The Genetic Basis of Psoriasis

Digital twins in dermatology, current status, and the road ahead

Digital twins, innovative virtual models synthesizing real-time biological, environmental, and lifestyle data, herald a new era in personalized medicine, particularly dermatology. These models, integrating medical-purpose Internet of Things (IoT) devices, deep and digital phenotyping, and advanced artificial intelligence (AI), offer unprecedented precision in simulating real-world physical conditions and health outcomes. Originating in aerospace and manufacturing for system behavior prediction, their application in healthcare signifies a paradigm shift towards patient-specific care pathways. In dermatology, digital twins promise enhanced diagnostic accuracy, optimized treatment plans, and improved patient monitoring by accommodating the unique complexities of skin conditions. However, a comprehensive review across PubMed, Embase, Web of Science, Cochrane, and Scopus until February 5th, 2024, underscores a significant research gap; no direct studies on digital twins' application in dermatology is identified. This gap signals challenges, including the intricate nature of skin diseases, ethical and privacy concerns, and the necessity for specialized algorithms. Overcoming these barriers through interdisciplinary efforts and focused research is essential for realizing digital twins' potential in dermatology. This study advocates for a proactive exploration of digital twins, emphasizing the need for a tailored approach to dermatological care that is as personalized as the patients themselves.

Utility of IL-36 immunostaining in distinguishing psoriasis from pityriasis rosea and pityriasis lichenoides

BACKGROUND

Psoriasis is an inflammatory skin disease driven by upregulation of cytokines in the Th17 pathway, including interleukin-36 (IL-36). Previous studies have highlighted the utility of IL-36 immunostaining for psoriasis compared to spongiotic dermatitis and other psoriasiform dermatoses; however, no study has examined the role of IL-36 staining in distinguishing psoriasis from pityriasis rosea (PR) and pityriasis lichenoides (PL), known histologic mimickers of psoriasis.

METHODS

We compared the immunostaining pattern of IL-36 for 21 PR cases, 22 PL cases, and 10 psoriasis cases. We graded the immunostaining as 0, negative; 1, focal weak; 2, diffuse weak; 3, focal, strong; or 4, diffuse strong. We further categorized stains as negative (0-2 score) or positive (3-4 score) and utilized Fisher's exact test to compare the immunostaining pattern of these entities.

RESULTS

All psoriasis specimens were positive for IL-36, whereas all PR specimens were negative (p = 0.00000002). Twenty PL specimens were negative (p = 0.000001). Nine of 10 pityriasis lichenoides et varioliformis acuta cases were negative (p = 0.00012), and 11 of 12 cases of pityriasis lichenoides chronica were negative (p = 0.00003).

CONCLUSIONS

Our findings highlight the potential role of IL-36 immunostaining in distinguishing psoriasis from other psoriasiform dermatoses, including PR and PL.

Helicobacter pylori infection in psoriatic patients and its relation to psoriasis severity: Cross Sectional Study

BACKGROUND

Psoriasis is a prevalent inflammatory skin condition that can be recognized by silvery-white scales on plaques and erythematous papules, despite the fact that psoriasis appears to have multiple causes. Helicobacter pylori (H. pylori) has been investigated recently as a potential infectious etiological component.

AIMS

The objective of the study was to evaluate the prevalence of H. pylori infection in psoriatic patients compared to that of healthy controls and determine whether the degree of psoriasis and H. pylori infection were related.

PATIENTS AND METHODS

The dermatology, venerology, and andrology department at South Valley University Outpatient Clinic carried out this cross-sectional study. Psoriatic patients of both sexes and ages were included. In addition to the control group, H. Pylori antigen was measured from psoriatic and control groups by using H. pylori stool antigen-enzyme linked immunosorbent assay (HpSA-ELISA), a test for H. pylori stool antigen. More than 20 ng/mL of antigen proved positive, or less than 15 ng/mL proved negative.

RESULTS

There was a significant difference between psoriatic patients and control regarding H. pylori infection (p = 0.046): (30.66%) positive in controls, (45.33%) positive in psoriatic patients. Both groups were matched for age (p = 0.908), that is, the mean age of psoriatic patients was 37.44 ± 15.79 years, and the control group was 37.15 ± 15.15 years. Twenty-five psoriatic patients in each group: mild, moderate, and severe psoriasis according to the Psoriasis Area Severity Index (PASI) score. No significant correlation between H. pylori infection and PASI, age, or duration of illness in psoriatic patients.

CONCLUSIONS

Patients with psoriasis had greater rates of H. pylori infection but didn't affect the severity of psoriasis.

Association between United States Environmental Contaminants and the Prevalence of Psoriasis Derived from the National Health and Nutrition Examination Survey

(1) Background: Prolonged coexposure to environmental contaminants is reportedly associated with adverse impacts on skin health. However, the collective effects of contaminant mixtures on psoriasis prevalence remain unclear. (2) Methods: A nationally representative cohort study was conducted using data from the National Health and Nutrition Examination Survey 2003-2006 and 2009-2014. The association between contaminant exposures and psoriasis prevalence was analyzed through weighted quantile sum regressions, restricted cubic splines, and multivariable logistic regression. (3) Results: 16,453 participants and 60 contaminants in 8 groups were involved. After adjusting for demographics and comorbidities, exposure to urinary perchlorate, nitrate, and thiocyanate mixtures (OR: 1.10, 95% CI: 1.00-1.21) demonstrated a significant positive linear association with psoriasis prevalence. Ethyl paraben (OR: 1.21, 95% CI: 1.02-1.44) exhibited a significant positive correlation with psoriasis risk as an individual contaminant. The association between blood cadmium, lead, and mercury mixtures (OR: 1.10, 95% CI: 1.00-1.21), urinary perchlorate, nitrate, and thiocyanate mixtures (OR: 1.16, 95% CI: 1.00-1.34), and psoriasis prevalence was more pronounced in the lower healthy lifestyle score subgroup. (4) Conclusions: Exposure to perchlorate, nitrate, and thiocyanate mixtures, and ethyl paraben was associated with an elevated psoriasis prevalence. Furthermore, the association between cadmium and lead and mercury mixtures as well as perchlorate, nitrate and thiocyanate mixtures, and psoriasis prevalence was more pronounced in individuals with less healthy lifestyles.

Exploring the impact of m6A modification on immune diseases: mechanisms and therapeutic implication

N6-methyladenosine (m6A) is a chemical modification of RNA and has become a widely discussed topic among scientific researchers in recent years. It is distributed in various organisms, including eukaryotes and bacteria. It has been found that m6A is composed of writers, erasers and readers and is involved in biological functions such as splicing, transport and translation of RNA. The balance of the human immune microenvironment is important for human health abnormalities. Increasing studies have found that m6A affects the development of immune diseases such as inflammatory enteritis and systemic lupus erythematosus (SLE) by participating in the homeostatic regulation of the immune microenvironment in vivo. In this manuscript, we introduce the composition, biological function, regulation of m6A in the immune microenvironment and its progression in various immune diseases, providing new targets and directions for the treatment of immune diseases in clinical practice.

The Intersection of the Pathogenic Processes Underlying Psoriasis and the Comorbid Condition of Obesity

In the past decade, our understanding of psoriasis pathogenesis has made significant steps forward, leading to the development of multiple game-changing therapies. While psoriasis primarily affects the skin, it is increasingly recognized as a systemic disease that can have effects beyond the skin. Obesity is associated with more severe forms of psoriasis and can potentially worsen the systemic inflammation and metabolic dysfunction seen in psoriatic patients. The exact mechanisms underlying the link between these two conditions are not fully understood, but it is believed that chronic inflammation and immune dysregulation play a role. In this review, we examine the existing body of knowledge regarding the intersection of pathogenic processes responsible for psoriasis and obesity. The ability of biological therapies to reduce systemic and obesity-related inflammation in patients with psoriasis will be also discussed.

Review: A Contemporary, Multifaced Insight into Psoriasis Pathogenesis

Psoriasis is a chronic recurrent inflammatory autoimmune pathology with a significant genetic component and several interferences of immunological cells and their cytokines. The complex orchestration of psoriasis pathogenesis is related to the synergic effect of immune cells, polygenic alterations, autoantigens, and several other external factors. The major act of the IL-23/IL-17 axis, strongly influencing the inflammatory pattern established during the disease activity, is visible as a continuous perpetuation of the pro-inflammatory response and keratinocyte activation and proliferation, leading to the development of psoriatic lesions. Genome-wide association studies (GWASs) offer a better view of psoriasis pathogenic pathways, with approximately one-third of psoriasis's genetic impact on psoriasis development associated with the MHC region, with genetic loci located on chromosome 6. The most eloquent genetic factor of psoriasis, PSORS1, was identified in the MHC I site. Among the several factors involved in its complex etiology, dysbiosis, due to genetic or external stimulus, induces a burst of pro-inflammatory consequences; both the cutaneous and gut microbiome get involved in the psoriasis pathogenic process. Cutting-edge research studies and comprehensive insights into psoriasis pathogenesis, fostering novel genetic, epigenetic, and immunological factors, have generated a spectacular improvement over the past decades, securing the path toward a specific and targeted immunotherapeutic approach and delayed progression to inflammatory arthritis. This review aimed to offer insight into various domains that underline the pathogenesis of psoriasis and how they influence disease development and evolution. The pathogenesis mechanism of psoriasis is multifaceted and involves an interplay of cellular and humoral immunity, which affects susceptible microbiota and the genetic background. An in-depth understanding of the role of pathogenic factors forms the basis for developing novel and individualized therapeutic targets that can improve disease management.

