similar numbers and rates of adverse events occurred. Abatacept did not maintain suppression of the pathogenic IL-23-mediated psoriasis molecular signature in lesions after ustekinumab withdrawal, and serum IL-19 levels increased. CONCLUSIONS AND RELEVANCE: This parallel-design, double-blind randomized clinical trial found that abatacept did not prevent psoriasis relapse that occurred after ustekinumab withdrawal because it did not completely block the pathogenic psoriasis molecular pathways that led to relapse. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01999868.

The Proposed PASI-HD Provides More Precise Assessment of Plaque Psoriasis Severity in Anatomical Regions with a Low Area Score.

The Psoriasis Area and Severity Index (PASI) is the most widely used clinical measure in clinical trials to assess disease severity of plaque psoriasis. However, the PASI is not a precise measure of severity with less precision when the regional area of involvement is < 10% of the BSA of a specific anatomical region. Degradation of precision results from the area score defaulting to '1' when the area of involvement within an anatomical region falls between 0% and 10% of the BSA for a given anatomical region. We describe a modification to the PASI, termed PASI-high discrimination (PASI-HD), for determination of more accurate psoriasis severity in body regions where < 10% of the body surface area is affected. The methodology for assessing disease severity in these conditions is described.

Psoriasis Characteristics for the Early Detection of Psoriatic Arthritis.

OBJECTIVE: Delays in the diagnosis and treatment of psoriatic arthritis (PsA) are common. These delays contribute to impairments in quality of life and joint damage. This study aims to calculate the incidence rate of PsA over time and identify clinical features that may be used for PsA prediction in patients with psoriasis (PsO). METHODS: The study population for PsA incidence analysis included 1128 participants enrolled in the Utah Psoriasis Initiative between 2002 and 2014. Clinical evaluation and medical record review were performed to identify new cases of PsA after enrollment. To identify PsO features associated with PsA, the population was restricted to 627 participants who did not have PsA before PsO phenotyping and had been followed up for subsequent PsA diagnosis. We conducted Cox proportional hazard regressions to estimate the HR of PsA associated with PsO characteristics and other health-related features. RESULTS: PsA incidence rate increased for > 60 years following PsO onset (trend P < 0.0001). There was a significant association between PsA and induration severity in untreated lesions (P < 0.001, HR 1.46), history of fingernail involvement (P < 0.001, HR 2.38), pustular PsO (P < 0.001, HR 3.32), fingernail involvement at enrollment (P < 0.001, HR 2.04), and Koebner phenomenon (P < 0.001, HR 1.90). Multivariate analysis yielded a model that included a history of fingernail involvement (P < 0.001, HR 2.16) and untreated induration (P < 0.001, HR 1.41). CONCLUSION: Risk of PsA increases steadily for > 60 years following PsO onset. Patient-reported history of PsO characteristics has greater predictive power than physician-measured features at enrollment visits. The characteristics identified in this study provide guidance for screening for PsA risk in patients with PsO.

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

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

The Physician Global Assessment and Body Surface Area composite tool is a simple alternative to the Psoriasis Area and Severity Index for assessment of psoriasis: post hoc analysis from PRISTINE and PRESTA.

BACKGROUND: The product of Physician Global Assessment and Body Surface Area (PGA × BSA) is a new outcome measure for psoriasis severity and response to therapy. The objective of this study was to evaluate PGA × BSA as an alternative to Psoriasis Area and Severity Index (PASI) for psoriasis assessments. METHODS: The relationship between PASI and PGA × BSA was assessed in a post hoc analysis of pooled data from the PRISTINE (NCT00663052) and PRESTA (NCT00245960) trials in patients with moderate-to-severe psoriasis who received etanercept 50 mg/week. Data were analyzed using Spearman and intra-class correlation coefficients, effect sizes, scatterplots, Bland-Altman plots, and Kappa statistics. RESULTS: Spearman correlations at baseline, week 12, and week 24 were strong for PGA × BSA versus PASI (r=0.78, 0.87, and 0.90, respectively; all P<0.0001) as were intra-class correlations (0.76 [95% confidence interval 0.73-0.80], 0.80 [0.76-0.83], and 0.85 [0.82-0.87], respectively). The effect size was -1.53 for PASI and -0.94 for PGA × BSA (baseline to week 24). Scatterplots and Bland-Altman plots detected a trend across the range of measurement. Kappa statistics (at 12 and 24 weeks) between PASI50/75/90 and 50/75/90% improvement in PGA × BSA showed good agreement (0.58-0.69 at week 12 and 0.63-0.67, respectively; all P<0.0001). At baseline, the Spearman correlation coefficients were 0.96, 0.51, 0.19, and 0.17 for PGA × BSA versus BSA, PGA, Patient Global Assessment, and Dermatology Life Quality Index, respectively (all P<0.001). CONCLUSION: PGA × BSA has advantages over PASI for measuring moderate-to-severe psoriasis; it is intuitive, sensitive, and easy to use.

