What have we learned about genetic susceptibility in psoriasis and psoriatic arthritis?

Differences between psoriatic arthritis and psoriasis in multi-omics

We aim to systemically review the genomics, transcriptomics, epigenetics, proteomics, metabonomics and microbiota of psoriatic arthritis and psoriasis, illustrating the differences of these two diseases, broadening our understanding of the pathogenesis of them and providing important clues for valuable biomarkers of earlier diagnosis and treatments. To our knowledge, this is the first study that combine all omics studies from genomics to microbiota and may serve as a reference for future studies to identify the key underlying pathways in psoriatic arthritis.

Associations of polysocial risk score, lifestyle and genetic factors with incident psoriasis: a larger-scale prospective cohort study

OBJECTIVES

The impact of polysocial risk score (PsRS), a composite measure of multiple social risk factors, on the development of psoriasis remains unclear. Moreover, the potential modifying effects of lifestyle and genetic susceptibility on the relationship between PsRS and psoriasis risk require further exploration.

STUDY DESIGN

This was a prospective cohort study conducted among UK Biobank.

METHODS

In this study, we analyzed 331,631 participants enrolled in the UK Biobank cohort. To derive the PsRS, we utilized a summative strategy, amalgamating six social determinants of health derived from three domains: socio-economic status, psychosocial factors, and neighborhood and living environment consistently linked to incident psoriasis. Cox proportional hazard models were used to assess the associations between PsRS and psoriasis incidence. Furthermore, we constructed a lifestyle score and a genetic risk score to explore the potential modifying effects of these factors on the relationship between PsRS and psoriasis risk.

RESULTS

Compared with individuals with a low PsRS (≤1), those with intermediate PsRS (2-4) and high PsRS (≥5) had 1.20 (95% confidence interval [CI], 1.06-1.36) and 1.53 (95% CI, 1.31-1.78) times higher risks of developing psoriasis, respectively. Our findings revealed an additive interaction between PsRS and genetic susceptibility. Moreover, it was found that individuals with high PsRS and unhealthier lifestyles had a 2.60 times higher risk of developing psoriasis than those with lower PsRS and healthier ones.

CONCLUSIONS

Our study results imply that an elevated PsRS is linked to a heightened risk of psoriasis, which is further influenced by genetic factors. Our results also indicate that greater social vulnerability and unhealthier lifestyle may synergistically contribute to the additional risk of psoriasis.

Efficacy of Guselkumab on Axial-Related Symptoms Through up to 2 Years in Adults with Active Psoriatic Arthritis in the Phase 3, Randomized, Placebo-Controlled DISCOVER-2 Study

INTRODUCTION

Guselkumab previously showed greater improvements versus placebo in axial symptoms in patients with psoriatic arthritis (PsA) (assessed by Bath Ankylosing Spondylitis Disease Activity Index [BASDAI] and Ankylosing Spondylitis Disease Activity Score [ASDAS]), in post hoc analyses of the phase 3, placebo-controlled, randomized DISCOVER-1 and DISCOVER-2 studies. We now evaluate durability of response in axial-related outcomes through 2 years of DISCOVER-2.

METHODS

DISCOVER-2 biologic-naive adults with active PsA (≥ 5 tender/ ≥ 5 swollen joints, C-reactive protein ≥ 0.6 mg/dl) were randomized to guselkumab 100 mg every 4 weeks (Q4W) or at week 0, week 4, then Q8W, or placebo → guselkumab Q4W at week 24. Among patients with imaging-confirmed sacroiliitis (investigator-identified), axial symptoms were assessed through 2 years utilizing BASDAI, BASDAI Question #2 (spinal pain), modified BASDAI (mBASDAI; excludes Question #3 [peripheral joint pain]), and ASDAS. Mean changes in scores and proportions of patients achieving ≥ 50% improvement in BASDAI (BASDAI 50) and ASDAS responses, including major improvement (decrease ≥ 2.0), were determined through week 100. Treatment failure rules (through week 24) and nonresponder imputation of missing data (post-week 24) were utilized. Mean BASDAI component scores were assessed through week 100 (observed data). Exploratory analyses evaluated efficacy by sex and HLA-B*27 status.

RESULTS

Among 246 patients with PsA and imaging-confirmed sacroiliitis, guselkumab-treated patients had greater mean improvements in BASDAI, mBASDAI, spinal pain, and ASDAS scores, lower mean BASDAI component scores, and greater response rates in achieving BASDAI 50 and ASDAS major improvement vs. placebo at week 24. Differences from placebo were observed for guselkumab-treated patients in selected endpoints regardless of sex or HLA-B*27 status. At week 100, mean improvements were ~ 3 points for all BASDAI scores and 1.6-1.7 for ASDAS; 49-54% achieved BASDAI 50 and 39% achieved ASDAS major improvement at week 100.

CONCLUSIONS

Guselkumab treatment provided durable and meaningful improvements in axial symptoms and disease activity in substantial proportions of patients with active PsA and imaging-confirmed sacroiliitis.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03158285.

Psoriasis and Psoriatic Arthritis Have a Major Impact on Quality of Life and Depressive Symptoms: A Cross-Sectional Study of 300 Patients

INTRODUCTION

Psoriasis (Pso) and psoriatic arthritis (PsA) can reduce the quality of life (QoL) and are known to be associated with depression. Within this study, we aimed to assess the burden of disease, functional capacity, quality of life, and depressive symptoms and identify factors predicting functional impairment and depression in patients with psoriatic disease.

METHODS

A cross-sectional survey was conducted in a cohort of 300 patients with psoriatic disease including 150 patients from a university hospital dermatology outpatient clinic and 150 patients from a university hospital rheumatology outpatient clinic. Questionnaire-based assessment of signs of arthritis (Psoriasis Epidemiology Screening Tool; PEST), functional status (Functional Questionnaire Hannover; FFbH), quality of life (World Health Organization Quality of Life Brief Version; WHOQOL-BREF), and depressive symptoms (Patient health questionnaire 9; PHQ-9) and retrospective medical chart analysis were performed.