RNA-Based Antipsoriatic Gene Therapy: An Updated Review Focusing on Evidence from Animal Models

Psoriasis presents as a complex genetic skin disorder, characterized by the interaction between infiltrated immune cells and keratinocytes. Substantial progress has been made in understanding the molecular mechanisms of both coding and non-coding genes, which has positively impacted clinical treatment approaches. Despite extensive research into the genetic aspects of psoriasis pathogenesis, fully grasping its epigenetic component remains a challenging endeavor. In response to the pressing demand for innovative treatments to alleviate inflammatory skin disorders, various novel strategies are under consideration. These include gene therapy employing antisense nucleotides, silencing RNA complexes, stem cell therapy, and antibody-based therapy. There is a pressing requirement for a psoriasis-like animal model that replicates human psoriasis to facilitate early preclinical evaluations of these novel treatments. The authors conduct a comprehensive review of various gene therapy in different psoriasis-like animal models utilized in psoriasis research. The animals included in the list underwent skin treatments such as imiquimod application, as well as genetic and biologic injections, and the results of these interventions are detailed. Animal models play a crucial role in translating drug discoveries from the laboratory to clinical practice, and these models aid in improving the reproducibility and clinical applicability of preclinical data. Numerous animal models with characteristics similar to those of human psoriasis have proven to be useful in understanding the development of psoriasis. In this review, the article focuses on RNA-based gene therapy exploration in different types of psoriasis-like animal models to improve the treatment of psoriasis.

Identification of immunological patterns characterizing immune-related psoriasis reactions in oncological patients in therapy with anti-PD-1 checkpoint inhibitors

Introduction

Immunotherapy with biologics targeting programmed cell death protein-1 (PD-1) is highly effective in the treatment of various malignancies. Nevertheless, it is frequently responsible for unexpected cutaneous manifestations, including psoriasis-like dermatitis. The pathogenesis of anti-PD-1-induced psoriasis has yet to be clarified, even though it is plausible that some innate and adaptive immunity processes are in common with canonical psoriasis. The genetic predisposition to psoriasis of patients could also be a contributing factor. Here, we investigated the immunological and genetic profiles of two patients with metastatic melanoma and one patient affected by lung cancer, who developed severe psoriasis after receiving anti-PD-1 nivolumab therapy.

Methods

The immune patterns of the three patients were compared with those detectable in classical, chronic plaque-type psoriasis or paradoxical psoriasis induced by anti-TNF-α therapy, mostly sustained by adaptive and innate immunity processes, respectively. Therefore, immunohistochemistry and mRNA analyses of innate and adaptive immunity molecules were conducted on skin biopsy of patients. Genetic analysis of polymorphisms predisposing to psoriasis was carried out by NGS technology.

Results

We found that anti-PD-1-induced psoriasis showed immunological features similar to chronic psoriasis, characterized by the presence of cellular players of adaptive immunity, with abundant CD3+, CD8+ T cells and CD11c+ dendritic cells infiltrating skin lesions, and producing IL-23, IL-6, TNF-α, IFN-γ and IL-17. On the contrary, a lower number of innate immunity cells (BDCA2+ plasmacytoid dendritic cells, CD15+ neutrophils, CD117+ mast cells) and reduced IFN-α/β, lymphotoxin (LT)-α/β, were observed in anti-PD-1-induced psoriasis lesions, as compared with anti-TNF-α-induced paradoxical psoriasis. Importantly, the disintegrin and metalloprotease domain containing thrombospondin type 1 motif-like 5 (ADAMTSL5) psoriasis autoantigen was significantly upregulated in psoriasis lesions of anti-PD-1-treated patients, at levels comparable with chronic plaque-type psoriasis. Finally, NGS analysis revealed that all patients carried several allelic variants in psoriasis susceptibility genes, such as HLA-C, ERAP1 and other genes of the major psoriasis susceptibility PSORS1 locus.

Discussion

Our study showed that adaptive immunity predominates over innate immunity in anti-PD-1-induced psoriasis lesions, consistently with the local ADAMTSL5 overexpression. The presence of numerous SNPs in psoriasis susceptibility genes of the three patients also suggested their strong predisposition to the disease.

Plaque Psoriasis Exacerbation and COVID-19 Vaccination: Assessing the Characteristics of the Flare and the Exposome Parameters

The diverse patient population and widespread vaccination in the COVD-19 era make vaccine-triggered episodes of psoriasis an ideal model of exposome research. This scenario explores the fine balance between protective and exacerbating factors, providing insights into the complex relationship between environmental exposure and psoriasis immunopathogenesis when a trigger appears, such as that of the hyperinflammatory state induced by the COVID-19 vaccine. Analyzing interactions between vaccine-induced phenomena and exposome parameters may provide clinically relevant information important for personalized medicine decision-making. We performed a literature review seeking patients with plaque psoriasis flares or new onset or change in plaque psoriasis into another psoriasis subtype, such as pustular or erythrodermic flare, focusing on the inner and external exposome traits of patients. We identified 71 patients with plaque psoriasis flares, 12 patients with new-onset psoriasis, and 17 with plaque psoriasis subtype change, and assessed the COVID-19 vaccine-induced plaque psoriasis in terms of clinical presentation, post-vaccination flare period and treatment status, as well as inner exposome parameters (genomics, oxidative stress, hormonal impact due to gender, aging, skin color) and external parameters (UV, infectomics). Novel data on psoriasis flares following COVID-19 vaccination are primarily obtained by combining exposome and vaccine-triggered episode features and characteristics and comparing them with similar psoriasis flares unrelated to COVID-19 vaccination.

The role of m6A RNA methylation in autoimmune diseases: Novel therapeutic opportunities

N6-methyladenosine (m6A) modifications, as one of the most common forms of internal RNA chemical modifications in eukaryotic cells, have gained increasing attention in recent years. The m6A RNA modifications exert various crucial roles in various biological processes, such as embryonic development, neurogenesis, circadian rhythms, and tumorigenesis. Recent advances have highlighted that m6A RNA modification plays an important role in immune response, especially in the initiation and progression of autoimmune diseases. In this review, we summarized the regulatory mechanisms of m6A methylation and its biological functions in the immune system and mainly focused on recent progress in research on the potential role of m6A RNA methylation in the pathogenesis of autoimmune diseases, thus providing possible biomarkers and potential targets for the prevention and treatment of autoimmune diseases.

Involvement of transcribed lncRNA uc.291 in hyperproliferative skin disorders

The uc.291 transcript controls keratinocytes differentiation by physical interaction with ACTL6A and subsequent induction of transcription of the genes belonging to the epidermal differentiation complex (EDC). Uc.291 is also implicated in the dedifferentiation phenotype seen in poorly differentiated cutaneous squamous cell carcinomas. Here, we would like to investigate the contribution of uc.291 to the unbalanced differentiation state of keratinocytes observed in hyperproliferative skin disorders, e. g., psoriasis. Psoriasis is a multifactorial inflammatory disease, caused by alteration of keratinocytes homeostasis. The imbalanced differentiation state, triggered by the infiltration of immune cells, represents one of the events responsible for this pathology. In the present work, we explore the role of uc.291 and its interactor ACTL6A in psoriasis skin, using quantitative real-time PCR (RT-qPCR), immunohistochemistry and bioinformatic analysis of publicly available datasets. Our data suggest that the expression of the uc.291 and of EDC genes loricrin and filaggrin (LOR, FLG) is reduced in lesional skin compared to nonlesional skin of psoriatic patients; conversely, the mRNA and protein level of ACTL6A are up-regulated. Furthermore, we provide evidence that the expression of uc.291, FLG and LOR is reduced, while ACTL6A mRNA is up-regulated, in an in vitro psoriasis-like model obtained by treating differentiated keratinocytes with interleukin 22 (IL-22). Furthermore, analysis of a publicly available dataset of human epidermal keratinocytes treated with IL-22 (GSE7216) confirmed our in vitro results. Taken together, our data reveal a novel role of uc.291 and its functional axis with ACTL6A in psoriasis disorder and a proof of concept that biological inhibition of this molecular axis could have a potential pharmacological effect against psoriasis and, in general, in skin diseases with a suppressed differentiation programme.

Disentangling the complexity of psoriasis in the post-genome-wide association era

In recent years, genome-wide association studies (GWAS) have been instrumental in unraveling the genetic architecture of complex diseases, including psoriasis. The application of large-scale GWA studies in psoriasis has illustrated several associated loci that participate in the cutaneous inflammation, however explaining a fraction of the disease heritability. With the advent of high-throughput sequencing technologies and functional genomics approaches, the post-GWAS era aims to unravel the functional mechanisms underlying the inter-individual variability in psoriasis patients. In this review, we present the key advances of psoriasis GWAS in under-represented populations, rare, non-coding and structural variants and epistatic phenomena that orchestrate the interplay between different cell types. We further review the gene-gene and gene-environment interactions contributing to the disease predisposition and development of comorbidities through Mendelian randomization studies and pleiotropic effects of psoriasis-associated loci. We finally examine the holistic approaches conducted in psoriasis through system genetics and state-of-the-art transcriptomic analyses, discussing their potential implication in the expanding field of precision medicine and characterization of comorbidities.

