Genetics of psoriasis: the potential impact on new therapies

An observational study on treatment regimens and effectiveness for psoriasis in real-world settings among 407 patients in Southeast China

Introduction

While new targeted therapies have advanced psoriasis treatment, real-world data on comparative effectiveness is lacking. This study analyzed treatment regimens and response in an observational cohort, examining potential disparities between clinical trials and routine practice.

Methods

Data from the Psoriasis Standardized Diagnosis and Treatment Center registry were analyzed. Patients with ≥1 follow-up were included. Treatment response was assessed using PASI 50/90 criteria. Factors associated with response were analyzed.

Results

407 patients were included (46 first-time diagnosed, 361 previously diagnosed). A higher proportion of first-time diagnosed patients achieved treatment response than previously diagnosed (76.1% vs. 62.6%). Multivariable analysis identified factors associated with reduced response in previously treated patients.

Conclusion

This real-world study found lower treatment response rates compared to clinical trials, especially in previously treated patients. Disparities highlight remaining unmet needs for psoriasis management. Combination and rotational strategies may improve outcomes in patients unresponsive to available therapies. Ongoing research on novel targets and pathways is warranted to address treatment gaps.

Psoriasis and medical ramifications: A comprehensive analysis based on observational meta-analyses

Purpose

Based on a large number of systematic reviews and meta-analyses exploring the relationship between psoriasis and various health outcomes, we conducted an comprehensive analysis to assess the strength and evidence for the association between psoriasis and medical end-point ramifications in patients.

Methods

We searched related meta-analyses, investigating the links between psoriasis and medical ramifications from three databases. All summary effect sizes, 95% CIs, heterogeneity, and small-study effects in the included meta-analyses were recalculated. We assessed the methodological quality of included articles with the AMSTAR 2 tool and graded the epidemiological evidence. Subgroup analysis based on the severity of psoriasis and study design were also performed.

Results

A total of 38 articles comprising 85 unique meta-analyses were included in this study. Although 69 outcomes were statistically significant, only 8 outcomes (nonvascular dementia, ulcerative colitis, pediatric dyslipidemia, gestational diabetes, gestational hypertension, fracture, multiple sclerosis, and schizophrenia) showed a high quality of epidemiological evidence.

Conclusion

We found that psoriasis increased the risk of 69 health outcomes, and 8 outcomes were graded as high-quality evidence. No evidence was found that psoriasis was beneficial for any medical end point. However, to verify our results, more large-sample, multi-center prospective cohort studies are needed.

Nanotechnology-based medicinal products and patents: a promising way to treat psoriasis

Psoriasis is an autoimmune skin disorder that is characterised by chronic inflammation and erythematous scaly patches. It has a significant impact on the patient's quality of life and can cause psychological stress. There are several aspects which cause psoriasis for instance, environmental issues, immune disorders, bacterial infections, and genetic issues. Plentiful therapeutic means or treatments are accessible, but not any of them can completely and effectively cure psoriasis without hindering patient compliance. Hence, it becomes challenging to discover a new drug moiety or any drug delivery method to cure psoriasis. Conventional treatment of psoriasis involves anti-inflammatory agents, immune suppressants, phototherapy, and biologic treatment, those were given in different forms such as topical, oral, or systemic formulations, but these all were unsuccessful to accomplish complete reduction of psoriasis as well as causing adverse side effects. In terms of dose frequency, doses, efficacy, and side effects, nanotechnology-based new formulations are the most promising prospects for addressing the challenges and limits associated with present psoriasis formulations. Hence, our major goal of this review is to present various advanced nanotechnological approaches for effective topical treatment of psoriasis. In short, nano-formulations continue to be formed as very promising modality in the treatment of psoriasis as they suggest improved penetration, targeted delivery, increased safety, and efficacy.

Tumor Necrosis Factor-α 308 G/A polymorphism and psoriasis risk: A pooled analysis in different populations

More and more researches have been carried out on the association between the tumor necrosis factor-α (TNF-α) 308 G/A polymorphism and psoriasis, however, controversial results have emerged in these studies. This meta-analysis was performed to quantitatively clarify the relationship between TNF-α 308 G/A polymorphism and the risk of psoriasis in different populations. Databases of PubMed, Springer Link, Ovid, Chinese Wanfang Data Bases, Chinese National Knowledge Infrastructure and Chinese Biology Medicine were investigated until June 2019. The association between the TNF-α 308 G/A polymorphism and psoriasis was evaluated by calculating the pooled odds ratio (OR) and 95% confidence intervals (CIs). A total of 26 studies including 3657 patients and 3197 controls were screened out. In the overall population, the pooled results showed a reduced psoriasis risk with the TNF-α 308 G/A polymorphism (A vs G: OR = 0.77, 95% CI = 0.67-0.89; AA+GA vs GG: OR = 0.72, 95% CI = 0.61-0.86). In the subgroup analysis stratified by geographic locations, the TNF-α 308 G/A polymorphism was significantly associated with a reduced risk of psoriasis in Germany (A vs G: OR = 0.67, 95% CI = 0.57-0.78; AA+GA vs GG: OR = 0.62, 95% CI = 0.52-0.75), as well as in China (AA+GA vs GG: OR = 0.71, 95% CI = 0.52-0.98) and Poland (A vs G: OR = 0.61, 95% CI = 0.38-0.97; AA+GA vs GG: OR = 0.59, 95% CI = 0.35-0.99). This study indicated a significantly reduced psoriasis risk associated with the TNF-α 308 G/A polymorphism in Germans, as well as in Chinese and Poles populations compared with other populations. Ethnicity and geographic locations probably play a pivotal role in the genetic association of psoriasis.

Emerging systemic drugs in the treatment of plaque psoriasis

INTRODUCTION

Psoriasis is a common, chronic inflammatory skin condition that affects 2-3% of the US population and represents a large psychosocial burden for patients. Over the last decade, highly effective targeted therapies for psoriasis have been developed - namely, those targeting interleukin (IL)-17 and IL-23. The success of biologic agents targeting IL-17 and IL-23 underscores the importance of the IL-23/T helper (Th)17 cell axis in psoriasis pathogenesis. Oral small molecule drugs - such as Janus kinase (JAK) inhibitors, tyrosine kinase 2 (TYK2) inhibitors, and fumaric acid esters (FAEs) - are also being investigated for the treatment of psoriasis.