RESULTS

Despite treatment, burden of disease was high. Joint pain was reported in multiple regions in patients with Pso (n = 111) and patients with PsA (n = 189), but with differences in frequency and distribution patterns of symptoms. Functional impairment in everyday life was independently associated with diagnosis of PsA (odds ratio [OR] 9.56, p = 0.005), depressive symptoms (OR 5.44, p < 0.001) and age (OR 1.04, p = 0.033). At least mild depressive symptoms were demonstrated in 54% and 69% of patients with Pso and PsA, respectively. In a logistic regression model, depressive symptoms were independently associated with functional impairment (OR 4.50, p = 0.003), axial complaints (OR 2.80, p = 0.030), diagnosis of psoriatic arthritis (OR 2.69, p = 0.046), and number of joint regions with complaints (OR 1.10, p = 0.032).

CONCLUSION

Functional impairment, QoL, and depressive symptoms are mutually interdependent. Early diagnosis of PsA and initiation of anti-inflammatory therapy are essential to avoid long-term damage, disability, and mental health complications. However, despite therapy many patients with PsA, and especially female patients, report a substantial residual disease burden due to their psoriatic disease which will need to be addressed by a more patient-centered approach.

Genetic and Molecular Distinctions Between Axial Psoriatic Arthritis and Radiographic Axial Spondyloarthritis: Post Hoc Analyses from Four Phase 3 Clinical Trials

INTRODUCTION

Emerging evidence suggests psoriatic arthritis (PsA) with axial involvement (axPsA) and radiographic axial spondyloarthritis (r-axSpA) may possibly represent distinct disorders, with some differing clinical manifestations, genetic associations, and radiographic findings. Moreover, axPsA and r-axSpA may respond differently to therapies: guselkumab (interleukin [IL]-23p19 subunit inhibitor [i]) and ustekinumab (IL-12/23p40i) demonstrated improvements in axial symptoms in patients with PsA; however, neither risankizumab (IL-23p19i) nor ustekinumab demonstrated efficacy versus placebo in patients with r-axSpA. Current analyses aim to further understand potential molecular distinctions between axPsA and r-axSpA and examine the pharmacodynamic effects of guselkumab in patients with axPsA and those with PsA without axial involvement (non-axPsA).

METHODS

Post hoc analyses utilized biomarker data from blood and serum samples collected from a subset of participants in phase 3 studies of ustekinumab in r-axSpA and guselkumab in PsA (DISCOVER-1 and DISCOVER-2). Participants with axPsA were identified by investigator-verified sacroiliitis (imaging-confirmed) and axial symptoms. HLA mapping, serum cytokine analysis, and whole-blood RNA sequencing were conducted.

RESULTS

Relative to r-axSpA, patients with axPsA had a lower prevalence of HLA-B27, HLA-C01, and HLA-C02 alleles and a higher prevalence of HLA-B13, HLA-B38, HLA-B57, HLA-C06, and HLA-C12 alleles. Compared with r-axSpA, patients with axPsA had elevated baseline levels of serum IL-17A and IL-17F cytokines, enrichment of IL-17 and IL-10 pathway-associated genes, and neutrophil gene markers. Across axPsA and non-axPsA cohorts, reductions in cytokine levels and normalization of pathway-associated gene expression with guselkumab treatment were comparable.

CONCLUSION

The differences in HLA genetic associations, serum cytokines, and enrichment scores support the concept that axPsA and r-axSpA may be distinct disorders. The comparable pharmacodynamic effects of guselkumab on cytokine levels and pathway-associated genes observed in patients with axPsA and non-axPsA are consistent with demonstrated clinical improvements across PsA cohorts. These findings contribute to the understanding of potential genetic and molecular distinctions between axPsA and r-axSpA.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers, NCT03162796, NCT0315828, NCT02437162, and NCT02438787.

Managing Psoriatic Arthritis Patients Presenting with Axial Symptoms

Axial symptoms (i.e., back pain) are common in the general population. At the same time 25-70% of patients with psoriatic arthritis (PsA) exhibit signs of inflammatory axial involvement (axial PsA). The presence of unexplained chronic (duration ≥ 3 months) back pain in a patient with psoriasis or PsA should trigger evaluation of the presence of axial involvement. Evaluation of axial involvement normally involves imaging of the axial skeleton (sacroiliac joints and/or spine) in addition to clinical and laboratory evaluation. Symptomatic patients with confirmed axial PsA are treated with a combination of non-pharmacologic and pharmacologic methods including the use of non-steroidal anti-inflammatory drugs, tumour necrosis factor, interleukin 17, and Janus kinase inhibitors. Interleukin 23 blockade might also be effective in the axial domain of PsA; a dedicated clinical study is ongoing at present. Safety considerations, patient preference, as well as the presence of other disease manifestations (especially of extra-musculoskeletal manifestations-clinically relevant psoriasis, acute anterior uveitis, inflammatory bowel disease), define the choice of a specific drug or drug class.

Phenotypic heterogeneity in psoriatic arthritis: towards tissue pathology-based therapy

Psoriatic arthritis (PsA) is a heterogeneous disease involving multiple potential tissue domains. Most outcome measures used so far in randomized clinical trials do not sufficiently reflect this domain heterogeneity. The concept that pathogenetic mechanisms might vary across tissues within a single disease, underpinning such phenotype diversity, could explain tissue-distinct levels of response to different therapies. In this Review, we discuss the tissue, cellular and molecular mechanisms that drive clinical heterogeneity in PsA phenotypes, and detail existing tissue-based research, including data generated using sophisticated interrogative technologies with single-cell precision. Finally, we discuss how these elements support the need for tissue-based therapy in PsA in the context of existing and new therapeutic modes of action, and the implications for future PsA trial outcomes and design.