Polymorphisms in corticotrophin-releasing hormone-proopiomalanocortin (CRH-POMC) system genes: Neuroimmune contributions to psoriasis disease

BACKGROUND

Skin is a target organ and source of the corticotropin-releasing hormone-proopiomelanocortin (CRH-POMC) system, operating as a coordinator and executor of responses to stress. Environmental stress exacerbates and triggers inflammatory skin diseases through modifying the cellular components of the immune system supporting the importance of CRH-POMC system in the pathogenesis of psoriasis. The aim of this study was to analyse the association of CRH-POMC polymorphisms with psoriasis and evaluate transcript expression of lesional psoriatic and normal skin in RNA-seq data.

METHODS

Samples of 104 patients with psoriasis and 174 healthy controls were genotyped for 42 single nucleotide polymorphisms (SNPs) of CRH-POMC using Applied Biosystems SNPlex™ method. The transcript quantification was performed using Salmon software v1.3.0.

RESULTS

This study demonstrated the associations between melanocortin 1 receptor (MC1R) polymorphisms rs2228479, rs3212369, dopachrome tautomerase (DCT) polymorphisms rs7987802, rs2031526, rs9524501 and psoriasis in the Tatar population. Very strong association was evident for the SNP rs7987802 in the DCT gene (pc  = 5.95е-006) in psoriasis patients. Additionally, the haplotype analysis provided AT DCT (rs7992630 and rs7987802) and AGA MC1R (rs3212358, 2228479 and 885479) haplotypes significantly associated (pc  ˂ 0.05) with psoriasis in the Tatar population, supporting the involvement of DCT and MC1R to the psoriasis susceptibility. Moreover, MC1R-203 and DCT-201 expression levels were decreased in psoriasis lesional skin compared with healthy control skin.

CONCLUSIONS

This study is the first to identify genetic variants of the MC1R and DCT genes significantly associated with psoriasis in Tatar population. Our results support potential roles of CRH-POMC system genes and DCT in the pathogenesis of psoriasis.

Metabolic Disorders and Psoriasis: Exploring the Role of Nutritional Interventions

(1) Background: Psoriasis is a chronic autoimmune disease with a close relationship with metabolic diseases such as obesity, diabetes, and dyslipidemia. The aim of this review was to identify the relationship between psoriasis, metabolic diseases, and dietetic therapies. According to recent findings, there is a strong association between psoriasis and obesity as well as vitamin D and micronutrient deficiencies. (2) Methods: This review was conducted via PubMed, aiming to search for studies involving psoriasis linked with metabolic disorders or with nutritional treatments. (3) Results: Our review shows that a healthy lifestyle can positively influence the course of the disease. The maintaining of a proper body weight together with physical activity and good nutritional choices are associated with an improvement in psoriasis severity. A Mediterranean diet rich in fiber, vitamins, and polyphenols may indeed be a strategy for controlling psoriasis symptoms. The effectiveness of this diet lies not only in its anti-inflammatory power, but also in its ability to favorably influence the intestinal microbiota and counteract dysbiosis, which is a risk factor for many autoimmune diseases. (4) Conclusions: In synergy with standard therapy, the adoption of an appropriate diet can be recommended to improve the clinical expression of psoriasis and reduce the incidence of comorbidities.

Potential roles of inflammasomes in the pathophysiology of Psoriasis: A comprehensive review

Psoriasis is an inflammatory skin disease whose pathophysiology is attributed to both innate and adaptive immune cells and molecules. Despite the crucial roles of the immune system in psoriasis, it cannot be categorized as an autoimmune disease because of the lack of main signs of autoimmunity, such as specific antibodies, well-defined antigens, and autoimmune genetic risk factors. The presence of some cellular and molecular properties, such as the presence of neutrophils in skin lesions and the activation of the innate immune system, attributes psoriasis to a group of diseases called autoinflammatory disorders. Autoinflammatory diseases refer to a group of inherited disorders whose main manifestations are recurrent fever, a high level of acute-phase reactant, and a tendency for inflammation of the skin, joints, and other organs like the nervous system. In most autoinflammatory disorders, it has been seen that complexes of the high-molecular-weight protein named inflammasomes have significant roles. The inflammasome complex usually is formed and activated in the stimulated immune cell cytoplasm, and its activation consequently leads to inflammatory events such as producing of active caspase-1, mature interleukin-1β (IL-1β), and IL-18 and can cause an inflammatory programmed cell death called pyroptosis. Since the identification of inflammasomes, it has been shown that there are close links between them and hereditary and acquired autoinflammatory diseases like psoriasis. In this review, we aim to focus on well-defined inflammasome and their role in the pathophysiology of psoriasis.

A Pilot Genome-Wide Association Study Identifies Novel Markers of Metabolic Syndrome in Patients with Psoriasis

BACKGROUND

Recent studies have reported that psoriasis is associated with the development of metabolic syndrome. Genome-wide association studies have been used to discover gene variant markers that occur frequently in case group in relation to specific diseases.

OBJECTIVE

The aim of the present study was to investigate the variants of specific genes involved in metabolic syndrome associated with psoriasis.

METHODS

A total of 95 psoriasis patients were recruited and divided into two groups: one with metabolic syndrome (38 patients) and the other without (57 patients). After genotyping, imputation, and quality checking, the association between the several single nucleotide polymorphisms and metabolic syndrome in psoriasis was tested, followed by gene set enrichment analysis.

RESULTS

We found 76 gene polymorphisms that conferred an increased risk for metabolic syndrome in patients with psoriasis. Four single nucleotide polymorphisms (rs17154774 of FRMD4A, rs77498336 of GPR116, rs75949580 and rs187682251 of MAPK4) showed the strongest association between metabolic syndrome and psoriasis. The epidermal growth factor receptor protein was located at the center of the protein interactions for the gene polymorphisms.

CONCLUSION

This study identified several previously unknown polymorphisms associated with metabolic syndrome in psoriasis. These results highlight the potential for future genetic studies to elucidate the development, and ultimately prevent the onset, of metabolic syndrome in patients with psoriasis.

The Genetic Susceptibility to Psoriasis and the Relationship of Linked Genes to Our Treatment Options

Understanding the factors creating genetic susceptibility in psoriasis may provide a basis for improving targeted treatment strategies. In this review, we discuss the genes linked to the pathogenesis of psoriasis and their relationship to the available treatment options. To identify the relevant genetic markers and treatments, we searched PubMed, Google Scholar, MEDLINE, and Web of Science with keywords, including genetic susceptibility to psoriasis, genetics and psoriasis, psoriasis treatments, and biologics treatments in psoriasis. The articles in English from database inception to 1/1/23 were included. Case reports and series were excluded. Gene variant forms commonly implicated in the pathogenesis of psoriasis include those encoding for interleukins, interferons, and other mediators involved in inflammatory pathways, such as JAK/STAT, and NF-κB. Several of the treatments for psoriasis (for example IL23 and TYK2 inhibitors) target the products of genes linked to psoriasis. Multiple genes are linked to the pathogenesis of psoriasis. This understanding may provide an avenue for the development of new psoriasis treatment strategies and for more effective, safer treatment outcomes.

Atopic Polygenic Risk Score Is Associated with Paradoxical Eczema Developing in Patients with Psoriasis Treated with Biologics

Biologic therapies for psoriasis can cause paradoxical eczema. The role of genetic factors in its pathogenesis is unknown. To identify risk variants, we conducted a GWAS of 3,212 patients with psoriasis, of whom 88 developed paradoxical eczema. Two lead SNPs reached genome-wide significance (P ≤ 5 × 10-8) for association with paradoxical eczema: rs192705221 (near UNC5B, P = 9.52 × 10-10) and rs72925168 (within SLC1A2, P = 1.66 × 10-9). Genome-wide significant SNPs from published GWAS were used to generate polygenic risk scores (PRSs) for atopic eczema, general atopic disease, or a combination, which were tested for association with paradoxical eczema. Improvement over a clinical risk model was assessed by the area under the curve. All three atopy polygenic risk scores were associated with paradoxical eczema (P < 0.05); polygenic risk score for a combination of atopic eczema and general atopic disease had the strongest association (OR = 1.83, 95% CI = 1.17-2.84, P = 0.0078). Including atopic polygenic risk scores in the multivariable model, which included age, sex, atopic background, and psoriatic arthritis history, increased the area under the curve from 0.671 to 0.681-0.686. Atopic genetic burden is associated with paradoxical eczema occurring in biologic-treated patients with psoriasis, indicating shared underlying mechanisms. Incorporating genetic risk may improve treatment outcome prediction models for psoriasis.

Systemic pharmacological treatments for chronic plaque psoriasis: a network meta-analysis

BACKGROUND

Psoriasis is an immune-mediated disease with either skin or joints manifestations, or both, and it has a major impact on quality of life. Although there is currently no cure for psoriasis, various treatment strategies allow sustained control of disease signs and symptoms. The relative benefit of these treatments remains unclear due to the limited number of trials comparing them directly head-to-head, which is why we chose to conduct a network meta-analysis.

OBJECTIVES

To compare the benefits and harms of non-biological systemic agents, small molecules, and biologics for people with moderate-to-severe psoriasis using a network meta-analysis, and to provide a ranking of these treatments according to their benefits and harms.

SEARCH METHODS

For this update of the living systematic review, we updated our searches of the following databases monthly to October 2022: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of systemic treatments in adults over 18 years with moderate-to-severe plaque psoriasis, at any stage of treatment, compared to placebo or another active agent. The primary outcomes were: proportion of participants who achieved clear or almost clear skin, that is, at least Psoriasis Area and Severity Index (PASI) 90; proportion of participants with serious adverse events (SAEs) at induction phase (8 to 24 weeks after randomisation).