AREAS COVERED

This article reviews systemic biologic and oral small molecule drugs currently undergoing clinical trials for the treatment of plaque psoriasis.

EXPERT OPINION

Many patients with psoriasis have mild disease, and many with mild disease do not seek medical care for their condition. Many patients with mild disease could be adequately treated with topical treatments and phototherapy; however, adherence and feasibility have often been an issue with these treatment types. There seems to be limited room for development of novel biologics, as the existing ones are extraordinarily safe, effective, and convenient with few injections. Patients would prefer a safe, effective oral treatment; however, JAK inhibitors seem unlikely to fill this role completely.

A Meta-Analysis of the Relationship between Tumor Necrosis Factor-α Polymorphisms and Psoriasis

BACKGROUND

Some previous studies already explored associations between tumor necrosis factor-α (TNF-α) polymorphisms and psoriasis, with conflicting findings. Here, we aimed to better analyze the relationship between TNF-α polymorphisms and psoriasis in a larger pooled population by performing a meta-analysis.

METHODS

We searched Pubmed, Embase, Web of Science and CNKI for related articles. We calculated OR and 95% CI to estimate whether there are genetic associations between TNF-α polymorphisms and psoriasis.

RESULTS

Twenty-nine studies were included for this meta-analysis. TNF-α-238 G/A (dominant comparison: OR 0.44, 95% CI 0.34-0.59; recessive comparison: OR 1.63, 95% CI 1.03-2.57; overdominant comparison: OR 2.21, 95% CI 1.71-2.85; allele comparison: OR 0.48, 95% CI 0.36-0.62) and -857 C/T (dominant comparison: OR 0.58, 95% CI 0.41-0.80; overdominant comparison: OR 1.58, 95% CI 1.12-2.23; allele comparison: OR 0.62, 95% CI 0. 0.47-0.82) polymorphisms were found to be significantly associated with psoriasis in the general population. Subgroup analyses indicated that the -238 G/A polymorphism was significantly associated with psoriasis in Caucasians and East Asians, the -308 G/A polymorphism was significantly associated with psoriasis in East Asians, and the -857 C/T polymorphism was significantly associated with psoriasis in Caucasians.

CONCLUSIONS

TNF-α -238 G/A, -308 G/A and -857 C/T polymorphisms could be used to identity individuals with elevated susceptibility to psoriasis in certain populations.

Patients with psoriasis have a higher risk of schizophrenia: A systematic review and meta-analysis of observational studies

Background and Objectives

Patients with psoriasis are known to be at a higher risk of several comorbidities, but little is known about their risk of developing schizophrenia.

Methods

A systematic review and meta-analysis of cohort and case-control studies that reported relative risk, hazard ratio, odds ratio (OR), or standardized incidence ratio comparing risk of schizophrenia in patients with psoriasis versus subjects without psoriasis was conducted. Pooled OR and 95% confidence interval were calculated using random-effect, generic inverse-variance methods of DerSimonian and Laird.

Results

A total of five studies (one retrospective cohort study and four case-control studies) with more than 6 million participants met the eligibility criteria and were included in this meta-analysis. The pooled OR of schizophrenia in patients with psoriasis versus subjects without psoriasis was 1.41 (95% confidence interval, 1.19-1.66). The statistical heterogeneity was low with an I2 of 33%.

Conclusion

This systematic review and meta-analysis demonstrated a significantly increased risk of schizophrenia among patients with psoriasis.

RETRACTED: NFKB1 mediates Th1/Th17 activation in the pathogenesis of psoriasis

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor and the authors, following concerns raised in the public domain. The authors informed the journal that they had found that the psoriasis model panel and the vector panel of Fig 4D were duplicated. The authors think that the relevant results are not sufficient to support the conclusions drawn from this study.

Profile of Tumour Necrosis Factor Alpha -308 G/A Gene Polymorphism in Psoriatic Patients in Karnataka, India

INTRODUCTION

Tumour necrosis factor-alpha (TNFα) gene -308G/A polymorphism (rs1800629) are associated with psoriasis in several populations worldwide. Presently, there is no literature on the status of this polymorphism in the South Indian population.

AIM

To determine the profile of TNFα -308G/A polymorphism among psoriatic patients.

MATERIALS AND METHODS

This case-control study involved 74 patients with Psoriasis Vulgaris (PsV) and 74 age and gender matched healthy individuals. Patients were recruited from the Department of Dermatology of R.L. Jalappa Hospital and Research Center, Tamaka, Kolar, Karnataka, India, from March 2014 to March 2016. TNFα -308G/A polymorphism was genotyped by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) method.

RESULTS

The frequency of TNFα -308A allele 7.4% among psoriatic and 8.8% among non-psoriatic individuals. The difference was not statistically significant (p=0.82).

CONCLUSION

Our results indicate that TNFα gene -308G/A polymorphism is not a significant marker for the risk of developing PsV among South Indian (Karnataka) psoriatic patients.

Tumor necrosis factor alpha gene promoter -238G/A polymorphism increases the risk of psoriasis vulgaris in Indian patients

BACKGROUND

Tumor necrosis factor alpha (TNFα) gene -238G/A polymorphism (rs361525) is associated with psoriasis in several populations worldwide. To the best of our knowledge, there is no information about this polymorphism in Indian psoriatic patients. This study was undertaken to fill the gap in knowledge.

METHODS

This case-control study involved 72 patients with psoriasis vulgaris (PsV) and 72 age and gender matched healthy individuals. TNFα -238G/A polymorphism was genotyped by PCR-RFLP method.