Genetic signature to provide robust risk assessment of psoriatic arthritis development in psoriasis patients.

Psoriatic arthritis (PsA) is a complex chronic musculoskeletal condition that occurs in ~30% of psoriasis patients. Currently, no systematic strategy is available that utilizes the differences in genetic architecture between PsA and cutaneous-only psoriasis (PsC) to assess PsA risk before symptoms appear. Here, we introduce a computational pipeline for predicting PsA among psoriasis patients using data from six cohorts with >7000 genotyped PsA and PsC patients. We identify 9 new loci for psoriasis or its subtypes and achieve 0.82 area under the receiver operator curve in distinguishing PsA vs. PsC when using 200 genetic markers. Among the top 5% of our PsA prediction we achieve >90% precision with 100% specificity and 16% recall for predicting PsA among psoriatic patients, using conditional inference forest or shrinkage discriminant analysis. Combining statistical and machine-learning techniques, we show that the underlying genetic differences between psoriasis subtypes can be used for individualized subtype risk assessment.

Exome-wide association study reveals novel psoriasis susceptibility locus at TNFSF15 and rare protective alleles in genes contributing to type I IFN signalling.

Psoriasis is a common inflammatory skin disorder for which multiple genetic susceptibility loci have been identified, but few resolved to specific functional variants. In this study, we sought to identify common and rare psoriasis-associated gene-centric variation. Using exome arrays we genotyped four independent cohorts, totalling 11 861 psoriasis cases and 28 610 controls, aggregating the dataset through statistical meta-analysis. Single variant analysis detected a previously unreported risk locus at TNFSF15 (rs6478108; P = 1.50 × 10-8, OR = 1.10), and association of common protein-altering variants at 11 loci previously implicated in psoriasis susceptibility. We validate previous reports of protective low-frequency protein-altering variants within IFIH1 (encoding an innate antiviral receptor) and TYK2 (encoding a Janus kinase), in each case establishing a further series of protective rare variants (minor allele frequency < 0.01) via gene-wide aggregation testing (IFIH1: pburden = 2.53 × 10-7, OR = 0.707; TYK2: pburden = 6.17 × 10-4, OR = 0.744). Both genes play significant roles in type I interferon (IFN) production and signalling. Several of the protective rare and low-frequency variants in IFIH1 and TYK2 disrupt conserved protein domains, highlighting potential mechanisms through which their effect may be exerted.

Large scale meta-analysis characterizes genetic architecture for common psoriasis associated variants.

Psoriasis is a complex disease of skin with a prevalence of about 2%. We conducted the largest meta-analysis of genome-wide association studies (GWAS) for psoriasis to date, including data from eight different Caucasian cohorts, with a combined effective sample size >39,000 individuals. We identified 16 additional psoriasis susceptibility loci achieving genome-wide significance, increasing the number of identified loci to 63 for European-origin individuals. Functional analysis highlighted the roles of interferon signalling and the NFκB cascade, and we showed that the psoriasis signals are enriched in regulatory elements from different T cells (CD8+ T-cells and CD4+ T-cells including TH0, TH1 and TH17). The identified loci explain ∼28% of the genetic heritability and generate a discriminatory genetic risk score (AUC=0.76 in our sample) that is significantly correlated with age at onset (p=2 × 10-89). This study provides a comprehensive layout for the genetic architecture of common variants for psoriasis.