A Promising Approach of Dermal Targeting of Antipsoriatic Drugs via Engineered Nanocarriers Drug Delivery Systems for Tackling Psoriasis

Psoriasis is a complex autoimmune skin condition with a significant genetic component. It causes skin inflammation and is characterized by flaky, silvery reddish spots that can worsen with age. This condition results from an impaired immunological response of T-cells and affects 2-5% of the global population. The severity of the illness determines the choice of treatment. Topical treatments are commonly used to treat psoriasis, but they can have several adverse effects. Biological therapy is another option for treating specific types of psoriasis. Recently, new nanoformulations have revolutionized psoriasis treatment. Various nanocarriers, such as liposomes, nanostructured lipid nanoparticles, niosomes, and nanoemulsions, have been developed and improved for drug delivery. The use of nanocarriers enhances patient compliance, precise drug delivery, and drug safety. This review aims to suggest new nanocarrier-based drug delivery systems for treating psoriasis. It discusses the importance of nanocarriers and compares them to traditional treatments. Anti-psoriatic drugs have also been investigated for cutaneous delivery using nanocarriers. The review also covers various factors that influence dermal targeting. By highlighting several relevant aspects of psoriasis treatment, the review emphasizes the current potential of nanotechnology. Using nanocarriers as a drug delivery technique may be a promising alternative treatment for psoriasis.

Axial involvement in psoriatic arthritis

Among the variety of clinical manifestations of psoriatic arthritis (PsA) – including peripheral arthritis, dactylitis, enthesitis, and axial disease – spondylitis is the least studied. There is no generally accepted definition of axial PsA (axPsA), nor is there any common terminology or diagnostic criteria for it. In the rheumatology community, there is also no consensus regarding radiological and MRI assessment of axial involvement in PsA patients, while disease activity indexes and the therapeutic tactics are borrowed from those used in treating axial spondyloarthritis (axSpA) and ankylosing spondylitis (AS). However, despite a range of similarities in immunopathogenetic mechanisms of axPsA and axSpA, there are also certain differences that may affect the treatment response in these patients. The aim of this review is the analysis of data on axial disease in PsA. The article discusses the genetic features, clinical presentations, imaging techniques, differential diagnostics and treatment options of axPsA.

Isolated axial disease in psoriatic arthritis and ankylosing spondylitis with psoriasis

OBJECTIVES

To compare isolated axial psoriatic arthritis (PsA), axial PsA with peripheral involvement and isolated axial ankylosing spondylitis (AS) with psoriasis. To evaluate predictors for developing peripheral disease from isolated axial PsA over time.

METHODS

Two PsA and AS cohorts identified patients with PsA with axial disease and isolated axial patients with AS with psoriasis. Logistic regression compared isolated axial PsA to axial PsA with peripheral involvement and isolated axial AS with psoriasis. Cox proportional hazards model evaluated predictors for developing peripheral disease from isolated axial PsA.

RESULTS

Of 1576 patients with PsA, 2.03% had isolated axial disease and 29.38% had axial and peripheral disease. human leucocyte antigen HLA-B*27 positivity (OR 25.00, 95% CI 3.03 to 206.11) and lower Health Assessment Questionnaire scores (OR 0.004, 95% CI 0.00 to 0.28) were associated with isolated axial disease. HLA-B*27 also predicted peripheral disease development over time (HR 7.54, 95% CI 1.79 to 31.77). Of 1688 patients with AS, 4.86% had isolated axial disease with psoriasis. Isolated axial patients with PsA were older at diagnosis (OR 1.06, 95% CI 1.01 to 1.13), more likely to have nail lesions (OR 12.37, 95% CI 2.22 to 69.07) and less likely to have inflammatory back pain (OR 0.12, 95% CI 0.02 to 0.61) compared with patients with isolated axial AS with psoriasis.

CONCLUSIONS

Isolated axial PsA and AS with psoriasis are uncommon. HLA-B*27 positivity is associated with isolated axial PsA and may identify those who develop peripheral disease over time. Isolated axial PsA is associated with better functional status. Isolated axial PsA appears clinically distinct from isolated axial AS with psoriasis.

Etiopathogenesis of Psoriasis from Genetic Perspective: An updated Review

Psoriasis is an organ-specific autoimmune disease characterized by the aberrant proliferation and differentiation of keratinocytes, leading to skin lesions. Abnormal immune responses mediated by T cells and dendritic cells and increased production of inflammatory cytokines have been suggested as underlying mechanisms in the pathogenesis of psoriasis. Emerging evidence suggests that there is a heritable basis for psoriatic disorders. Moreover, numerous gene variations have been associated with the disease risk, particularly those in innate and adaptive immune responses and antigen presentation pathways. Herein, this article discusses the genetic implications of psoriatic diseases' etiopathogenesis to develop novel investigative and management options.

Incidence and prevalence of psoriatic arthritis in patients with psoriasis stratified by psoriasis disease severity: Retrospective analysis of an electronic health records database in the United States

BACKGROUND

Among patients in the United States with psoriasis (PsO), limited data exist on the incidence and prevalence of psoriatic arthritis (PsA) based on disease severity.

OBJECTIVE

To assess the incidence, prevalence, and predictors of PsA among patients with PsO stratified by PsO severity using treatment type.

METHODS

Incidence of PsA per 100 PsO patient-years (PY) and prevalence were assessed using the Optum electronic health records database. Incidence was assessed from PsO diagnosis and 1 year after PsO diagnosis overall and stratified by mutually exclusive treatment classes as a severity surrogate.

RESULTS

The overall incidence of PsA was 2.9 (95% CI, 2.9-3.0) events per 100 PY. The incidence (95% CI) by severity surrogate was 2.1 (2.1-2.1), 9.9 (9.5-10.4), and 17.6 (16.9-18.3) events per 100 PY for patients with mild, moderate, and severe PsO as determined by receiving nonsystemics, nonbiologic systemic therapy, and biologics, respectively. When excluding patients diagnosed with PsA 1 year after PsO diagnosis, overall incidence was lower (1.7 [95% CI, 1.6-1.7] events per 100 PY), with similar trends for treatment-severity surrogates.