RESULTS

TNFα -238A allele was 5 times commoner in PsV patients than in the control group (P = 4.1 × 10^-7 ; odds ratio [OR] = 6.5 [0.95 CI: 2.9-14.6]). Distribution of the genotypes in the two groups showed statistically significant difference in dominant genetic model (P = 2.3 × 10^-7 ) and not in recessive genetic model (P = 2.5 × 10^-1 ). Odds ratio for the occurrence of -238A genotype in PsV patients was 8.8 (0.95 CI: 3.5-20.2). The association showed no major difference when PsV patients were subgrouped into type I and type II categories and tested separately. Subgroup analysis on the basis of disease severity showed higher association with the moderate-severe subgroup (P = 2.4 × 10^-9 , OR 15.4 [0.95 CI: 5.8-41.0]) than with mild subgroup (P = 1.3 × 10^-2 , OR 3.8 [0.95 CI: 1.3-10.9]).

CONCLUSIONS

Our results indicate that TNFα gene -238G/A polymorphism increases the risk of developing psoriasis vulgaris among Indians. Also, the data show that severity and not the type affects the strength of association in this population.

A brief summary of clinical types of psoriasis

Psoriasis is a chronic inflammatory dermatosis that is thought to onset as a result of T lymphocyte-mediated immunological response. Disease may manifest itself in different modalities with regard to clinical features and severity. Clinical type of psoriasis is an important element in determining the therapy regimen. This article reviews clinical types of psoriasis.

HLA-C and TNF gene polymorphisms are associated with psoriasis in Brazilian patients

BACKGROUND

Polymorphisms at the human leukocyte antigens (HLA-C) and tumor necrosis factor (TNF) genes have been associated with susceptibility to psoriasis in several worldwide populations. In this study, HLA-C and TNF (-238/-308) polymorphisms were performed in 125 Brazilian patients and 202 healthy controls.

METHODS

HLA-C and TNF promoter region alleles were typed by polymerase chain reaction using sequence-specific primer-polymerase chain reaction.

RESULTS

The presence of HLA-C*06 was associated with psoriasis onset, particularly in younger patients, being more frequent for patients with disease onset before the age of 20 years (P = 0.03), 25 years (P = 0.01), or 30 years (P = 0.03). No association between HLA-C*06 and psoriasis was observed for patients older than 35 years. Susceptibility to psoriatic arthritis was associated with the TNF -238 G/A genotype (P = 0.02). The TNF -308A allele was overrepresented in patients (P = 0.0061), and the TNF -308 G/A genotype was increased in generalized forms (erythrodermic and generalized pustular psoriasis) compared to plaque psoriasis (P < 0.001). The TNF -238A/HLA-C*06 haplotype was overrepresented in patients (P = 0.025), while the TNF -238G/HLA-C*15 haplotype was increased in controls (P = 0.037).

CONCLUSIONS

The strong association of HLA-C*06 allele with disease susceptibility, particularly in early onset psoriasis, indicates that younger ages could be considered to stratify psoriasis into early and late types. TNF -308 polymorphisms can be associated with psoriasis susceptibility and severity. Potential genetic markers of psoriasis in populations with a complex mixture of ethnicities should be investigated.

Whole-exome SNP array identifies 15 new susceptibility loci for psoriasis

Genome-wide association studies (GWASs) have reproducibly associated ∼40 susceptibility loci with psoriasis. However, the missing heritability is evident and the contributions of coding variants have not yet been systematically evaluated. Here, we present a large-scale whole-exome array analysis for psoriasis consisting of 42,760 individuals. We discover 16 SNPs within 15 new genes/loci associated with psoriasis, including C1orf141, ZNF683, TMC6, AIM2, IL1RL1, CASR, SON, ZFYVE16, MTHFR, CCDC129, ZNF143, AP5B1, SYNE2, IFNGR2 and 3q26.2-q27 (P<5.00 × 10(-08)). In addition, we also replicate four known susceptibility loci TNIP1, NFKBIA, IL12B and LCE3D-LCE3E. These susceptibility variants identified in the current study collectively account for 1.9% of the psoriasis heritability. The variant within AIM2 is predicted to impact protein structure. Our findings increase the number of genetic risk factors for psoriasis and highlight new and plausible biological pathways in psoriasis.

What have we learned about non-involved psoriatic skin from large-scale gene expression studies?

Psoriasis is a chronic inflammatory skin disorder; its genetic background has been widely studied in recent decades. Recognition of novel factors contributing to the pathogenesis of this disorder was facilitated by potent molecular biology tools developed during the 1990s. Large-scale gene expression studies, including differential display and microarray, have been used in experimental dermatology to a great extent; moreover, skin was one of the first organs analyzed using these methods. We performed our first comprehensive gene expression analysis in 2000. With the help of differential display and microarray, we have discovered several novel factors contributing to the inherited susceptibility for psoriasis, including the EDA+ fibronectin splice variant and PRINS. The long non-coding PRINS RNA is expressed at higher levels in non-involved skin compared to healthy and involved psoriatic epidermis and might be a factor contributing cellular stress responses and, specifically, to the development of psoriatic symptoms. This review summarizes the most important results of our large-scale gene expression studies.

An epidemiological study on trigger factors and quality of life in psoriatic patients

Objective:

to evaluate the role of stress, tobacco, drugs, infections, allergies, heredity, alcohol, hormones and skin aggressions as trigger factors and the impact on quality of life in a sample of psoriasis patients.

Methods:

a transversal study performed in 90 patients affected by psoriasis between January and November 2012 at the “Nene Tereza” University Hospital, Tirane, Albania, based on two scored questionnaires.

Results:

more than 70 % of patients reported that stressful events caused a flare- up of their psoriasis (p< 0.05). More than 60% of males and 20% of females were smokers (p< 0.05). About 20% of our patients were taking one or more of the medications listed in the questionnaire (p> 0.05). About 20% of patients reported having had recurrent infections (p<0,05). About 80% of males patients consumed alcohol (p<0,05). More than 40% reported a relative with psoriasis. Statistical comparison of the group that reported skin aggressions with the group that did not revealed a significant difference (p<0,05). Only a few of them reported to have allergies (p>0,05). About 36% of females reported that hormonal changes (puberty and menopause) exacerbated their psoriasis (p<0,05). More than 40% of patients reported that psoriasis seriously affects their quality of life.