From the Medical Board of the National Psoriasis Foundation: Treatment targets for plaque psoriasis.

BACKGROUND: An urgent need exists in the United States to establish treatment goals in psoriasis. OBJECTIVE: We aim to establish defined treatment targets toward which clinicians and patients with psoriasis can strive to inform treatment decisions, reduce disease burden, and improve outcomes in practice. METHODS: The National Psoriasis Foundation conducted a consensus-building study among psoriasis experts using the Delphi method. The process consisted of: (1) literature review, (2) pre-Delphi question selection and input from general dermatologists and patients, and (3) 4 Delphi rounds. RESULTS: A total of 25 psoriasis experts participated in the Delphi process. The most preferred instrument was body surface area (BSA). The most preferred time for evaluating patient response after starting new therapies was at 3 months. The acceptable response at 3 months postinitiation was either BSA 3% or less or BSA improvement 75% or more from baseline. The target response at 3 months postinitiation was BSA 1% or less. During the maintenance period, evaluation every 6 months was most preferred. The target response at every 6 months maintenance evaluation is BSA 1% or less. LIMITATIONS: Although BSA is feasible in practice, it does not encompass health-related quality of life, costs, and risks of side effects. CONCLUSION: With defined treatment targets, clinicians and patients can regularly evaluate treatment responses and perform benefit-risk assessments of therapeutic options individualized to the patient.

microRNAs in Psoriasis.

Psoriasis is a chronic inflammatory skin condition resulting from a complex interplay among the immune system, keratinocytes, susceptibility genes, and environmental factors. However, the pathogenesis of psoriasis is not completely elucidated. microRNAs represent a promising class of small, noncoding RNA molecules that function to regulate gene expression. Although microRNA research in psoriasis and dermatology is still relatively new, evidence is rapidly accumulating for the role of microRNAs in the pathogenesis of psoriasis and other chronic inflammatory conditions. In this article, we present a comprehensive review of what is known about microRNAs and their role in the pathogenesis of psoriasis.

Desired Improvement Tool (DIT): A tool to assess desire for improvement in psoriasis patients.

No validated instrument exists to measure desire for improvement in psoriasis patients. To address this void, we conducted a single-center longitudinal study of 268 moderate-to-severe psoriasis patients to psychometrically validate the Desired Improvement Tool (DIT). The DIT is a single-item instrument scored 0-5 by the patient. A 0 indicates the patient is satisfied with disease level and does not desire further treatment. A 5 indicates a large amount of improvement is desired. The DIT demonstrated high test-retest reliability (Spearman, r = 0.97). Predictive and construct validity were moderate-to-high: r = 0.70 for BSA, 0.67 for PASI, and 0.56 for PGA and r = 0.67 for Life Quality Assessment (LQA), respectively. A sensitivity analysis revealed the DIT responded to changes in BSA. As a psychometrically valid tool, the DIT may guide clinical management of psoriasis patients by capturing an important clinical construct in an expedient and quantifiable manner.

Radiographic Progression of Patients With Psoriatic Arthritis Who Achieve Minimal Disease Activity in Response to Golimumab Therapy: Results Through 5 Years of a Randomized, Placebo-Controlled Study.

OBJECTIVE: To evaluate long-term outcomes in psoriatic arthritis (PsA) patients who achieved or did not achieve minimal disease activity (MDA) through 5 years of golimumab treatment in the GO-REVEAL trial. METHODS: The GO-REVEAL trial was a phase III, randomized, double-blind trial with placebo-control through week 24 followed by an open-label extension of golimumab 50/100 mg treatment up to 5 years. In these post-hoc analyses, MDA was defined by the presence of ≥5 of 7 PsA outcome measures (≤1 swollen joint, ≤1 tender joint, Psoriasis Area and Severity Index [PASI] ≤1, patient pain score ≤15, patient global disease activity score ≤20 [range 0-100], Health Assessment Questionnaire disability index [HAQ DI] ≤0.5, and ≤1 tender enthesis point). RESULTS: Treatment with golimumab yielded significantly higher MDA response rates versus patients randomized to placebo at week 14 (23.5% versus 1.0%; P < 0.0001), week 24 (28.1% versus 7.7%; P < 0.0001), and week 52 (42.4% versus 30.2%; P = 0.037). MDA was achieved at least once by ∼50% of golimumab-treated patients overall. Irrespective of treatment randomization, achievement of MDA at ≥3 and ≥4 consecutive visits was associated with significantly less radiographic progression and more improvement in MDA components allowing specific assessment of physical function (HAQ DI) and overall disease activity (patient global assessment of disease activity) at week 256 versus patients not achieving MDA. Logistic regression analyses indicated that a 1-unit higher baseline HAQ DI score yielded a significantly lower likelihood of achieving MDA at ≥3 (odds ratio 0.514 [95% confidence interval 0.321-0.824]; P = 0.006) and ≥4 (odds ratio 0.480 [95% confidence interval 0.290-0.795]; P = 0.004) consecutive visits. CONCLUSION: Among golimumab-treated PsA patients, better long-term functional improvement, patient global assessment, and radiographic outcomes were observed when patients achieved persistent MDA.