DATA COLLECTION AND ANALYSIS

We conducted duplicate study selection, data extraction, risk of bias assessment, and analyses. We synthesised data using pairwise and network meta-analysis (NMA) to compare treatments and rank them according to effectiveness (PASI 90 score) and acceptability (inverse of SAEs). We assessed the certainty of NMA evidence for the two primary outcomes and all comparisons using CINeMA, as very low, low, moderate, or high. We contacted study authors when data were unclear or missing. We used the surface under the cumulative ranking curve (SUCRA) to infer treatment hierarchy, from 0% (worst for effectiveness or safety) to 100% (best for effectiveness or safety).

MAIN RESULTS

This update includes an additional 12 studies, taking the total number of included studies to 179, and randomised participants to 62,339, 67.1% men, mainly recruited from hospitals. Average age was 44.6 years, mean PASI score at baseline was 20.4 (range: 9.5 to 39). Most studies were placebo-controlled (56%). We assessed a total of 20 treatments. Most (152) trials were multicentric (two to 231 centres). One-third of the studies (65/179) had high risk of bias, 24 unclear risk, and most (90) low risk. Most studies (138/179) declared funding by a pharmaceutical company, and 24 studies did not report a funding source. Network meta-analysis at class level showed that all interventions (non-biological systemic agents, small molecules, and biological treatments) showed a higher proportion of patients reaching PASI 90 than placebo. Anti-IL17 treatment showed a higher proportion of patients reaching PASI 90 compared to all the interventions. Biologic treatments anti-IL17, anti-IL12/23, anti-IL23, and anti-TNF alpha showed a higher proportion of patients reaching PASI 90 than the non-biological systemic agents. For reaching PASI 90, the most effective drugs when compared to placebo were (SUCRA rank order, all high-certainty evidence): infliximab (risk ratio (RR) 49.16, 95% CI 20.49 to 117.95), bimekizumab (RR 27.86, 95% CI 23.56 to 32.94), ixekizumab (RR 27.35, 95% CI 23.15 to 32.29), risankizumab (RR 26.16, 95% CI 22.03 to 31.07). Clinical effectiveness of these drugs was similar when compared against each other. Bimekizumab and ixekizumab were significantly more likely to reach PASI 90 than secukinumab. Bimekizumab, ixekizumab, and risankizumab were significantly more likely to reach PASI 90 than brodalumab and guselkumab. Infliximab, anti-IL17 drugs (bimekizumab, ixekizumab, secukinumab, and brodalumab), and anti-IL23 drugs except tildrakizumab were significantly more likely to reach PASI 90 than ustekinumab, three anti-TNF alpha agents, and deucravacitinib. Ustekinumab was superior to certolizumab. Adalimumab, tildrakizumab, and ustekinumab were superior to etanercept. No significant difference was shown between apremilast and two non-biological drugs: ciclosporin and methotrexate. We found no significant difference between any of the interventions and the placebo for the risk of SAEs. The risk of SAEs was significantly lower for participants on methotrexate compared with most of the interventions. Nevertheless, the SAE analyses were based on a very low number of events with very low- to moderate-certainty evidence for all the comparisons. The findings therefore have to be viewed with caution. For other efficacy outcomes (PASI 75 and Physician Global Assessment (PGA) 0/1), the results were similar to the results for PASI 90. Information on quality of life was often poorly reported and was absent for several of the interventions.

AUTHORS' CONCLUSIONS

Our review shows that, compared to placebo, the biologics infliximab, bimekizumab, ixekizumab, and risankizumab were the most effective treatments for achieving PASI 90 in people with moderate-to-severe psoriasis on the basis of high-certainty evidence. This NMA evidence is limited to induction therapy (outcomes measured from 8 to 24 weeks after randomisation), and is not sufficient for evaluating longer-term outcomes in this chronic disease. Moreover, we found low numbers of studies for some of the interventions, and the young age (mean 44.6 years) and high level of disease severity (PASI 20.4 at baseline) may not be typical of patients seen in daily clinical practice. We found no significant difference in the assessed interventions and placebo in terms of SAEs, and the safety evidence for most interventions was very low to moderate quality. More randomised trials directly comparing active agents are needed, and these should include systematic subgroup analyses (sex, age, ethnicity, comorbidities, psoriatic arthritis). To provide long-term information on the safety of treatments included in this review, an evaluation of non-randomised studies is needed. Editorial note: This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Extracts from Seseli mairei Wolff attenuate imiquimod-induced psoriasis-like inflammation by inhibiting Th17 cells

Objective

Seseli mairei Wolff extracts (SMWE) are widely used to treat psoriasis as a Chinese medicine, but their effect and mechanism are unclear. This study verified the effect of SMWE on psoriasis by regulating Th17 cells.

Methods

HaCaT cells were treated with IL-17A in vitro to evaluate the effect of SMWE on psoriasis. In vivo, the mice psoriasis model was established using imiquimod (IMQ, 62.5 mg/d), and intragastrically treated with the different drugs for six days. The severity of skin inflammation was evaluated with Psoriasis Area and Severity Index (PASI) scores and pathology. The levels of inflammation cytokines were assessed with immunofluorescence, immunochemistry, ELISA, and real-time PCR. The number of Th17 cells was determined with flows.

Results

SMWE inhibited the proliferation of HaCaT cells and reduced the IL-17A-induced IL-6 production in vitro. In vivo, SMWE deduced the levels of IL-1β, IL-6, IL-8, IL-17A, IL-17F, IL-22, IL-23, and TNF-α, while increasing the level of IL-10 compared to the model group. SMWE also inhibited the levels of NF-κB, JAK2, and STAT3 proteins, while declining the expressions of Gr-1, and MPO. Interestingly, SMWE significantly decreased the number of Th17 cells.

Conclusion

SMWE inhibited the proliferation of HaCaT cells and attenuated the development of psoriasis lesions by inhibiting Th17 cells to regulate the levels of inflammation cytokines.

Polymorphisms of the GCLC Gene Are Novel Genetic Markers for Susceptibility to Psoriasis Associated with Alcohol Abuse and Cigarette Smoking

The aim of this pilot study was to investigate whether single nucleotide polymorphisms (SNP) in the gene encoding the catalytic subunit of glutamate cysteine ligase (GCLC) are associated with the risk and clinical features of psoriasis. A total of 944 unrelated individuals, including 474 patients with a diagnosis of psoriasis and 470 healthy controls, were recruited for the study. Six common SNPs in the GCLC gene were genotyped using the MassArray-4 system. Polymorphisms rs648595 (OR = 0.56, 95% CI 0.35-0.90; P_perm = 0.017) and rs2397147 (OR = 0.54, 95% CI 0.30-0.98; P_perm = 0.05) were associated with susceptibility to psoriasis in males. In the male group, diplotype rs2397147-C/C × rs17883901-G/G was associated with a decreased risk of psoriasis (FDR-adjusted p = 0.014), whereas diplotype rs6933870-G/G × rs17883901-G/G (FDR-adjusted p = 0.045) showed an association with an increased disease risk in females. The joint effects of SNPs with tobacco smoking (rs648595 and rs17883901) and alcohol abuse (rs648595 and rs542914) on psoriasis risk were observed (P_perm ≤ 0.05). We also found multiple sex-independent associations between GCLC gene polymorphisms and various clinical features such as earlier disease onset, the psoriatic triad, and specific localizations of skin lesions. The present study is the first to show that polymorphisms of the GCLC gene are significantly associated with the risk of psoriasis and related to its clinical features.

A partitioned 88-loci psoriasis genetic risk score reveals HLA and non-HLA contributions to clinical phenotypes in a Newfoundland psoriasis cohort

Psoriasis is an immune-mediated inflammatory skin disease typically characterized by erythematous and scaly plaques. It affects 3% of the Newfoundland population while only affecting 1.7% of the general Canadian population. Recent genome-wide association studies (GWAS) in psoriasis have identified more than 63 genetic susceptibility loci that individually have modest effects. Prior studies have shown that a genetic risk score (GRS) combining multiple loci can improve psoriasis disease prediction. However, these prior GRS studies have not fully explored the association of GRS with patient clinical characteristics. In this study, we calculated three types of GRS: one using all known GWAS SNPs (GRS-ALL), one using a subset of SNPs from the HLA region (GRS-HLA), and the last using non-HLA SNPs (GRS-noHLA). We examined the relationship between these GRS and a number of psoriasis features within a well characterized Newfoundland psoriasis cohort. We found that both GRS-ALL and GRS-HLA were significantly associated with early age of psoriasis onset, psoriasis severity, first presentation of psoriasis at the elbow or knee, and the total number of body locations affected, while only GRS-ALL was associated with a positive family history of psoriasis. GRS-noHLA was uniquely associated with genital psoriasis. These findings clarify the relationship of the HLA and non-HLA components of GRS with important clinical features of psoriasis.

Pharmacogenomics on the Treatment Response in Patients with Psoriasis: An Updated Review

The efficacy and the safety of psoriasis medications have been proved in trials, but unideal responses and side effects are noted in clinical practice. Genetic predisposition is known to contribute to the pathogenesis of psoriasis. Hence, pharmacogenomics gives the hint of predictive treatment response individually. This review highlights the current pharmacogenetic and pharmacogenomic studies of medical therapy in psoriasis. HLA-Cw*06 status remains the most promising predictive treatment response in certain drugs. Numerous genetic variants (such as ABC transporter, DNMT3b, MTHFR, ANKLE1, IL-12B, IL-23R, MALT1, CDKAL1, IL17RA, IL1B, LY96, TLR2, etc.) are also found to be associated with treatment response for methotrexate, cyclosporin, acitretin, anti-TNF, anti-IL-12/23, anti-IL-17, anti-PDE4 agents, and topical therapy. Due to the high throughput sequencing technologies and the dramatic increase in sequencing cost, pharmacogenomic tests prior to treatment by whole exome sequencing or whole genome sequencing may be applied in clinical in the future. Further investigations are necessary to manifest potential genetic markers for psoriasis treatments.