Conclusion:

stress, tobacco, infections, heredity, alcohol, hormonal changes and skin aggressions were confirmed as trigger factors for psoriasis in the present sample. Allergies and the investigated drugs seemed not to have any influence in flare-ups. We found that psoriasis had a serious impact in the quality of life in over of 40% of the patients interviewed.

Apolipoprotein E gene polymorphism and serum lipid profile in Saudi patients with psoriasis

Background/Aim. Apolipoprotein E (APOE) gene variants have been reported to influence psoriasis risk. However, data is limited to a few ethnicities and no similar study has been performed in middle eastern populations. We investigated this association in Saudi psoriasis patients. Methods. Saudi subjects (294) were genotyped for APOE gene using APOE StripAssay kit. Results. The frequencies of alleles ε2, ε4, and genotypes ε3/ε4 and ε3/ε2 were significantly higher in psoriasis patients compared with those in controls. The frequency of ε3 allele and ε3/ε3 genotype was significantly lower in patients. Other genotypes, ε2/ε4, ε2/ε2, and ε4/ε4, were absent in both groups. The serum cholesterol, triglycerides, and LDL levels were significantly higher in psoriasis patients contrary to HDL level. Patients with APOE ε4 had significantly higher levels of total cholesterol and LDL cholesterol, whereas those with the ε2 had higher HDL cholesterol, and triglycerides. Conclusion. APOE alleles ε2, ε4, and genotypes ε2/ε3 and ε4/ε3 are associated with psoriasis and can be a risk factor while allele ε3 and genotype ε3/ε3 may be protective for psoriasis in Saudis. Results of lipid profile support that psoriasis is one of the independent risk factors for hyperlipidemia and emphasize the need of screening cardiovascular diseases in psoriatic patients.

Copy number variations in IL22 gene are associated with Psoriasis vulgaris

Psoriasis vulgaris (PsV) is a frequent, chronically relapsing, immune-mediated systemic disease with characteristic skin changes. IL22 is a cytokine of IL10 family, with significant proliferative effect on different cell lines. Copy number variations (CNV) have been discovered to have phenotypic consequences and are associated with various types of diseases. In the work presented here we analyzed the copy number variations in IL22 gene of exon1 and exon5. Our results showed that the IL22 gene exon1 was significantly associated with psoriasis severity (P<0.0001). However, the association between IL22 gene exon5 copy numbers and psoriasis was not detected.

Bioengineered skin humanized model of psoriasis

This protocol describes the generation of a skin humanized mouse model for psoriasis using bioengineering approaches. This method is relatively simple, highly reproducible and ensures the obtention of a large and homogenous number of engrafted animals bearing a portion of human skin with psoriatic phenotype. The technique can employ cells from skin biopsies and blood samples from non-related healthy human donors (allogeneic version), as well as skin and blood cells from psoriatic patients (autologous version). In both cases, the psoriatic phenotype was developed after intradermal administration of in vitro derived T1 lymphocytes along with Th17 recombinant cytokines, in conjunction with mild barrier disruption by tape-stripping. This skin-humanized model for psoriasis emerges as a powerful tool to study the mechanisms underlying the pathogenesis of the disease. More importantly, the feasibility of the system may allow the evaluation of different therapeutic compounds in an in vivo system, employing local and/or systemic administration.

Cathelicidin LL-37: a defense molecule with a potential role in psoriasis pathogenesis

Epidermal keratinocytes produce and secrete antimicrobial peptides (AMPs) that subsequently form a chemical shield on the skin surface. Cathelicidins are one family of AMPs in skin with various further immune functions. Consequently, dysfunction of these peptides has been implicated in the pathogenesis of inflammatory skin disease. In particular, the cathelicidin LL-37 is overexpressed in inflamed skin in psoriasis, binds to extracellular self-DNA released from dying cells and converts self-DNA in a potent stimulus for plasmacytoid dendritic cells (pDCs). Subsequently, pDCs secrete type I interferons and trigger an auto-inflammatory cascade. Paradoxically, therapies targeting the vitamin D pathway such as vitamin D analogues or UVB phototherapy ameliorate cutaneous inflammation in psoriasis but strongly induce cathelicidin expression in skin at the same time. Current evidence now suggests that self-DNA present in the cytosol of keratinocytes is also pro-inflammatory active and triggers IL-1β secretion in psoriatic lesions through the AIM2 inflammasome. This time, however, binding of LL-37 to self-DNA neutralizes DNA-mediated inflammation. Hence, cathelicidin LL-37 shows contrasting roles in skin inflammation in psoriasis and might serve as a target for novel therapies for this chronic skin disease.

Genome-wide meta-analysis of psoriatic arthritis identifies susceptibility locus at REL

Psoriatic arthritis (PsA) is a chronic inflammatory musculoskeletal disease affecting up to 30% of psoriasis vulgaris (PsV) cases and approximately 0.25% to 1% of the general population. To identify common susceptibility loci, we performed a meta-analysis of three imputed genome-wide association studies (GWAS) on psoriasis, stratified for PsA. A total of 1,160,703 SNPs were analyzed in the discovery set consisting of 535 PsA cases and 3,432 controls from Germany, the United States and Canada. We followed up two SNPs in 1,931 PsA cases and 6,785 controls comprising six independent replication panels from Germany, Estonia, the United States and Canada. In the combined analysis, a genome-wide significant association was detected at 2p16 near the REL locus encoding c-Rel (rs13017599, P=1.18×10⁻⁸, OR=1.27, 95% CI=1.18–1.35). The rs13017599 polymorphism is known to associate with rheumatoid arthritis (RA), and another SNP near REL (rs702873) was recently implicated in PsV susceptibility. However, conditional analysis indicated that rs13017599, rather than rs702873, accounts for the PsA association at REL. We hypothesize that c-Rel, as a member of the Rel/NF-κB family, is associated with PsA in the context of disease pathways that involve other identified PsA and PsV susceptibility genes including TNIP1, TNFAIP3 and NFκBIA.

Serum prolactin levels in psoriasis and correlation with cutaneous disease activity

BACKGROUND

Prolactin (PRL), a neuropeptide secreted by the anterior pituitary gland, possesses a variety of physiological actions. It has been implicated as an important immunomodulator and exerts a proliferative effect in cultured human keratinocytes via specific receptors. Some studies have indicated an increase in serum PRL levels in psoriasis and exacerbation of psoriasis when a prolactinoma is present.