LIMITATIONS

Results may not be generalizable to a wider population.

CONCLUSION

The risk of developing PsA increased with disease severity and was highest in patients with the most severe PsO.

Characterising axial psoriatic arthritis: correlation between whole spine MRI abnormalities and clinical, laboratory and radiographic findings

OBJECTIVE

To describe the prevalence of inflammatory and structural lesions using whole spine MRI in patients with psoriatic disease, and to assess their correlation with clinical features and with axial spondyloarthritis (axSpA) classification criteria.

METHODS

This retrospective analysis included patients with whole spine and sacroiliac joints (SIJ) MRI, selected from 2 populations: (1) active psoriatic arthritis (PsA), irrespective of axial symptoms; (2) psoriasis with confirmed or suspected PsA and axSpA symptoms. MRI spondylitis and/or sacroiliitis (MRI-SpA) was defined according to Assessment of Spondyloarthritis International Society (ASAS) consensus and by radiologist impression. Agreement between MRI-SpA and different inflammatory back pain (IBP) definitions (Berlin/ASAS/rheumatologist criteria) and the axSpA classification criteria were calculated considering MRI as gold standard. Logistic regression determined MRI-SpA-associated factors.

RESULTS

93 patients were analysed (69.9% PsA; 30.1% psoriasis). Back pain was present in 81.7%, defined as IBP in 36.6%-57%. MRI-SpA was found in 9.7% of patients by ASAS definition and in 12.9% by radiologist impression, of which 25% had isolated spondylitis.Low agreement was found between the three IBP definitions and MRI-SpA. Rheumatologist criteria was the most sensitive (50%-55.6%) while ASAS and Berlin criteria were the most specific (61.9%-63%). axSpA criteria had poor sensitivity for MRI-SpA (22.2%-25%). Late onset of back pain or asymptomatic patients accounted for most cases with MRI-SpA not meeting axSpA or IBP criteria. Male sex was associated with MRI-SpA (OR 6.91; 95% CI 1.42 to 33.59) in multivariable regression analysis.

CONCLUSION

Prevalence of MRI-defined axSpA was low and showed poor agreement with IBP and axSpA criteria.

Efficacy of guselkumab on axial involvement in patients with active psoriatic arthritis and sacroiliitis: a post-hoc analysis of the phase 3 DISCOVER-1 and DISCOVER-2 studies

BACKGROUND

Guselkumab was efficacious in reducing signs and symptoms of psoriatic arthritis in the phase 3 DISCOVER-1 and DISCOVER-2 studies. We aimed to evaluate the efficacy of guselkumab in post-hoc analyses of patients with psoriatic arthritis with imaging-confirmed sacroiliitis consistent with axial involvement.

METHODS

In DISCOVER-1, 381 patients with active psoriatic arthritis (defined as ≥3 swollen joints, ≥3 tender joints, and C-reactive protein [CRP] ≥0·3 mg/dL) and in DISCOVER-2, 739 patients with active psoriatic arthritis (defined as ≥5 swollen joints, ≥5 tender joints, and CRP ≥0·6 mg/dL) were randomly allocated to receive guselkumab 100 mg every 4 weeks, guselkumab 100 mg every 8 weeks (week 0, week 4, then every 8 weeks), or placebo. These pooled, post-hoc analyses included patients with axial disease documented by previous imaging or pelvic radiography at screening consistent with sacroiliitis (confirmed by investigator). Efficacy assessments included least squares mean changes, with 95% CIs, in Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score, modified BASDAI (mBASDAI; excluding peripheral joint pain), spinal pain, and Ankylosing Spondylitis Disease Activity Score (ASDAS), and proportions of patients achieving at least a 50% improvement in BASDAI score (BASDAI50) and achieving ASDAS responses of inactive disease (score <1·3), major improvement (change of ≥2·0), and clinically important improvement (change of ≥1·1).

FINDINGS

Of the 1120 patients in the two DISCOVER studies, 312 (28%) were included in this analysis, of whom 118 were in the placebo group, 103 were in the guselkumab every 4 weeks group, and 91 were in the guselkumab every 8 weeks group. 191 (61%) were male, and 121 (39%) were female, and the mean age was 45·1 (SD 11·2). HLA-B27 status was assessed in 190 patients; 57 (30%) were HLA-B27-positive and 133 (70%) were HLA-B27-negative. At week 24, least squares mean changes from baseline in BASDAI were -2·7 (95% CI -3·2 to -2·2) in both guselkumab groups versus -1·3 (-1·8 to -0·9) in the placebo group; similar results were observed for mBASDAI and spinal pain. Least squares mean changes in ASDAS scores at week 24 were -1·4 (95% CI -1·7 to -1·2) in both guselkumab groups and -0·7 (-0·9 to -0·5) for placebo. At week 24, 36 (38%) patients in the guselkumab every 4 weeks group and 34 (40%) of those in the guselkumab every 8 weeks group achieved BASDAI50 versus 21 (19%) of placebo patients; greater proportions of guselkumab-treated patients achieved ASDAS responses versus placebo. Across outcomes, separation from placebo was observed at week 8. Improvements with guselkumab were seen at week 24 independent of HLA-B27 status. These improvements were maintained at week 52 in the guselkumab groups.

INTERPRETATION

Patients with active psoriatic arthritis and imaging-confirmed sacroiliitis who were treated with guselkumab every 4 weeks or every 8 weeks had greater mean improvements in BASDAI and ASDAS (as early as week 8) than did placebo-treated participants, with sustained improvements at week 52.

FUNDING

Janssen Research & Development LLC.