Genome-wide Association Analysis of Psoriatic Arthritis and Cutaneous Psoriasis Reveals Differences in Their Genetic Architecture.

Psoriasis vulgaris (PsV) is a common inflammatory and hyperproliferative skin disease. Up to 30% of people with PsV eventually develop psoriatic arthritis (PsA), an inflammatory musculoskeletal condition. To discern differences in genetic risk factors for PsA and cutaneous-only psoriasis (PsC), we carried out a genome-wide association study (GWAS) of 1,430 PsA case subjects and 1,417 unaffected control subjects. Meta-analysis of this study with three other GWASs and two targeted genotyping studies, encompassing a total of 9,293 PsV case subjects, 3,061 PsA case subjects, 3,110 PsC case subjects, and 13,670 unaffected control subjects of European descent, detected 10 regions associated with PsA and 11 with PsC at genome-wide (GW) significance. Several of these association signals (IFNLR1, IFIH1, NFKBIA for PsA; TNFRSF9, LCE3C/B, TRAF3IP2, IL23A, NFKBIA for PsC) have not previously achieved GW significance. After replication, we also identified a PsV-associated SNP near CDKAL1 (rs4712528, odds ratio [OR] = 1.16, p = 8.4 × 10(-11)). Among identified psoriasis risk variants, three were more strongly associated with PsC than PsA (rs12189871 near HLA-C, p = 5.0 × 10(-19); rs4908742 near TNFRSF9, p = 0.00020; rs10888503 near LCE3A, p = 0.0014), and two were more strongly associated with PsA than PsC (rs12044149 near IL23R, p = 0.00018; rs9321623 near TNFAIP3, p = 0.00022). The PsA-specific variants were independent of previously identified psoriasis variants near IL23R and TNFAIP3. We also found multiple independent susceptibility variants in the IL12B, NOS2, and IFIH1 regions. These results provide insights into the pathogenetic similarities and differences between PsC and PsA.

Essential Truths for the Care and Management of Moderate-to-Severe Psoriasis.

Psoriasis is a systemic inflammatory disease. Effective management requires treatment with agents targeting inflammation in skin, joints, and other tissues. Biologics for psoriasis are directed at more specific targets, have a better safety profile, are better tolerated, and are more effective than conventional systemic agents. Despite these advances, many patients with psoriasis remain undertreated, and overall patient satisfaction remains low. The dichotomy between ideal therapeutic outcomes and suboptimal outcomes (which are currently commonplace) is likely largely due to misperceptions about psoriasis and biologic treatments. This article discusses these misperceptions, including the notions that psoriasis is a benign disorder, and that conventional systemic therapies are safer than biologics and adequate for most patients with moderate-to-severe disease. We present practical and evidence-based discussions to refute these misconceptions and provide useful resources for providers and patients that support access to advanced therapies. We believe that biologics represent optimal treatment for most patients with moderate-to-severe psoriasis, and until more effective approaches are generated, these efficacious and target-specific approaches should become the standard of care.

Quality of life assessment in cosmetics: specificity and interest of the international BeautyQol instrument.