AIM

To evaluate the correlation between serum PRL levels and Psoriasis Area and Severity Index (PASI).

METHODS

Serum PRL levels were measured in 20 patients (10 mean, 10 women, age range 18-88 years) with plaque-type psoriasis before and after a 6-week period of topical treatment with tacalcitol ointment. Results were compared with a group of 20 healthy volunteers.

RESULTS

Serum PRL levels were significantly increased in the psoriatic group compared with the control group (P < 0.001) and were significantly reduced after treatment (P = 0.001). There was a correlation between pretreatment serum PRL levels and PASI (r = 0.33; P = 0.02).

CONCLUSIONS

These results indicate that serum PRL levels may serve as a biological marker of psoriatic disease activity.

The genetic factors in aetiology and pathogenesis of psoriasis

The results of genealogical and molecular-genetic assays of 250 patients with psoriasis are represented. The markers of increased and decreased risk of developing psoriasis have been detected; a multifactorial nature of the disease has been documented.

Comparative assessment of biologics in treatment of psoriasis: drug design and clinical effectiveness of ustekinumab

The development of psoriasis and psoriatic arthritis is a multistep process that leads to chronic or recurrent inflammation. Recent studies have suggested the importance of T helper (TH)1 and TH17 cells, accessory cells, and proinflammatory cytokines in the pathogenesis of the enthesis, synovium, and skin involvement in psoriasis in the presence of susceptibility genes that remain quiescent until triggered. Biologics, such as soluble CTLA-4 immunoglobulin, tumor necrosis factor (TNF) inhibitors, and ustekinumab, inhibit T cell activation which eventually leads to further stimulation of the interleukin 12, 17, and 23 axis, TNF-α, and lymphotoxin-α. Treatment with TNF-α blockers has been effective in refractory psoriasis and psoriatic arthritis, but there is still a subgroup of patients who do not respond to TNF inhibitors and, paradoxically, when treated, may develop TNF-induced psoriasis. Ustekinumab, because of its different mechanism of action at the level of the interleukin 12, 17, and 23 pathways, is an alternative treatment for this group of patients.

Genome-wide association study identifies a psoriasis susceptibility locus at TRAF3IP2

Psoriasis is a multifactorial skin disease characterized by epidermal hyperproliferation and chronic inflammation, the most common form of which is psoriasis vulgaris (PsV). We present a genome-wide association analysis of 2,339,118 SNPs in 472 PsV cases and 1,146 controls from Germany, with follow-up of the 147 most significant SNPs in 2,746 PsV cases and 4,140 controls from three independent replication panels. We identified an association at TRAF3IP2 on 6q21 and genotyped two SNPs at this locus in two additional replication panels (the combined discovery and replication panels consisted of 6,487 cases and 8,037 controls; combined P = 2.36 × 10⁻¹⁰ for rs13210247 and combined P = 1.24 × 10⁻¹⁶ for rs33980500). About 15% of psoriasis cases develop psoriatic arthritis (PsA). A stratified analysis of our datasets including only PsA cases (1,922 cases compared to 8,037 controls, P = 4.57 × 10⁻¹² for rs33980500) suggested that TRAF3IP2 represents a shared susceptibility for PsV and PsA. TRAF3IP2 encodes a protein involved in IL-17 signaling and which interacts with members of the Rel/NF-κB transcription factor family.

Current concepts in the pathogenesis of psoriasis

Psoriasis is a multi-factorial skin disease with a complex pathogenesis. Various factors which have been suggested to play a key role in the pathogenesis are T cells, antigen presenting cells (APC's), keratinocytes, Langerhans' cells, macrophages, natural killer cells, an array of Th1 type cytokines, certain growth factors like vascular endothelial growth factor (VEGF), keratinocyte growth factor (KGF), and others. It has been hypothesized that the disease starts with the activation of T cell by an unknown antigen, which leads to secretion of an array of cytokines by activated T cells, inflammatory cells, and keratinocytes. The characteristic lesion of psoriasis is due to the hyper-proliferation of the keratinocyte. Activated Langerhans' cells migrate from skin to lymph nodes presenting the antigen to nodal naïve T cells (cells that have not been activated by antigen previously). The T cells activated by non-antigen-dependent mechanism may, however, become antigen-specific memory cells that react with a cross-reactive auto-antigen such as keratin (molecular mimicry). The genetic background of the disease may be suggested from the fact that concordance rate is 63–73% in monozygotic twins, as compared to 17–20% in dizygotic twins. Several disease susceptibility loci have been suggested as predisposing factors, PSORS1-PSORS9.

Characterisation of psoriasis susceptibility locus 6 (PSORS6) in patients with early onset psoriasis and evidence for interaction with PSORS1

BACKGROUND

Psoriasis is a genetically complex, chronic inflammatory skin disease. The authors have previously identified a susceptibility locus on chromosome 19p13 (PSORS6).

METHODS AND RESULTS

In a follow-up linkage disequilibrium (LD) study in an independent family based cohort, the authors found evidence for association to a newly discovered microsatellite at this locus (D19SPS21, p<5.3x10(-5)). An LD based association scan in 300 trios revealed association to several single, single nucleotide polymorphisms (SNPs) in one LD block. When the authors stratified this cohort for carrying the PSORS1 risk allele at the HLA-C locus, evidence for association became much stronger at single SNP and haplotype levels (p values between 1.0x10(-4) and 8.0x10(-4)). In a replication study of 1114 patients and 937 control individuals, evidence for association was also observed after stratification to the PSORS1 risk allele. In both study groups, logistic regression showed evidence for interaction between the risk alleles at PSORS1 and PSORS6. Best p values for rs12459358 in both study groups remained significant after correction for multiple testing. The associated LD block did not comprise any known genes. Interestingly, an adjacent gene, MUC16, coding for a large glycosylated protein expressed in epithelia and of unknown function, could be shown to be also expressed in tissues relevant for pathogenesis of psoriasis such as skin and thymus. Immunohistochemical analyses of skin revealed focal staining for MUC16 in suprabasal epidermal cells. Further functional studies are required to clarify its potential role in psoriasis and identify the causal variant(s) at this locus.