Histone deacetylase inhibitors as a potential new treatment for psoriatic disease and other inflammatory conditions

Collectively known as psoriatic disease, psoriasis and psoriatic arthritis (PsA) are immune-mediated inflammatory diseases in which patients present with cutaneous and musculoskeletal inflammation. Affecting roughly 2-3% of the world's total population, there remains unmet therapeutic needs in both psoriasis and PsA despite the availability of current immunomodulatory treatments. As a result, patients with psoriatic disease often experience reduced quality of life. Recently, a class of small molecules, commonly investigated as anti-cancer agents, called histone deacetylase (HDAC) inhibitors, have been proposed as a new promising anti-inflammatory treatment for immune- and inflammatory-related diseases. In inflammatory diseases, current evidence is derived from studies on diseases like rheumatoid arthritis (RA) and systematic lupus erythematosus (SLE), and while there are some reports studying psoriasis, data on PsA patients are not yet available. In this review, we provide a brief overview of psoriatic disease, psoriasis, and PsA, as well as HDACs, and discuss the rationale behind the potential use of HDAC inhibitors in the management of persistent inflammation to suggest its possible use in psoriatic disease.

Compositional Alteration of Gut Microbiota in Psoriasis Treated with IL-23 and IL-17 Inhibitors

Alterations in the gut microbiota composition and their associated metabolic dysfunction exist in psoriasis. However, the impact of biologics on shaping gut microbiota is not well known. This study aimed to determine the association of gut microorganisms and microbiome-encoded metabolic pathways with the treatment in patients with psoriasis. A total of 48 patients with psoriasis, including 30 cases who received an IL-23 inhibitor (guselkumab) and 18 cases who received an IL-17 inhibitor (secukinumab or ixekizumab) were recruited. Longitudinal profiles of the gut microbiome were conducted by using 16S rRNA gene sequencing. The gut microbial compositions dynamically changed in psoriatic patients during a 24-week treatment. The relative abundance of individual taxa altered differently between patients receiving the IL-23 inhibitor and those receiving the IL-17 inhibitor. Functional prediction of the gut microbiome revealed microbial genes related to metabolism involving the biosynthesis of antibiotics and amino acids were differentially enriched between responders and non-responders receiving IL-17 inhibitors, as the abundance of the taurine and hypotaurine pathway was found to be augmented in responders treated with the IL-23 inhibitor. Our analyses showed a longitudinal shift in the gut microbiota in psoriatic patients after treatment. These taxonomic signatures and functional alterations of the gut microbiome could serve as potential biomarkers for the response to biologics treatment in psoriasis.

Considerations of the Genetic Background of Obesity among Patients with Psoriasis

Psoriasis comorbidities may emerge from pleiotropic mechanisms, including common proinflammatory pathways, cellular mediators or genetic predisposition. Obesity is considered to be an independent risk factor of psoriasis, which may influence the severity of the disease and its early onset, decrease patients’ quality of life, alter response to psoriasis therapies and affect morbidity by reduced life expectancy due to cardiovascular events. Although novel approaches, including genetic techniques, have provided a wide range of new research, there are still scarce studies elaborating on the common genetic background of psoriasis and obesity. The aim of this study was to present and evaluate a possible common genetic background of psoriasis and concomitant increased body mass based on the review of the available literature.

Abnormalities of Sphingolipids Metabolic Pathways in the Pathogenesis of Psoriasis

Psoriasis is immune-mediated skin disorder affecting thousands of people. Sphingolipids (SLs) are bioactive molecules present in the epidermis, involved in the following cellular processes: proliferation, differentiation, and apoptosis of keratinocytes. Alterations in SLs synthesis have been observed in psoriatic skin. To investigate if the imbalance in lipid skin metabolism could be related to psoriasis, we analyzed the gene expression in non-lesioned and lesioned skin of patients with psoriasis available in two datasets (GSE161683 and GSE136757) obtained from National Center for Biotechnology Information (NCBI). The differentially expressed genes (DEGs) were searched for using NCBI analysis, and Gene Ontology (GO) biological process analyses were performed using the Database of Annotation, Visualization, and Integrated Discovery (DAVID) platform. Venn diagrams were done with InteractiVenn tool and heatmaps were constructed using Morpheus software. We observed that the gene expression of cytoplasmic phospholipase A₂ (PLA2G4D), glycerophosphodiester phosphodiesterase domain containing 3 (GDP3), arachidonate 12-lipoxygenase R type (ALOX12B), phospholipase B-like 1 (PLBD1), sphingomyelin phosphodiesterase 3 (SMPD3), ganglioside GM2 activator (GM2A), and serine palmitoyltransferase long chain subunit 2 (SPTLC2) was up-regulated in lesioned skin psoriasis when compared with the non-lesioned skin. These genes are related to lipid metabolism and more specifically to sphingolipids. So, in the present study, the role of sphingolipids in psoriasis pathogenesis is summarized. These genes could be used as prognostic biomarkers of psoriasis and could be targets for the treatment of patients who suffer from the disease.

The Association of HLA Alleles and Haplotypes with Age of Disease Onset in Pakistani Psoriatic Patients

INTRODUCTION

The human leukocyte antigen (HLA) region on chromosome 6p21 is well known to carry the most important genetic factors in susceptibility to psoriasis. Different HLA alleles and haplotypes have been reported to be associated with psoriasis in different populations. Psoriasis has a variable age of onset and, based on this, it can be classified into two types; type I with age of onset before 40 years of age and type II with age of onset after 40 years of age. The objective of this study was to determine the association of HLA class I and class II alleles and haplotypes with disease and stratification using age of onset in Pakistani psoriatic patients.

METHODS

A group of 603 individuals (326 cases and 277 controls) were analyzed for HLA class I and II alleles and haplotype association by sequence specific PCR. The association was further analyzed according to the age of onset of the patients.

RESULTS

We found that HLA alleles B*57 and Cw*06:02, DQB1*03:03:02 are strongly associated with early onset psoriasis, while alleles B*15, DRB1*13:02 and DQB1*03:03:02 are associated with late-onset psoriasis. Cw*06:02 allele was not associated with late-onset psoriasis patients. Allele DQB1*03:03:02 had the highest odds ratio in all patients. We found a novel association specifically with late-onset psoriasis samples with the haplotype HLA-A*11; B*15; Cw*04; DRB1*15; DQB1*05 (Pc = 3.60 × 10-7). We also found strong association with previously reported extended haplotype EH-57.1: HLA-B*57; Cw*06:02; DRB1*07:01; DQB1*03:03:02 in all our patients (Pc = 8.34 × 10-07).

CONCLUSION

Our results show that different HLA class I and II alleles and haplotypes are associated with psoriasis at different age of onset. In this study, we have reported novel alleles and haplotype association with late-onset psoriasis. Our data confirm the previous strong associations with HLA alleles and haplotypes and also reports novel alleles and haplotype association in Pakistani psoriasis patients.

Comparing Vitamin D Level Between Patients with Psoriasis and Healthy Individuals: A Systematic Review and Meta-Analysis

BACKGROUND

Psoriasis is nowadays regarded as a systemic inflammatory disorder. Among the topicals, vitamin D derivates are often applied on the skin for their anti-inflammatory and immune-modulatory properties. Vitamin D serum levels in psoriasis (PsO) patients are still debated and an eventual depletion may offer the rational to integrate anti-psoriatic therapies with oral vitamin D. Then, we aimed to perform a systematic review and meta-analysis on the current evidence towards serum vitamin D level in PsO.

METHODS

We searched in PubMed, Scopus, Web of Sciences, ScienceDirect and Science Information Database (SID) using the terms "Vitamin D" and "Psoriasis" including manuscripts in English, Italian and Persian. Duplications were excluded using EndNote software and records were screened by title, abstract and full-text. Quality assessment of studies was assessed using Newcastle Ottawa Checklist (NOS). Psoriasis odds ratio (OR) and mean serum vitamin D levels were calculated and displayed in Forest-plots. Heterogeneity indexes were evaluated using I2 and Q. Sensitivity analysis and publication biases were also considered.

RESULTS

From 3006 records extracted, after removing duplicates and analyzing full texts we finally included 19 manuscripts involving a total of 1387 PsO cases and 6939 controls. PsO patients exhibited a substantial odds ratio (3.07, 95% CI: 1.56-6.04) for lower serum vitamin D levels compared to the control group. Standardized Mean Difference (SMD) of vitamin D in PsO versus controls was -0.92 (-1.33 to -0.51).

CONCLUSION

Psoriatic patients displayed higher risk to have a vitamin D deficiency. Interventional studies to verify the preventive value are mandatory.

Management of Infections in Psoriatic Patients Treated with Systemic Therapies: A Lesson from the Immunopathogenesis of Psoriasis

Modern treatments continue to be developed based on identifying targets within the innate and adaptive immune pathways associated with psoriasis. Whilst there is a sound biologic rationale for increased risk of infection following treatment with immunomodulators, the clinical evidence is confounded by these agents being used in patients affected with several comorbidities. In an era characterized by an ever greater and growing risk of infections, it is necessary to always be updated on this risk. In this mini-review, we will discuss recent updates in psoriasis immunopathogenesis as a rationale for systemic therapy, outline the risk of infections linked to the disease itself and systemic therapy as well, and provide an overview of the prevention and management of infections.