Unraveling the complexities of psoriatic arthritis by the use of -Omics and their relevance for clinical care

-Omic technologies represent a novel approach to unravel ill-defined aspects of psoriatic arthritis (PsA). Large-scale information can be acquired from analysis of affected tissues in PsA via high-throughput studies in the domains of genomics, transcriptomics, epigenetics, proteomics and metabolomics. This is a critical overview of the current knowledge of -omics in PsA, with emphasis on the pathophysiological insights of diagnostic and therapeutic relevance, the advent of novel biomarkers and their potential use for precision medicine in PsA.

MicroRNAs in Axial Spondylarthritis: an Overview of the Recent Progresses in the Field with a Focus on Ankylosing Spondylitis and Psoriatic Arthritis

Purpose of Review

To highlight the recent discoveries and lines of evidence on the role of microRNAs in ankylosing spondylitis (AS) and psoriatic arthritis (PsA), focusing on their expression profiling and mechanisms of action.

Recent Findings

AS and PsA are chronic inflammatory musculoskeletal diseases with axial manifestations and represent an excellent model for studying microRNAs contribution to the disease pathogenesis, particularly through immunomodulation, inflammation, and bone remodelling, or their value as candidate diagnostic and prognostic biomarkers.

Summary

MicroRNAs are single-stranded nucleotides able to regulate gene expression. They are a key component of the epigenetic machinery, involved in physiological and pathological processes. The contribution of microRNAs in AS and PsA (such as miR-29a in regulating bone metabolism) is highlighted by several works in the field but their utility as possible markers must be still confirmed, particularly in larger patients’ cohorts.

A clinical perspective on risk factors and signs of subclinical and early psoriatic arthritis among patients with psoriasis

Psoriasis is a chronic, immune-mediated disease that includes a broad spectrum of systemic manifestations, complications, and comorbidities. Approximately 20%-30% of patients with psoriasis eventually develop psoriatic arthritis, and up to half of those without psoriatic arthritis experience subclinical musculoskeletal abnormalities. Recognition of early musculoskeletal inflammatory signs in patients with psoriasis is important to understand the extent and severity of this systemic disease, assess the risk of structural joint damage, and ensure timely and effective treatment of the complete spectrum of psoriatic disease. Delayed or ineffective treatment can lead to decreased quality of life, irreversible musculoskeletal damage, and loss of function. In this review, we highlight features of subclinical or early psoriatic arthritis among patients with psoriasis of which dermatologists should be aware. Recent knowledge of features of preclinical psoriatic arthritis in patients with psoriasis is presented. We briefly discuss important risk factors, clinical features, and other characteristics of patients likely to progress from psoriasis to psoriatic arthritis that should be known by dermatologists. Screening tools commonly used in the dermatology clinic to detect psoriatic arthritis are also critically reviewed. Finally, we provide expert commentary for dermatologists concerning the treatment of patients with psoriasis and subclinical signs of early psoriatic arthritis.

Axial involvement in psoriatic arthritis: An update for rheumatologists

Psoriatic arthritis (PsA) is a heterogenous, chronic, inflammatory musculoskeletal disease that can lead to peripheral and axial damage and loss of function. Axial involvement occurs in 25% to 70% of patients with PsA, varying greatly depending on its definition, with the key manifestations being sacroiliitis and/or spondylitis. However, there are no agreed-upon classification or diagnostic criteria for axial involvement in PsA and no consensus on treatment paradigms, which complicates management of PsA. There have only been a few studies assessing biologics in patients with PsA with axial involvement, and most treatment plans are based on evidence from patients with axial spondyloarthritis. Rheumatologists therefore face many challenges in the management of axial PsA, including diagnosis, differential diagnosis, and choice of appropriate treatment. In this review, we summarize the clinical presentation, imaging characteristics, differential diagnoses, treatment options, and prognosis of axial PsA, with the aim of increasing rheumatologists' knowledge of this phenotype of PsA and thereby aiding its optimal management.

The causal effect of interleukin-17 on the risk of psoriatic arthritis: a Mendelian randomization study

OBJECTIVE

To determine causal associations between genetically predicted TNF-α, IL-12p70 and IL-17 levels and risk of PsA.

METHODS

The publicly available summary-level findings from genome-wide association studies (GWAS) was used to identify loci influencing normal physiological concentrations of TNF-α, IL-12p70 and IL-17 (n = 8293) among healthy individuals as exposure and a GWAS for PsA from the UK Biobank (PsA = 900, control = 462 033) as the outcome. A two-sample Mendelian randomization (MR) analysis was performed using the inverse-variance weighted (IVW), weighted median and MR-Egger regression methods. Sensitivity analysis and MR-Egger regression analysis were performed to evaluate the heterogeneity and pleiotropic effects of each variant.

RESULTS

Single-nucleotide polymorphisms (SNPs) at genome-wide significance from GWASs on TNF-α, IL-12p70 and IL-17 were identified as the instrumental variables. The IVW method indicated a causal association between increased IL-17 level and risk of PsA (β = -0.00186 per allele, s.e. = 0.00043, P = 0.002). Results were consistent in the weighted median method (β = -0.00145 per allele, s.e. = 0.00059, P = 0.014) although the MR-Egger method suggested a non-significant association (β = -0.00133 per allele, s.e. = 0.00087; P = 0.087). Single SNP MR results revealed that the C allele of rs117556572 was robustly associated with risk of PsA (β = 0.00210, s.e. = 0.00069, P = 0.002). However, no evidence for a causal effect was observed between TNF-α, IL-12p70, decreased IL-17 levels and risk of PsA.

CONCLUSION

Our findings provide preliminary evidence that genetic variants predisposing to higher physiological IL-17 level are associated with decreased risk of PsA.

Prevalence of Nonradiographic Sacroiliitis in Patients With Psoriatic Arthritis: A Real-life Observational Study

OBJECTIVE

To establish the prevalence of nonradiographic sacroiliitis within a real-life sample of patients with psoriatic arthritis (PsA), using pelvic radiographs and magnetic resonance imaging (MRI) of sacroiliac joints (SIJs).