CONCLUSION

The data establish PSORS6 as a confirmed psoriasis susceptibility locus showing interaction with PSORS1.

A 9-centimorgan interval of chromosome 10 controls the T cell-dependent psoriasiform skin disease and arthritis in a murine psoriasis model

Psoriasis is a complex genetic disease of unresolved pathogenesis with both heritable and environmental factors contributing to onset and severity. In addition to a disfiguring skin inflammation, approximately 10-40% of psoriasis patients suffer from destructive joint involvement. Previously, we reported that the CD18 hypomorphic PL/J mouse carrying a mutation resulting in reduced expression of the common chain of beta(2) integrins (CD11/CD18) spontaneously develops a skin disease that closely resembles human psoriasis. In contrast, the same mutation on C57BL/6J background did not demonstrate this phenotype. By a genome-wide linkage analysis, two major loci were identified as contributing to the development of psoriasiform dermatitis under the condition of low CD18 expression. Using a congenic approach, we now demonstrate that the introduction of a 9-centimorgan fragment of chromosome 10 derived from the PL/J strain into the disease-resistant CD18 hypomorphic C57BL/6J was promoting the development of psoriasiform skin disease and notably also arthritis. We therefore designated this locus psoriasiform skin disease-associated locus 1 (PSD1). High numbers of CD4(+) T cells and TNF-alpha producing macrophages were detected both in inflamed skin and joints in these congenic mice, with a complete resolution upon TNF-alpha inhibitor therapy or depletion of CD4(+) T cells. For the first time, we have identified a distinct genetic element that contributes to the T cell-dependent development of both psoriasiform skin disease and associated arthritis. This congenic model will be suitable to further investigations of genetic and molecular pathways that cause psoriasiform dermatitis and arthritis, and it may also be relevant for other autoimmune diseases.

Psoriasis and pentoxifylline: a clinical, histopathologic, and immunohistochemical evaluation

OBJECTIVE

The aim of this study was to examine the clinical and histopathologic effects of pentoxifylline on psoriasis, compared with placebo.

METHODS

Sixty-one outpatients with active psoriasis were randomly assigned to either of 2 groups: one was given pentoxifylline 400 mg tid PO, and the other, placebo. Fifty-six patients concluded the study. They were evaluated clinically and by laboratory parameters before and after 8 weeks of treatment. Pretreatment and posttreatment biopsies were taken. Initial sections were stained with hematoxylin-eosin. Further cuts were immunostained for cytokeratins 10, 14, and 16.

RESULTS

Clinical and histologic improvement did not show statistically significant differences between the groups. No laboratory abnormalities or serious reactions related to the drug were observed.

CONCLUSIONS

No statistical difference was seen when the treatment group was compared with the control group. Pentoxifylline is a well tolerated and safe drug, but its efficacy in psoriasis appears to be limited.

Identification of Susceptibility Loci for Skin Disease in a Murine Psoriasis Model

Psoriasis is a frequently occurring inflammatory skin disease characterized by thickened erythematous skin that is covered with silvery scales. It is a complex genetic disease with both heritable and environmental factors contributing to onset and severity. The CD18 hypomorphic PL/J mouse reveals reduced expression of the common chain of beta(2) integrins (CD11/CD18) and spontaneously develops a skin disease that closely resembles human psoriasis. In contrast, CD18 hypomorphic C57BL/6J mice do not demonstrate this phenotype. In this study, we have performed a genome-wide scan to identify loci involved in psoriasiform dermatitis under the condition of low CD18 expression. Backcross analysis of a segregating cross between susceptible CD18 hypomorphic PL/J mice and the resistant CD18 hypomorphic C57BL/6J strain was performed. A genome-wide linkage analysis of 94 phenotypically extreme mice of the backcross was undertaken. Thereafter, a complementary analysis of the regions of interest from the genome-wide screen was done using higher marker density and further mice. We found two loci on chromosome 10 that were significantly linked to the disease and interacted in an additive fashion in its development. In addition, a locus on chromosome 6 that promoted earlier onset of the disease was identified in the most severely affected mice. For the first time, we have identified genetic regions associated with psoriasis in a mouse model resembling human psoriasis. The identification of gene regions associated with psoriasis in this mouse model might contribute to the understanding of genetic causes of psoriasis in patients and pathological mechanisms involved in development of disease.

Does Inflammatory Linear Verrucous Epidermal Nevus Represent a Segmental Type 1/Type 2 Mosaic of Psoriasis?

BACKGROUND

A 6-year-old girl with a symmetric linear eruption on both of her legs, clinically and histologically resembling inflammatory linear verrucous epidermal nevus (ILVEN) or linear psoriasis (LP), with concomitant psoriasis of the guttata type and a positive family history of psoriasis is presented. The questions as to whether LP actually exists and ILVEN represents a distinct entity are still under debate.

OBJECTIVE AND METHODS

The recent literature concerning case reports of ILVEN and LP is reviewed.

RESULTS

Case reports of ILVEN and LP can be subdivided into four different groups: (1) ILVEN with or without concomitant psoriasis, only in part reacting to antipsoriatic treatment, (2) ILVEN without concomitant psoriasis, (3) LP with concomitant psoriasis vulgaris, with both groups 2 and 3 reacting successfully to antipsoriatic treatment, and (4) LP without concomitant psoriasis vulgaris and with no family history of psoriasis (very rarely reported).

CONCLUSION

It is hypothesized that inflammatory linear verrucous eruption besides nevoid psoriasis/LP represents a further segmental type 1/type 2 mosaic of psoriasis which, if a (verrucous) epidermal nevus exists, shows a high affinity of occurrence in close context to such a nevus. Heritability is thought to be possible.

The role of interleukin-12 in the pathogenesis of psoriasis

OBJECTIVES

To verify the role of IL-12 in the pathogenesis of psoriasis and determine its relation to IFNgamma.