The Challenge of Dimethyl Fumarate Repurposing in Eye Pathologies

Dimethyl fumarate (DMF) is a small molecule currently approved and used in the treatment of psoriasis and multiple sclerosis due to its immuno-modulatory, anti-inflammatory, and antioxidant properties. As an Nrf2 activator through Keap1 protein inhibition, DMF unveils a potential therapeutical use that is much broader than expected so far. In this comprehensive review we discuss the state-of-art and future perspectives regarding the potential repositioning of this molecule in the panorama of eye pathologies, including Age-related Macular Degeneration (AMD). The DMF's mechanism of action, an extensive analysis of the in vitro and in vivo evidence of its beneficial effects, together with a search of the current clinical trials, are here reported. Altogether, this evidence gives an overview of the new potential applications of this molecule in the context of ophthalmological diseases characterized by inflammation and oxidative stress, with a special focus on AMD, for which our gene-disease (KEAP1-AMD) database search, followed by a protein-protein interaction analysis, further supports the rationale of DMF use. The necessity to find a topical route of DMF administration to the eye is also discussed. In conclusion, the challenge of DMF repurposing in eye pathologies is feasible and worth scientific attention and well-focused research efforts.

Pathogenesis, multi-omics research, and clinical treatment of psoriasis

Psoriasis is a common inflammatory skin disease involving interactions between keratinocytes and immune cells that significantly affects the quality of life. It is characterized by hyperproliferation and abnormal differentiation of keratinocytes and excessive infiltration of immune cells in the dermis and epidermis. The immune mechanism underlying this disease has been elucidated in the past few years. Research shows that psoriasis is regulated by the complex interactions among immune cells, such as keratinocytes, dendritic cells, T lymphocytes, neutrophils, macrophages, natural killer cells, mast cells, and other immune cells. An increasing number of signaling pathways have been found to be involved in the pathogenesis of psoriasis, which has prompted the search for new treatment targets. In the past decades, studies on the pathogenesis of psoriasis have focused on the development of targeted and highly effective therapies. In this review, we have discussed the relationship between various types of immune cells and psoriasis and summarized the major signaling pathways involved in the pathogenesis of psoriasis, including the PI3K/AKT/mTOR, JAK-STAT, JNK, and WNT pathways. In addition, we have discussed the results of the latest omics research on psoriasis and the epigenetics of the disease, which provide insights regarding its pathogenesis and therapeutic prospects; we have also summarized its treatment strategies and observations of clinical trials. In this paper, the various aspects of psoriasis are described in detail, and the limitations of the current treatment methods are emphasized. It is necessary to improve and innovate treatment methods from the molecular level of pathogenesis, and further provide new ideas for the treatment and research of psoriasis.

The Presence of Psoriasis, Metabolic Syndrome and Their Combination Increases the Serum Levels of CRP and CD5L but Not sCD200R1 and sTLR2 in Participants

Psoriasis and metabolic syndrome (MetS) are chronic inflammatory conditions associated with the dysregulation of immune system reactivity. The inflammatory processes of both diseases have not yet been fully characterized, and the evaluation of proteins/markers that could be involved in their pathogenesis is of great importance. We selected four markers: CRP, sCD200R1, CD5L, and sTLR2; in particular, sCDR2001 has not yet been measured in the context of psoriasis and metabolic syndrome. Material and methods: In the study, 64 controls and 43 patients with psoriasis with or without a metabolic syndrome were enrolled. The levels of selected markers were measured using ELISA kits. Results: CRP levels were significantly higher in psoriasis patients, especially in the subgroup of patients with MetS compared to nonMetS patients (p < 0.01). sCD200R1 and sTLR2 were not significantly different between groups and subgroups; however, CD200R1 levels were slightly higher in both control groups compared to both groups of patients. CD5L levels were significantly higher in patients with MetS compared to nonMets patients (p < 0.02). We also evaluated the correlations between parameters in controls and patients’ groups, as well as in subgroups. Correlations between BMI and CRP were found in all groups and subgroups. Other correlations were group- and subgroup-specific. For example, in the patients’ group, CD5L correlated with sCD200R1 (p < 0.05) and in MetS controls, with age (p < 0.03). Conclusion: The results show that the presence of systemic inflammation associated with psoriasis and metabolic syndrome and their combination alters the expression of specific molecules, especially CRP and CD5L, which were significantly increased in patients with psoriasis and a metabolic syndrome compared to controls without metabolic syndromes. Correlations between CRP and BMI in all groups suggest that overweight and obesity increase the intensity of inflammation and potentiate CD5L expression. In contrast, levels of molecules that may limit inflammation were not increased in psoriasis and metabolic syndrome subjects (they were non-significantly lower compared with healthy controls), which may reflect the chronic nature of both diseases and the exhaustion of inhibitory mechanisms.

Allelic Variants of HLA-C Upstream Region, PSORS1C3, MICA, TNFA and Genes Involved in Epidermal Homeostasis and Barrier Function Influence the Clinical Response to Anti-IL-12/IL-23 Treatment of Patients with Psoriasis

Several biologic therapies have been developed to treat moderate-to-severe psoriasis, with patients exhibiting different clinical benefits, possibly due to the heterogeneity of pathogenic processes underlying their conditions. Ustekinumab targets the IL-12/IL-23-p40 subunit and inhibits type-1 and type-17 T-cell responses. Although ustekinumab is effective as both short- and long-term treatment, therapeutic response varies considerably among patients. Ustekinumab biosimilars will be commercialized in the very next future, likely broadening the use of this drug in the treatment of psoriasis patients. Our pharmacogenomic study evaluated the influence of 417 single-nucleotide polymorphisms (SNPs) in psoriasis-risk alleles on the clinical response to ustekinumab in a cohort of 152 patients affected by moderate-to-severe plaque-type psoriasis. Differences in SNP pattern characterizing HLA-Cw6+ or HLA-Cw6- patients, showing high or low responses to ustekinumab, were also analysed. We identified twelve SNPs in HLA-C upstream region (rs12189871, rs4406273, rs9348862 and rs9368670), PSORS1C3 (rs1265181), MICA (rs2523497), LCE3A-B intergenic region (rs12030223, rs6701730), CDSN (rs1042127, rs4713436), CCHCR1 (rs2073719) and in TNFA (rs1800610) genes associated with excellent response to ustekinumab. We also found that HLA-Cw6+ and HLA-Cw6- patients carried out distinct patterns of SNPs associated with different clinical responses. The assessment of HLA-C alleles, together with other genetic variants, could be helpful for defining patients who better benefit from anti-IL-12/IL-23 therapy.

Psoriasis, Is It a Microdamage of Our "Sixth Sense"? A Neurocentric View

Psoriasis is considered a multifactorial and heterogeneous systemic disease with many underlying pathologic mechanisms having been elucidated; however, the pathomechanism is far from entirely known. This opinion article will demonstrate the potential relevance of the somatosensory Piezo2 microinjury-induced quad-phasic non-contact injury model in psoriasis through a multidisciplinary approach. The primary injury is suggested to be on the Piezo2-containing somatosensory afferent terminals in the Merkel cell−neurite complex, with the concomitant impairment of glutamate vesicular release machinery in Merkel cells. Part of the theory is that the Merkel cell−neurite complex contributes to proprioception; hence, to the stretch of the skin. Piezo2 channelopathy could result in the imbalanced control of Piezo1 on keratinocytes in a clustered manner, leading to dysregulated keratinocyte proliferation and differentiation. Furthermore, the author proposes the role of mtHsp70 leakage from damaged mitochondria through somatosensory terminals in the initiation of autoimmune and autoinflammatory processes in psoriasis. The secondary phase is harsher epidermal tissue damage due to the primary impaired proprioception. The third injury phase refers to re-injury and sensitization with the derailment of healing to a state when part of the wound healing is permanently kept alive due to genetical predisposition and environmental risk factors. Finally, the quadric damage phase is associated with the aging process and associated inflammaging. In summary, this opinion piece postulates that the primary microinjury of our “sixth sense”, or the Piezo2 channelopathy of the somatosensory terminals contributing to proprioception, could be the principal gateway to pathology due to the encroachment of our preprogrammed genetic encoding.

Generalized pustular psoriasis is a disease distinct from psoriasis vulgaris: evidence and expert opinion

INTRODUCTION

Generalized pustular psoriasis (GPP) is a rare, severe, clinically heterogeneous disease characterized by flares of widespread, non-infectious, 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 perspectives 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.