METHODS

This cross-sectional study included 107 consecutive adults with PsA (Classification Criteria for Psoriatic Arthritis criteria). Participants completed clinical and laboratory evaluation, pelvic radiographs scored for radiographic sacroiliitis according to the modified New York (mNY) criteria, and noncontrast MRI of SIJs, scored by the Berlin score and categorized into active sacroiliitis using the 2016 Assessment of Spondyloarthritis international Society (ASAS) criteria and the presence of structural sacroiliitis.

RESULTS

Radiographic sacroiliitis/mNY criteria were detected in 28.7% (n = 29), confirmed by MRI-detected structural lesions in 72.4% (n = 21). Active sacroiliitis was detected by MRI in 26% (n = 28) of patients, with 11% (n = 11) qualifying for nonradiographic sacroiliitis. Patients with radiographic and nonradiographic sacroiliitis had similar clinical characteristics, except for a longer duration of psoriasis (PsO) and PsA in the radiographic subgroup (PsO: 23.8 ± 12.5 vs 14.1 ± 11.7 yrs, P = 0.03; PsA: 12.3 ± 9.8 vs 4.7 ± 4.5 yrs, P = 0.02, respectively). Inflammatory back pain (IBP) was reported in 46.4% (n = 13) with active sacroiliitis and 27% (n = 3) with nonradiographic sacroiliitis. The sensitivity of IBP for detection of nonradiographic sacroiliitis was low (27%) and moderate for radiographic sacroiliitis (52%), whereas specificity ranged from 72% to 79% for radiographic and nonradiographic sacroiliitis, respectively.

CONCLUSION

The prevalence of active sacroiliitis among a real-life population of patients with PsA was 26%. However, the prevalence of nonradiographic sacroiliitis was low (11%) compared to the radiographic sacroiliitis (28.7%) seen in patients with longer disease duration. IBP was not a sensitive indicator for the presence of early-stage sacroiliitis that was commonly asymptomatic.

The Influence of Vitamin D Receptor Gene Polymorphisms in Spondyloarthritis

Spondyloarthritis (SpA) is an inflammatory rheumatic disease related to low bone mineral density. Because vitamin D plays an important role in bone metabolism and immune system modulation, the aim of this study was to evaluate the influence of polymorphisms in vitamin D receptor genes (VDR) in the development of SpA. In this case-control study, a total of 244 patients with SpA and 197 individuals with no SpA were included. Among the patients, 174 had ankylosing spondylitis (AS) and 66 had psoriatic arthritis (PsA). Genotyping of FokI (rs2228570 C > T), BsmI (rs1544410 C > T), ApaI (rs7975232 A > C), and TaqI (rs731236 T > C) was performed using PCR-RFLP, while genotyping of HLA-B∗27 was performed using PCR-SSP. Serum levels for hydroxy (OH) vitamin D and the clinical activity index of the disease (BASDAI) were also evaluated. SNPStats and OpenEpi software were used for statistical analysis. The ApaI a allele and ApaI a/a genotype were less frequent in PsA compared with controls. The ApaI a/a genotype was associated with a protecting factor for PsA in females, and ApaI A/a was associated with a protecting factor for the disease in HLA-B∗27 positive patients. Notwithstanding, the ApaI a/a genotype was a risk factor for SpA and AS in males. The FokI f/f genotype was associated with a better clinical activity in PsA. When considering the covariates, vitamin D sufficiency, and gender, the FokI F/F genotype was associated with a risk factor in males with SpA and AS compared with females with this same genotype. In conclusion, the ApaI rs7975232 polymorphism was associated with PsA, and the FokI rs2228570 polymorphism was associated with better clinical PsA activity. ApaI and FokI were associated with SpA and AS when considering gender and vitamin D sufficiency.

IL-23/IL-17 Axis in Inflammatory Rheumatic Diseases

In inflammatory rheumatic disorders, the immune system attacks and damages the connective tissues and invariably internal organs. During the past decade, remarkable advances having been made towards our understanding on the cellular and molecular mechanisms involved in rheumatic diseases. The discovery of IL-23/IL-17 axis and the delineation of its important role in the inflammation led to the introduction of many needed new therapeutic tools. We will present an overview of the rationale for targeting therapeutically the IL-23/IL-17 axis in rheumatic diseases and the clinical benefit which has been realized so far. Finally, we will discuss the complex interrelationship between IL-23 and IL-17 and the possible uncoupling in certain disease settings.

Axial disease in psoriatic arthritis and ankylosing spondylitis: a critical comparison

Ankylosing spondylitis (AS) was first identified in the late 17th century. 250 years later, inflammatory spine disease was recognized to be one of the patterns of psoriatic arthritis (PsA). Isolated spondylitis is rare among patients with PsA, occurring in less than 5% of patients; however, many patients with PsA have axial disease that is concurrent with peripheral arthritis. At the other end of the spondyloarthritis spectrum, psoriasis is observed in 10% of patients with AS. Although axial involvement in PsA can be indistinguishable from axial disease in AS, it can also differ in several respects, raising the question of whether axial PsA and AS (with or without psoriasis) are different clinical presentations of the same disease, or whether they are separate diseases that have overlapping features. In this Review, the clinical presentation, metrology, radiographic characteristics, genetic factors, treatment options and axial prognosis of the two diseases are addressed. The aim of this Review is to capture all available comparisons made to date, to highlight the similarities and differences between AS and axial PsA and to propose a research agenda.