DESIGN AND METHODS

Skin biopsies from lesional and non-lesional skin of 30 patients and 10 healthy controls were obtained for quantitative PCR examination of IL-12 (P40) and IFNgamma mRNA as well as in situ PCR of IL-12 (P40) and IFNgamma mRNA.

RESULTS

IL-12 and IFNgamma levels were higher in lesional skin than in non-lesional and control skin. A significant correlation between IL-12 and IFNgamma was found. By in situ PCR hybridization, IL-12 expression was only found in the dermis, while IFNgamma was invariably expressed in the dermis and/or epidermis.

CONCLUSION

We suggest that IL-12 independently and through IFNgamma induction may have a crucial role in the development of the active psoriatic lesion itself, where it is probably produced locally in the dermis as a step in the evolution of the psoriatic lesion.

Psoriasis--recent advances in understanding its pathogenesis and treatment

Although not completely understood, there is clearly a genetic component in the development of psoriasis. Twin studies show a 67% concordance for monozygotic twins versus 18% for dizygotic twins. This lack of complete concordance in monozygotic twins suggests multifactorial inheritance and interaction between genetic predisposition and the environment. At present, 8 different psoriasis susceptibility loci have been identified in genome-wide linkage scans, including locations on 15 different chromosomes. Genetic connections have been made between psoriasis and other diseases, including atopic dermatitis, rheumatoid arthritis, and Crohn's disease. A variety of approaches are available for the treatment of psoriasis, ranging from topical agents for milder forms of the disease to phototherapy and systemic agents for severe psoriasis. Despite the importance of systemic therapies and recent advances represented by biologic agents, topical treatments will probably remain the mainstay of psoriasis therapy for most patients. The advent of new, cosmetically attractive vehicles may enhance compliance, add to the use of topical agents, and potentially improve patient outcomes.

Identification and characterization of a novel, psoriasis susceptibility-related noncoding RNA gene, PRINS

To identify genetic factors contributing to psoriasis susceptibility, gene expression profiles of uninvolved epidermis from psoriatic patients and epidermis from healthy individuals were compared. Besides already characterized genes, we identified a cDNA with yet unknown functions, which we further characterized and named PRINS (Psoriasis susceptibility-related RNA Gene Induced by Stress). In silico structural and homology studies suggested that PRINS may function as a noncoding RNA. PRINS harbors two Alu elements, it is transcribed by RNA polymerase II, and it is expressed at different levels in various human tissues. Real time reverse transcription-PCR analysis showed that PRINS was expressed higher in the uninvolved epidermis of psoriatic patients compared with both psoriatic lesional and healthy epidermis, suggesting a role for PRINS in psoriasis susceptibility. PRINS is regulated by the proliferation and differentiation state of keratinocytes. Treatment with T-lymphokines, known to precipitate psoriatic symptoms, decreased PRINS expression in the uninvolved psoriatic but not in healthy epidermis. Real time reverse transcription-PCR analysis showed that stress signals such as ultraviolet-B irradiation, viral infection (herpes simplex virus), and translational inhibition increased the RNA level of PRINS. Gene-specific silencing of PRINS by RNA interference revealed that down-regulation of PRINS impairs cell viability after serum starvation but not under normal serum conditions. Our findings suggest that PRINS functions as a noncoding regulatory RNA, playing a protective role in cells exposed to stress. Furthermore, elevated PRINS expression in the epidermis may contribute to psoriasis susceptibility.

Gene expression profiles in psoriasis: analysis of impact of body site location and clinical severity

BACKGROUND

Psoriasis is characterized by symmetry of plaques and modulation of multiple genes within those plaques.

OBJECTIVES

We compared gene expression profiles of plaques of psoriasis at different anatomical sites for both symmetrical and asymmetrical disease to ascertain whether the same genes were expressed.

METHODS

Gene expression profiles were analysed in biopsies from lesional and uninvolved skin from two groups of patients with either predominantly symmetrical or truncal plaques of psoriasis vulgaris, and from normal skin of healthy volunteers. Genomic analyses were performed using cDNA array and kinetically monitored reverse transcriptase-initiated polymerase chain reaction (kRT-PCR) approaches. A cluster of genes upregulated in involved psoriasis skin as compared with normal skin was identified using each of these two technologies.

RESULTS

Clustering of patients based on their gene expression profile did not reveal any correlation with family history of psoriasis, age at onset or association of psoriasis with arthritis. There was no difference in gene expression profile between the type (symmetrical vs. truncal) or location (left vs. right side of body) of psoriatic plaques. Gene expression profiles of involved psoriatic skin analysed by kRT-PCR analysis did correlate with both global (Psoriasis Area and Severity Index) and local (erythema, desquamation and plaque elevation) clinical severity.

CONCLUSIONS

These results indicate that it may be feasible to analyse the molecular effects of pharmacological agents on psoriatic skin in 'minizone' protocols, that the obtained data can be correlated with clinical severity and that plaques of psoriasis in the same individual express the same genes.

Clinical considerations of efalizumab therapy in patients with psoriasis

Psoriasis is a chronic, incurable disease that often requires decades of therapy to maintain disease control. Efalizumab is a recombinant monoclonal IgG1 antibody approved for use in patients with chronic moderate-to-severe plaque psoriasis. To date, efalizumab has been evaluated extensively in more than 3500 patients, including in studies that have evaluated its efficacy and safety during extended use. Just as psoriasis fluctuates in severity, the response to treatment with efalizumab can vary among patients. On the basis of my personal experience managing patients in and out of clinical trials, most patients benefit from efalizumab. The possibility exists of intercurrent events during efalizumab therapy, such as the development of a transient localized papular eruption or mild arthralgia or, in a few patients, a generalized inflammatory flare or severe arthralgia. However, there are techniques to potentially manage these events in a manner that maximizes patient comfort and compliance. If dermatologists become comfortable recognizing the subset of patients who are overall excellent responders but develop a papular eruption or mild and manageable arthralgia, they will be able to readily incorporate this effective biologic into their daily practice. In this article, clinical trial data and case reports illustrate recommended patient management techniques and the substantial long-term benefits that psoriasis patients may realize with efalizumab therapy.