Association of CARD14 Single-Nucleotide Polymorphisms with Psoriasis

Psoriasis is an immune-mediated chronic and painful disease characterized by red raised patches of inflamed skin that may have desquamation, silvery-white scales, itching and cracks. The susceptibility of developing psoriasis depends on multiple factors, with a complex interplay between genetic and environmental factors. Studies have suggested an association between autosomal dominant CARD14 (caspase recruitment domain-containing protein 14) gain-of-function mutations with the pathophysiology of psoriasis. In this study, non-synonymous single-nucleotide polymorphisms (nsSNPs) of CARD14 gene were assessed to determine their association with psoriasis in Pakistani population. A total of 123 subjects (63 patients with psoriasis and 60 normal controls) were included in this study. DNA was extracted from blood, and PCR analysis was performed followed by Sanger sequencing for 18 CARD14 specific nsSNPs (14 previously reported and the 4 most pathogenic nsSNPs identified using bioinformatics analysis). Among the 18 tested SNPs, only 2 nsSNP, rs2066965 (R547S) and rs34367357 (V585I), were found to be associated with psoriasis. Furthermore, rs2066965 heterozygous genotype was found to be more prevalent in patients with joint pain. Additionally, the 3D structure of CARD14 protein was predicted using alpha-fold2. NMSim web server was used to perform coarse grind simulations of wild-type CARD14 and two mutated structures. R547S increases protein flexibility, whereas V353I is shown to promote CARD14-induced NF-kappa B activation. This study confirms the association between two CARD14 nsSNPs, rs2066965 and rs34367357 with psoriasis in a Pakistani population, and could be helpful in identifying the role of CARD14 gene variants as potential genetic markers in patients with psoriasis.

Chromosomal Aberrations and Oxidative Stress in Psoriatic Patients with and without Metabolic Syndrome

Psoriasis and metabolic syndrome (MetS), a common comorbidity of psoriasis, are associated with mild chronic systemic inflammation that increases oxidative stress and causes cell and tissue damage. At the cellular level, chromosomal and DNA damage has been documented, thus confirming their genotoxic effect. The main objective of our study was to show the genotoxic potential of chronic inflammation and determine whether the presence of both pathologies increases chromosomal damage compared to psoriasis alone and to evaluate whether there are correlations between selected parameters and chromosomal aberrations in patients with psoriasis and MetS psoriasis. Clinical examination (PASI score and MetS diagnostics according to National Cholesterol Education Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults; NCE/ATPIII criteria), biochemical analysis of blood samples (fasting glucose, total cholesterol, low density and high density lipoproteins; LDL, HDL, non-HDL, and triglycerides;TAG), DNA/RNA oxidative damage, and chromosomal aberration test were performed in 41 participants (20 patients with psoriasis without MetS and 21 with MetS and psoriasis). Our results showed that patients with psoriasis without metabolic syndrome (nonMetS) and psoriasis and MetS had a higher rate of chromosomal aberrations than the healthy population for which the limit of spontaneous, natural aberration was <2%. No significant differences in the aberration rate were found between the groups. However, a higher aberration rate (higher than 10%) and four numerical aberrations were documented only in the MetS group. We found no correlations between the number of chromosomal aberrations and the parameters tested except for the correlation between aberrations and HDL levels in nonMetS patients (rho 0.44; p < 0.02). Interestingly, in the MetS group, a higher number of chromosomal aberrations was documented in non-smokers compared to smokers. Data from our current study revealed an increased number of chromosomal aberrations in patients with psoriasis and MetS compared to the healthy population, especially in psoriasis with MetS, which could increase the genotoxic effect of inflammation and the risk of genomic instability, thus increasing the risk of carcinogenesis.

Probing the Skin–Brain Axis: New Vistas Using Mouse Models

Inflammatory diseases of the skin, including atopic dermatitis and psoriasis, have gained increasing attention with rising incidences in developed countries over the past decades. While bodily properties, such as immunological responses of the skin, have been described in some detail, interactions with the brain via different routes are less well studied. The suggested routes of the skin–brain axis comprise the immune system, HPA axis, and the peripheral and central nervous system, including microglia responses and structural changes. They provide starting points to investigate the molecular mechanisms of neuropsychiatric comorbidities in AD and psoriasis. To this end, mouse models exist for AD and psoriasis that could be tested for relevant behavioral entities. In this review, we provide an overview of the current mouse models and assays. By combining an extensive behavioral characterization and state-of-the-art genetic interventions with the investigation of underlying molecular pathways, insights into the mechanisms of the skin–brain axis in inflammatory cutaneous diseases are examined, which will spark further research in humans and drive the development of novel therapeutic strategies.

Variants in PRKCE and KLC1, Potential Regulators of Type I Psoriasis

Purpose

Psoriasis is a multifactorial disease with a complex genetic predisposition. The pathophysiology of psoriasis is associated with genetic variants. To better characterize gene variants in psoriasis and identify the relationship between clinical characteristics and variant genes in its pathogenesis.

Patients and Methods

DNA was extracted and purified from eight pairs of monozygotic twins with psoriasis discordance and 282 type I psoriasis patients. Thirteen variable genes were amplified and sequenced using the Sanger method after whole genome sequencing.

Results

Thirteen genes were found to be variable in eight pairs of monozygotic twins with psoriasis discordance. Among the 13 genes, the variant frequencies of protein kinase C epsilon (PRKCE) (c.240T>C, 35.9% vs 47.7%, P < 0.05) and kinesin light chain 1 (KLC1) (c.216A>G, 2.9% vs 98.1%, P< 0.01) were significantly lower in psoriasis than in normal Asian individuals. Additionally, we found considerable differences in the relationship between variants in genes CADM2, JPH2, SPTLC3 and clinical characteristics stratified by medical history and family history. Moreover, the variants in MEGF6 (39.52% vs 22.50%, χ²=3.83, p < 0.05) showed a stronger association with the mild group (PASI ≤10) than the heavy group.

Conclusion

Our results provide a comprehensive correlation analysis of regulatory genes that are regulated in psoriasis. This integrated analysis offers novel insight into the pathogenic mechanisms involved in psoriasis.

Systemic pharmacological treatments for chronic plaque psoriasis: a network meta-analysis

BACKGROUND

Psoriasis is an immune-mediated disease with either skin or joints manifestations, or both, and it has a major impact on quality of life. Although there is currently no cure for psoriasis, various treatment strategies allow sustained control of disease signs and symptoms. The relative benefit of these treatments remains unclear due to the limited number of trials comparing them directly head-to-head, which is why we chose to conduct a network meta-analysis.

OBJECTIVES

To compare the efficacy and safety of non-biological systemic agents, small molecules, and biologics for people with moderate-to-severe psoriasis using a network meta-analysis, and to provide a ranking of these treatments according to their efficacy and safety.

SEARCH METHODS

For this update of the living systematic review, we updated our searches of the following databases monthly to October 2021: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of systemic treatments in adults over 18 years with moderate-to-severe plaque psoriasis, at any stage of treatment, compared to placebo or another active agent. The primary outcomes were: proportion of participants who achieved clear or almost clear skin, that is, at least Psoriasis Area and Severity Index (PASI) 90; proportion of participants with serious adverse events (SAEs) at induction phase (8 to 24 weeks after randomisation).

DATA COLLECTION AND ANALYSIS

We conducted duplicate study selection, data extraction, risk of bias assessment and analyses. We synthesised data using pairwise and network meta-analysis (NMA) to compare treatments and rank them according to effectiveness (PASI 90 score) and acceptability (inverse of SAEs). We assessed the certainty of NMA evidence for the two primary outcomes and all comparisons using CINeMA, as very low, low, moderate, or high. We contacted study authors when data were unclear or missing. We used the surface under the cumulative ranking curve (SUCRA) to infer treatment hierarchy, from 0% (worst for effectiveness or safety) to 100% (best for effectiveness or safety).

MAIN RESULTS

This update includes an additional 19 studies, taking the total number of included studies to 167, and randomised participants to 58,912, 67.2% men, mainly recruited from hospitals. Average age was 44.5 years, mean PASI score at baseline was 20.4 (range: 9.5 to 39). Most studies were placebo-controlled (57%). We assessed a total of 20 treatments. Most (140) trials were multicentric (two to 231 centres). One-third of the studies (57/167) had high risk of bias; 23 unclear risk, and most (87) low risk. Most studies (127/167) declared funding by a pharmaceutical company, and 24 studies did not report a funding source. Network meta-analysis at class level showed that all interventions (non-biological systemic agents, small molecules, and biological treatments) showed a higher proportion of patients reaching PASI 90 than placebo. Anti-IL17 treatment showed a higher proportion of patients reaching PASI 90 compared to all the interventions, except anti-IL23. Biologic treatments anti-IL17, anti-IL12/23, anti-IL23 and anti-TNF alpha showed a higher proportion of patients reaching PASI 90 than the non-biological systemic agents. For reaching PASI 90, the most effective drugs when compared to placebo were (SUCRA rank order, all high-certainty evidence): infliximab (risk ratio (RR) 50.19, 95% CI 20.92 to 120.45), bimekizumab (RR 30.27, 95% CI 25.45 to 36.01), ixekizumab (RR 30.19, 95% CI 25.38 to 35.93), risankizumab (RR 28.75, 95% CI 24.03 to 34.39). Clinical effectiveness of these drugs was similar when compared against each other. Bimekizumab, ixekizumab and risankizumab showed a higher proportion of patients reaching PASI 90 than other anti-IL17 drugs (secukinumab and brodalumab) and guselkumab. Infliximab, anti-IL17 drugs (bimekizumab, ixekizumab, secukinumab and brodalumab) and anti-IL23 drugs (risankizumab and guselkumab) except tildrakizumab showed a higher proportion of patients reaching PASI 90 than ustekinumab and three anti-TNF alpha agents (adalimumab, certolizumab and etanercept). Ustekinumab was superior to certolizumab; adalimumab and ustekinumab were superior to etanercept. No significant difference was shown between apremilast and two non-biological drugs: ciclosporin and methotrexate. We found no significant difference between any of the interventions and the placebo for the risk of SAEs. The risk of SAEs was significantly lower for participants on methotrexate compared with most of the interventions. Nevertheless, the SAE analyses were based on a very low number of events with low- to moderate-certainty for all the comparisons (except methotrexate versus placebo, which was high-certainty). The findings therefore have to be viewed with caution. For other efficacy outcomes (PASI 75 and Physician Global Assessment (PGA) 0/1), the results were similar to the results for PASI 90. Information on quality of life was often poorly reported and was absent for several of the interventions.