The wide use of cosmetics and their perceived benefits upon well-being imply objective descriptions of their effects upon the different dimensions contributing to the quality of life (QoL). Such a goal pleas for using relevant and validated scientific instruments with robust measurement methods. This paper discusses the interest of the new validated questionnaire BeautyQoL specifically designed to assess the effect of cosmetic products on physical appearance and QoL. After conducting a review of skin appearance and QoL, three phases of the international codevelopment have been carried out in the following sequence: semi-directed interviews (Phase 1), acceptability study (Phase 2), and validation study (Phase 3). Data collection and validation process have been carried out in 16 languages. This review confirms that QoL instruments developed in dermatology are not suitable to assess cosmetic products, mainly because of their lack of sensitivity. General acceptability of BeautyQol was very good. Forty-two questions have been structured in five dimensions that explained 76.7% of the total variance: Social Life, Self-confidence, Mood, Vitality, and Attractiveness. Cronbach's alpha coefficients are between 0.932 and 0.978, confirming the good internal consistency of the results. The BeautyQol questionnaire is the first international instrument specific to cosmetic products and physical appearance that has been validated in 16 languages and could be used in a number of clinical trials and descriptive studies to demonstrate the added value of these products on the QoL.

Impact of pigmentary disorders on quality of life in Japan: Interest of the BeautyQoL instrument.

Skin pigmentary disorders and uneven skin tone represent common cosmetic concerns in Japan where fairer skin is culturally desirable. As the demographics of Asian countries continue to evolve, there is a need to understand the impact of cosmetic skin concerns on quality of life (QoL). 199 Japanese women self-claiming facial skin pigmentation disorders were asked to complete the BeautyQoL questionnaire, and the results were compared with those of a control group of 200 women. Of the five dimensions of the BeautyQoL questionnaire, the dimension "mood" appeared to be significantly lower in the group presenting facial dark spots, as compared with the control group (p < 0.05). In the group presenting facial dark spots, the five dimensions and the global score showed that subjects concerned had lower scores than subjects less concerned, even if statistical significance was not reached. This study confirms that common pigmentary disorders such as facial black spots may negatively impact QoL. Further comparative studies with a controlled randomized design would be necessary to confirm these findings.

Enhanced meta-analysis and replication studies identify five new psoriasis susceptibility loci.

Psoriasis is a chronic autoimmune disease with complex genetic architecture. Previous genome-wide association studies (GWAS) and a recent meta-analysis using Immunochip data have uncovered 36 susceptibility loci. Here, we extend our previous meta-analysis of European ancestry by refined genotype calling and imputation and by the addition of 5,033 cases and 5,707 controls. The combined analysis, consisting of over 15,000 cases and 27,000 controls, identifies five new psoriasis susceptibility loci at genome-wide significance (P<5 × 10(-8)). The newly identified signals include two that reside in intergenic regions (1q31.1 and 5p13.1) and three residing near PLCL2 (3p24.3), NFKBIZ (3q12.3) and CAMK2G (10q22.2). We further demonstrate that NFKBIZ is a TRAF3IP2-dependent target of IL-17 signalling in human skin keratinocytes, thereby functionally linking two strong candidate genes. These results further integrate the genetics and immunology of psoriasis, suggesting new avenues for functional analysis and improved therapies.

Genome-wide meta-analysis identifies multiple novel associations and ethnic heterogeneity of psoriasis susceptibility.

Psoriasis is a common inflammatory skin disease with complex genetics and different degrees of prevalence across ethnic populations. Here we present the largest trans-ethnic genome-wide meta-analysis (GWMA) of psoriasis in 15,369 cases and 19,517 controls of Caucasian and Chinese ancestries. We identify four novel associations at LOC144817, COG6, RUNX1 and TP63, as well as three novel secondary associations within IFIH1 and IL12B. Fine-mapping analysis of MHC region demonstrates an important role for all three HLA class I genes and a complex and heterogeneous pattern of HLA associations between Caucasian and Chinese populations. Further, trans-ethnic comparison suggests population-specific effect or allelic heterogeneity for 11 loci. These population-specific effects contribute significantly to the ethnic diversity of psoriasis prevalence. This study not only provides novel biological insights into the involvement of immune and keratinocyte development mechanism, but also demonstrates a complex and heterogeneous genetic architecture of psoriasis susceptibility across ethnic populations.