Psoriasis vulgaris: an interplay of T lymphocytes, dendritic cells, and inflammatory cytokines in pathogenesis

PURPOSE OF REVIEW

Discuss and update concepts and hypotheses for the pathogenesis of psoriasis based on new research reports (primarily from 2003 and early 2004).

RECENT FINDINGS

Increases in newly defined dendritic cell subsets, cytokines, and chemokines have been identified in psoriasis lesions and have modified views of T-cell-mediated pathogenesis. In addition, the psoriasis transcriptome has been defined by large-scale genomic expression studies, and these data suggest distinct molecular mechanisms of type 1 T-cell-mediated inflammation. Somewhat surprisingly, therapeutic clinical trials suggest that tumor necrosis factor is a major pathogenic cytokine in psoriasis, whereas translational studies point to roles of other innate pathways mediated by heat shock proteins, glycolipids, natural killer T cells, or dendritic cells in disease pathogenesis.

SUMMARY

An interactive network of inflammatory cytokines, chemokines, dendritic cells, and type 1 T cells or natural killer T cells potentially drives pathogenic inflammation in psoriasis vulgaris. Continued clinical studies with defined immune antagonists provide a critical means to dissect the contribution of different cell subsets and genomic pathways to the pathogenesis of psoriasis vulgaris.

Psoriasis and its treatment with infliximab-mediated tumor necrosis factor α blockade

The pathogenesis of psoriasis, a chronic immune-mediated inflammatory skin disease,involves increased concentrations and activity of several proinflammatory cytokines,including tumor necrosis factor alpha (TNF-alpha). Infliximab is a chimeric human-murine TNF-alpha antibody that selectively blocks the activity of TNF-alpha. In controlled clinical trials, infliximab treatment has produced rapid and sustained improvements in psoriasis lesions and psoriatic joint involvement, with a favorable short-term safety and tolerability profile. Treatment with infliximab may be associated with an increased risk of infection or infusion reaction: however, the side-effect profile of infliximab in patients with psoriasis remains to be fully characterized, and assessment of infliximab in this population is currently ongoing in phase 3 studies. Comprehensive evaluation in controlled trials may allow infliximab to take its place among the expanding group of biologic drugs for the treatment of moderate to severe psoriasis.

Serum TNF-alpha in psoriasis after treatment with propylthiouracil, an antithyroid thioureylene

Background

Tumor necrosis factor-α (TNF-α) and its receptors play important roles in the development and persistence of psoriatic plaques. The antithyroid thioureylenes, propylthiouracil and methimazole, are effective in the treatment of patients with psoriasis with a significant number of patients showing clearing or near clearing of their lesions after a several weeks of treatment.

Methods

The present study examined the effect of treatment with propylthiouracil, given in a dose of 100 mg every 8 hours for 3 months, on the serum levels of TNF-α in 9 patients with plaque psoriasis.

Results

Propylthiouracil therapy did not result in a significant decline in serum TNF-α concentrations.

Conclusions

The findings suggest that the therapeutic effect of propylthiouracil in psoriasis appears not to be related to any change in the concentration of TNF-α but occurs via an anti-proliferative mechanism as we have previously speculated.

Anti-thyroid thioureylenes in the treatment of psoriasis

Psoriasis is a common skin disorder associated with significant morbidity. Many agents are used in the medical management of this debilitating condition with the newer anti-cytokine agents being the most recent addition to the pharmacological armamentarium to battle the disorder. Cost concerns are very important with the newer "biologic" treatments costing in excess of 10,000 US dollars annually. The need for cheaper, orally administered agents is therefore imperative. This paper addresses the potential role of anti-thyroid thioureylenes, propylthiouracil and methimazole, in the treatment of psoriasis and reviews the possible mechanism of action of these drugs in this disorder. It is hypothesized that the beneficial effect of anti-thyroid thioureylenes in psoriasis is linked to their effect as anti-proliferative agents as reflected by significant decrease in markers of cellular proliferation such as proliferative cell nuclear antigen in biopsy specimens after treatment with these drugs. Propylthiouracil has been shown to bind to the hepatic T 3 receptor and it is possible that propylthiouracil (6-n-propyl-2-thiouracil) binding to the ligand-binding site normally occupied by T 3 impairs transcription by inactivating the effect of T 3 as well as by squelching retinoic X receptor heterodimer formation with other receptors of the steroid receptor superfamily such as the peroxisome proliferator-activated receptor, retinoic acid receptor and vitamin D receptors.

A putative RUNX1 binding site variant between SLC9A3R1 and NAT9 is associated with susceptibility to psoriasis

Psoriasis (OMIM 177900) is a chronic inflammatory skin disorder of unknown pathogenesis affecting approximately 2% of the Western population. It occurs more frequently in individuals with human immunodeficiency virus, and 20-30% of individuals with psoriasis have psoriatic arthritis. Psoriasis is associated with HLA class I alleles, and previous linkage analysis by our group identified a second psoriasis locus at 17q24-q25 (PSORS2; ref. 7). Linkage to this locus was confirmed with independent family sets. Additional loci have also been proposed to be associated with psoriasis. Here we describe two peaks of strong association with psoriasis on chromosome 17q25 separated by 6 Mb. Associated single-nucleotide polymorphisms (SNPs) in the proximal peak lie in or near SLC9A3R1 (also called EBP50 and NHERF1) and NAT9, a new member of the N-acetyltransferase family. SLC9A3R1 is a PDZ domain-containing phosphoprotein that associates with members of the ezrin-radixin-moesin family and is implicated in diverse aspects of epithelial membrane biology and immune synapse formation in T cells. The distal peak of association is in RAPTOR (p150 target of rapamycin (TOR)-scaffold protein containing WD-repeats). Expression of SLC9A3R1 is highest in the uppermost stratum Malpighi of psoriatic and normal skin and in inactive versus active T cells. A disease-associated SNP lying between SLC9A3R1 and NAT9 leads to loss of RUNX1 binding. This is the second example of loss of a RUNX1 binding site associated with susceptibility to an autoimmune disease. It also suggests defective regulation of SLC9A3R1 or NAT9 by RUNX1 as a susceptibility factor for psoriasis.