AUTHORS' CONCLUSIONS

Our review shows that, compared to placebo, the biologics infliximab, bimekizumab, ixekizumab, and risankizumab were the most effective treatments for achieving PASI 90 in people with moderate-to-severe psoriasis on the basis of high-certainty evidence. This NMA evidence is limited to induction therapy (outcomes measured from 8 to 24 weeks after randomisation), and is not sufficient for evaluating longer-term outcomes in this chronic disease. Moreover, we found low numbers of studies for some of the interventions, and the young age (mean 44.5 years) and high level of disease severity (PASI 20.4 at baseline) may not be typical of patients seen in daily clinical practice. We found no significant difference in the assessed interventions and placebo in terms of SAEs, and the safety evidence for most interventions was low to moderate quality. More randomised trials directly comparing active agents are needed, and these should include systematic subgroup analyses (sex, age, ethnicity, comorbidities, psoriatic arthritis). To provide long-term information on the safety of treatments included in this review, an evaluation of non-randomised studies and postmarketing reports from regulatory agencies is needed. Editorial note: This is a living systematic review. Living systematic reviews offer a new approach to review updating, in which the review is continually updated, incorporating relevant new evidence as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Exploration of the Potential Mechanism of the Common Differentially Expressed Genes in Psoriasis and Atopic Dermatitis

Backgrounds. Psoriasis and atopic dermatitis are two common chronic inflammatory skin diseases that enormously deteriorate the psycho-physical and socio-economic condition of the patients. Although differential immune responses have been found to operate in the pathomechanisms of atopic dermatitis and psoriasis, the epidermal keratinocytes are the major targets in both diseases, and sometimes, they show similar clinical presentations. The skin barrier, itching, and inflammation are current and future treatment targets for both of them, but the relevant shared mechanisms of the two diseases are far from understood. Methods. The differential analyses of GSE14905 (psoriasis) and GSE32924 (atopic dermatitis) deposited in GEO database were conducted and obtained their differential expressed genes. Moreover, PPI, functional modules, GO, and KEGG enrichment analyses were used for the further analysis. The mouse models of psoriasis and atopic dermatitis were established, and then, RT-qPCR and Western blotting assay were performed to check the abundant changes of hub genes. Results. There are 732 differentially expressed genes in psoriasis versus nonlesional skin samples. Besides, 611 differentially expressed genes were identified in atopic dermatitis versus nonlesional skin data sets. Based on these differentially expressed genes, we predicted their joint and individual protein-protein interaction networks and functional modules in both psoriasis and atopic dermatitis. Through the PPI network of genes, we calculated the hub nodes and do the GO and KEGG enrichment analysis of overlapped genes of psoriasis and atopic dermatitis, which suggested there were some terms like “positive regulation of interleukin-12 production,” “centromeric region,” and “TNF signaling pathway.” Conclusion. We constructed the predicted PPI networks and functional modules related to psoriasis and atopic dermatitis and distinguished the key candidate target genes CXCL8, STAT1, and MMP9 in the diagnosis and therapy of similar pathogenesis.

Updated Perspectives on Keratinocytes and Psoriasis: Keratinocytes are More Than Innocent Bystanders

Psoriasis is a complex disease triggered by genetic, immunologic, and environmental stimuli. Many genes have been linked to psoriasis, like the psoriasis susceptibility genes, some of which are critical in keratinocyte biology and epidermal barrier function. Still, the exact pathogenesis of psoriasis is unknown. In the disease, the balance between the proliferative and differentiative processes of keratinocytes becomes altered. Multiple studies have highlighted the role of dysregulated immune cells in provoking the inflammatory responses seen in psoriasis. In addition to immune cells, accumulating evidence shows that keratinocytes are involved in psoriasis pathogenesis, as discussed in this review. Although certain immune cell-derived factors stimulate keratinocyte hyperproliferation, activated keratinocytes can also produce anti-microbial peptides, cytokines, and chemokines that can promote their proliferation, as well as recruit immune cells to help initiate and reinforce inflammatory feedback loops. Psoriatic keratinocytes also show intrinsic differences from normal keratinocytes even after removal from the in vivo inflammatory environment; thus, psoriatic keratinocytes have been found to exhibit abnormal calcium metabolism and possible epigenetic changes that contribute to psoriasis. The Koebner phenomenon, in which injury promotes the development of psoriatic lesions, also provides evidence for keratinocytes' contributions to disease pathogenesis. Furthermore, transgenic mouse studies have confirmed the importance of keratinocytes in the etiology of psoriasis. Finally, in addition to immune cells and keratinocytes, data in the literature support roles for other cell types, tissues, and systems in psoriasis development. These other contributors are all potential targets for therapies, suggesting the importance of a holistic approach when treating psoriasis.

Gene Expression Meta-Analysis of Potential Shared and Unique Pathways between Autoimmune Diseases under Anti-TNFα Therapy

While anti-TNFα has been established as an effective therapeutic approach for several autoimmune diseases, results from clinical trials have uncovered heterogeneous patients' response to therapy. Here, we conducted a meta-analysis on the publicly available gene expression cDNA microarray datasets that examine the differential expression observed in response to anti-TNFα therapy with psoriasis (PsO), inflammatory bowel disease (IBD) and rheumatoid arthritis (RA). Five disease-specific meta-analyses and a single combined random-effects meta-analysis were performed through the restricted maximum likelihood method. Gene Ontology and Reactome Pathways enrichment analyses were conducted, while interactions between differentially expressed genes (DEGs) were determined with the STRING database. Four IBD, three PsO and two RA datasets were identified and included in our analyses through our search criteria. Disease-specific meta-analyses detected distinct pro-inflammatory down-regulated DEGs for each disease, while pathway analyses identified common inflammatory patterns involved in the pathogenesis of each disease. Combined meta-analyses further revealed DEGs that participate in anti-inflammatory pathways, namely IL-10 signaling. Our analyses provide the framework for a transcriptomic approach in response to anti-TNFα therapy in the above diseases. Elucidation of the complex interactions involved in such multifactorial phenotypes could identify key molecular targets implicated in the pathogenesis of IBD, PsO and RA.

PSORS1 Locus Genotyping Profile in Psoriasis: A Pilot Case-Control Study

(1) Background: The psoriasis susceptibility 1 (PSORS1) locus, located within the major histocompatibility complex, is one of the main genetic determinants for psoriasis, the genotyping profile for three single-nucleotide polymorphisms (SNPs) comprising the PSORS1 locus: rs1062470 within PSORS1C1/CDSN genes, rs887466 within PSORS1C3 gene, rs10484554 within LOC105375015 gene, were investigated and correlated with psoriasis risk and severity. (2) Methods: This pilot case-controlled study involved 100 psoriatic patients and 100 healthy individuals. We investigated three SNPs and assessed the relative gene expression profile for the PSORS1C1 gene. We then correlated the results with both disease risk and severity. (3) Results: The most significantly associated SNP in PSORS1 locus with psoriasis was rs10484554 with its C/T genotype 5.63 times more likely to develop psoriasis under codominant comparison. Furthermore, C/T and T/T genotypes were 5 times more likely to develop psoriasis. The T allele was 3 times more likely to develop psoriasis under allelic comparison. The relative gene expression of PSORS1C1 for psoriatic patients showed to be under-expressed compared to normal controls. (4) Conclusions: Our study revealed the association of the three studied SNPs with psoriasis risk and severity in an Egyptian cohort, indicating that rs10484554 could be the major key player in the PSORS1 locus.

Psoriasis between Autoimmunity and Oxidative Stress: Changes Induced by Different Therapeutic Approaches

Psoriasis is defined as chronic, immune-mediated disease. Regardless of the development of new therapeutic approaches, the precise etiology of psoriasis remains unknown and speculative. The aim of this review was to systematize the results of previous research on the role of oxidative stress and aberrant immune response in the pathogenesis of psoriasis, as well as the impact of certain therapeutic modalities on the oxidative status in patients with psoriasis. Complex immune pathways of both the innate and adaptive immune systems appear to be major pathomechanisms in the development of psoriasis. Oxidative stress represents another important contributor to the pathophysiology of disease, and the redox imbalance in psoriasis has been reported in skin cells and, systemically, in plasma and blood cells, and more recently, also in saliva. Current immune model of psoriasis begins with activation of immune system in susceptible person by some environmental factor and loss of immune tolerance to psoriasis autoantigens. Increased production of IL-17 appears to be the most prominent role in psoriasis pathogenesis, while IL-23 is recognized as master regulator in psoriasis having a specific role in cross bridging the production of IL-17 by innate and acquired immunity. Other proinflammatory cytokines, including IFN-γ, TNF-α, IL-1β, IL-6, IL-22, IL-26, IL-29, or IL-36, have also been reported to play important roles in the development of psoriasis. Oxidative stress can promote inflammation through several signaling pathways. The most noticeable and most powerful antioxidative effects exert various biologics compared to more convenient therapeutic modalities, such as methotrexate or phototherapy. The complex interaction of redox, immune, and inflammatory signaling pathways should be focused on further researches tackling the pathophysiology of psoriasis, while antioxidative supplementation could be the solution in some refractory cases of the disease.