Psoriatic arthritis for dermatologists

Psoriatic arthritis (PsA) affects up to one-third of patients with psoriasis. It is the major comorbidity of psoriasis because of the likelihood that loss of function and permanent disability will develop if initiation of treatment is delayed. Dermatologists are uniquely positioned to recognize early signs of PsA and be the first-line healthcare practitioners to detect PsA in patients with psoriasis. PsA can affect six clinical domains: peripheral arthritis, dactylitis, enthesitis, psoriasis, psoriatic nail disease, and axial disease. However, not every patient will have involvement of all domains and the domains affected can change over time. Complicating the diagnosis is the condition's similarity with other arthritic diseases and potential heterogeneity. In this article, we provide practical guidance for dermatologists for detecting PsA in patients with psoriasis. We also review the available treatment options by each clinical domain of PsA and give advice on how to interpret the results of PsA clinical trials. Through early recognition of PsA in patients with psoriasis and initiation of proper treatment, dermatologists can help to prevent PsA disease progression, irreversible joint damage, and resultant permanent disability, and improve quality of life.

Utilization of the validated Psoriasis Epidemiology Screening Tool to identify signs and symptoms of psoriatic arthritis among those with psoriasis: a cross-sectional analysis from the US-based Corrona Psoriasis Registry

Background

Despite increasing awareness of the disease, rates of undiagnosed psoriatic arthritis (PsA) are high in patients with psoriasis (PsO). The validated Psoriasis Epidemiology Screening Tool (PEST) is a five‐item questionnaire developed to help identify PsA at an early stage.

Objectives

To assess the risk of possible undiagnosed PsA among patients with PsO and characterize patients based on PEST scores.

Methods

This study included all patients enrolled in the Corrona PsO Registry with data on all five PEST questions. Demographics, clinical characteristics and patient‐reported outcomes were compared in Corrona PsO Registry patients with PEST scores ≥3 and <3 using t‐tests for continuous variables and chi‐squared tests for categorical variables; scores ≥3 may indicate PsA.

Results

Of 1516 patients with PsO, 904 did not have dermatologist‐reported PsA; 112 of these 904 patients (12.4%) scored ≥3 and were significantly older, female, less likely to be working, and had higher BMI than patients with scores <3. They also had significantly longer PsO duration, were more likely to have nail PsO and had worse health status, pain, fatigue, Dermatology Life Quality Index and activity impairment.

Conclusions

Improved PsA screening is needed in patients with PsO because the validated PEST identified over one‐tenth of registry patients who were not noted to have PsA as having scores ≥3, who could have had undiagnosed PsA. Appropriate, earlier care is important because these patients were more likely to have nail PsO, worse health‐related quality of life and worse activity impairment.

Epigenome-wide analysis of sperm cells identifies IL22 as a possible germ line risk locus for psoriatic arthritis

Psoriasis and its associated inflammatory arthritis, psoriatic arthritis (PsA), have a clear heritable component, but a large proportion of the heritable risk remains unexplained by gene sequence variation. This study aimed to determine if epigenetic factors contribute to the missing heritability in psoriatic disease. DNA methylation profiling was performed on sperm cells from 23 probands with psoriasis without PsA (PsC), 13 PsA probands, and 18 unaffected controls. Differentially methylated CpGs and regions (DMRs) were identified and validated by pyrosequencing. Underlying AluY and copy number variation (CNV) in the HCG26 and IL22 genes, respectively, were assessed by genotyping. Array, subject's age, age of psoriasis onset, psoriasis severity, and medication usage were found to influence methylation at many genes and were included as covariates in the analysis. Between PsC probands vs. controls, 169 DMRs were found; 754 DMRs were found between PsA probands vs. controls, and 86 between PsA and PsC probands (adjusted p<0.05). Differences in methylation across DMRs were generally subtle (<10%) but correlated well with pyrosequencing. Biological inference prioritized notable DMRs associated with skin disease (SIGLEC14, JAM3, PCOLCE, RXRB), skin and/or joint disease (MBP, OSBPL5, SNORD115, HCG26), and joint disease (IL22, ELF5, PPP2R2D, PTPRN2, HCG26). Hypermethylation of the DMR within the first exon of arthritis-associated IL22 showed significant correlation (rho = 0.34, 95% CI 0.06-0.57, p = 0.01) between paired sperm and blood samples, independent of a CNV within the same region. Further studies are needed to rule out underlying genetic causes and determine if these represent heritable, constitutional epimutations, or are the result of exposure of germ cells to endogenous or exogenous environmental factors.

Familial Aggregation of Psoriasis and Co-Aggregation of Autoimmune Diseases in Affected Families

Psoriasis is considered to result from the interaction of genetic factors and environmental exposure. The evidence for familial aggregation in psoriasis has been reported but population-based studies related to the magnitude of genetic contribution to psoriasis are rare. This study aimed to evaluate the relative risks of psoriasis in individuals with affected relatives and to calculate the proportion of genetic, shared, and non-shared environmental factors contributing to psoriasis. The study cohort included 69,828 patients diagnosed with psoriasis enrolled in National health Insurance in 2010. The adjusted relative risks (RR) for individuals with an affected first-degree relative and affected second-degree relative were 5.50 (95% CI (Confidence Interval), 5.19–5.82) and 2.54 (95% CI, 2.08–3.12) respectively. For those who have affected first-degree relatives, their RR was 1.45 (95% CI, 1.17–1.79) for Sjogren’s syndrome and 1.94 (95% CI, 1.15–3.27) for systemic sclerosis. This nationwide study ascertains that family history of psoriasis is a risk factor for psoriasis. Individuals with relatives affected by psoriasis have higher risks of developing some autoimmune diseases.

Role of the IL-23/IL-17 Axis in Psoriasis and Psoriatic Arthritis: The Clinical Importance of Its Divergence in Skin and Joints

Psoriasis is a chronic systemic inflammatory disease causing erythematosus and scaly skin plaques; up to 30% of patients with psoriasis develop Psoriatic Arthritis (PsA), which is characterised by inflammation and progressive damage of the peripheral joints and/or the spine and/or the entheses. The pathogenic mechanisms driving the skin disorder in psoriasis and the joint disease in PsA are sustained by the activation of inflammatory pathways that can be overlapping, but also, at least partially, distinct. Cytokines members of the IL-23/IL-17 family, critical in the development of autoimmunity, are abundantly expressed within the cutaneous lesions but also seem to be involved in chronic inflammation and damage of the synovium though, as it will be here discussed, not in all patients. In this review, we will focus on the state of the art of the molecular features of psoriatic skin and joints, focusing on the specific role of the IL-23/IL-17 pathway in each of these anatomical districts. We will then offer an overview of the approved and in-development biologics targeting this axis, emphasising how the availability of the “target” in the diseased tissues could provide a plausible explanation for the heterogeneous clinical efficacy of these drugs, thus opening future perspective of personalised therapies.

Variable selection and prediction in biased samples with censored outcomes

With the increasing availability of large prospective disease registries, scientists studying the course of chronic conditions often have access to multiple data sources, with each source generated based on its own entry conditions. The different entry conditions of the various registries may be explicitly based on the response process of interest, in which case the statistical analysis must recognize the unique truncation schemes. Moreover, intermittent assessment of individuals in the registries can lead to interval-censored times of interest. We consider the problem of selecting important prognostic biomarkers from a large set of candidates when the event times of interest are truncated and right- or interval-censored. Methods for penalized regression are adapted to handle truncation via a Turnbull-type complete data likelihood. An expectation-maximization algorithm is described which is empirically shown to perform well. Inverse probability weights are used to adjust for the selection bias when assessing predictive accuracy based on individuals whose event status is known at a time of interest. Application to the motivating study of the development of psoriatic arthritis in patients with psoriasis in both the psoriasis cohort and the psoriatic arthritis cohort illustrates the procedure.

Autoimmune aspects of psoriasis: Heritability and autoantigens

Chronic immune-mediated disorders (IMDs) constitute a major health burden. Understanding IMD pathogenesis is facing two major constraints: Missing heritability explaining familial clustering, and missing autoantigens. Pinpointing IMD risk genes and autoimmune targets, however, is of fundamental importance for developing novel causal therapies. The strongest association of all IMDs is seen with human leukocyte antigen (HLA) alleles. Using psoriasis as an IMD model this article reviews the pathogenic role HLA molecules may have within the polygenic predisposition of IMDs. It concludes that disease-associated HLA alleles account for both missing heritability and autoimmune mechanisms by facilitating tissue-specific autoimmune responses through autoantigen presentation.

Psoriasis

Psoriasis is a chronic, immune-mediated disorder with cutaneous and systemic manifestations and substantial negative effects on patient quality of life. Psoriasis has a strong, albeit polygenic, genetic basis. Whereas approximately half of the accountable genetic effect of psoriasis maps to the major histocompatibility complex, >70 other loci have been identified, many of which implicate nuclear factor-κB, interferon signalling and the IL-23-IL-23 receptor axis. Psoriasis pathophysiology is characterized by abnormal keratinocyte proliferation and immune cell infiltration in the dermis and epidermis involving the innate and adaptive immune systems, with important roles for dendritic cells and T cells, among other cells. Frequent comorbidities are rheumatological and cardiovascular in nature, in particular, psoriatic arthritis. Current treatments for psoriasis include topical agents, photo-based therapies, traditional systemic drugs and biologic agents. Treatments can be used in combination or as monotherapy. Biologic therapies that target specific disease mediators have become a mainstay in the treatment of moderate-to-severe disease, whereas advances in the treatment of mild-to-moderate disease have been limited.

The Association of HLA-class I Genes and the Extent of Atherosclerotic Plaques in Patients with Psoriatic Disease

Objective.

To investigate the association between HLA susceptibility and disease severity markers and the extent of atherosclerosis in patients with psoriatic disease.

Methods.

White patients with psoriatic arthritis (PsA) and psoriasis without PsA (PsC) were recruited. An ultrasound of the carotid arteries was performed and the size of each atherosclerotic plaque was measured. The resulting score, the total plaque area (TPA), represented the extent of atherosclerosis. HLA genotyping was performed using sequence-specific oligonucleotide probes. The association between 10 HLA susceptibility and severity markers of PsC and PsA and the severity of atherosclerosis was assessed by ordinal logistic regression models adjusted for age, sex, and cardiovascular (CV) risk factors.

Results.

The study involved 411 patients (273 PsA, 138 PsC). Of them, 61.8% had at least 1 atherosclerotic plaque. HLA-B*13:02 and HLA-C*06:02 were associated with more severe atherosclerosis (age- and sex-adjusted OR 2.31, 95% CI 1.23–4.32 and OR 1.68, 95% CI 1.12–2.52, respectively). HLA-B*38:01 was associated with less severe atherosclerosis (OR 0.49, 95% CI 0.28–0.86). These associations remained statistically significant after adjusting for CV risk factors. Higher levels of erythrocyte sedimentation rate (ESR) were associated with more severe atherosclerosis (age- and sex-adjusted OR 1.33, p = 0.02). HLA-B*13:02–positive (p = 0.01) as well as HLA-C*06:02–positive (p = 0.008) patients had higher levels of ESR over time.

Conclusion.

HLA-C*06:02 and B*13:02 alleles are associated with a higher burden of atherosclerosis in patients with psoriatic disease. This association may be mediated by a higher level of systemic inflammation.

Genetic, Epigenetic and Pharmacogenetic Aspects of Psoriasis and Psoriatic Arthritis

There is a strong familial component to psoriatic disease as well as a complex array of genetic, immunologic, and environmental factors. The dominant genetic effect is located on chromosome 6p21.3 within the major histocompatibility complex region, accounting for one-third of genetic contribution. Genome-wide association studies (GWAS) identified additional genes, including skin barrier function, innate immune response, and adaptive immune response genes. To better understand disease susceptibility and progression requires replication in larger cohorts, fine-mapping efforts, new technologies, and functional studies of genetic variants, gene-gene interactions and gene-environmental interactions. New technologies available include next-generation sequencing, copy number variation analysis, and epigenetics.