Interleukin 17A: toward a new understanding of psoriasis pathogenesis

The role of IL-23 and the IL-23/TH 17 immune axis in the pathogenesis and treatment of psoriasis

Psoriasis is a chronic, immune-mediated disease affecting more than 100 million people worldwide and up to 2.2% of the UK population. The aetiology of psoriasis is thought to originate from an interplay of genetic, environmental, infectious and lifestyle factors. The manner in which genetic and environmental factors interact to contribute to the molecular disease mechanisms has remained elusive. However, the interleukin 23 (IL-23)/T-helper 17 (TH 17) immune axis has been identified as a major immune pathway in psoriasis disease pathogenesis. Central to this pathway is the cytokine IL-23, a heterodimer composed of a p40 subunit also found in IL-12 and a p19 subunit exclusive to IL-23. IL-23 is important for maintaining TH 17 responses, and levels of IL-23 are elevated in psoriatic skin compared with non-lesional skin. A number of agents that specifically inhibit IL-23p19 are currently in development for the treatment of moderate-to-severe plaque psoriasis, with recent clinical trials demonstrating efficacy with a good safety and tolerability profile. These data support the role of this cytokine in the pathogenesis of psoriasis. A better understanding of the IL-23/TH 17 immune axis is vital and will promote the development of additional targets for psoriasis and other inflammatory diseases that share similar genetic aetiology and pathogenetic pathways.

The association of autoimmune thyroid disease (AITD) with psoriatic disease: a prospective cohort study, systematic review and meta-analysis

OBJECTIVE

Autoimmune thyroid disease (AITD) and psoriatic disease share auto-immunological components. Few studies have investigated the link between both, yielding inconclusive results.

DESIGN

We assessed the association of AITD with psoriatic disease in a prospective cohort study and performed a systematic review and meta-analysis.

METHODS

8214 participants of the Rotterdam Study (RS) with thyroid peroxidase antibodies (TPO-Abs), thyroid-stimulating hormone (TSH) and/or free thyroxine (FT4) measurements and information on psoriatic disease were included. We performed logistic and Cox regression analyses and a systematic literature search in several electronic databases on AITD and psoriatic disease. We pooled odds ratios (ORs) of included studies using the Mantel-Haenszel method, while adding RS data on prevalent psoriatic disease.

RESULTS

Within the RS, we found no association between TPO-Ab positivity and psoriatic disease. There was a positive trend between TSH and prevalent psoriatic disease, and between FT4 and incident psoriatic disease, although not significant. Out of 1850 articles identified, seven were included in the systematic review and four in the meta-analysis. The risk of psoriatic disease (pooled OR) was 1.71 (confidence interval (CI): 1.27-2.31) for TPO-Ab positivity, 1.25 (CI: 1.14-1.37) for AITD and 1.34 (CI: 1.16-1.54) respectively, and 1.17 (CI: 1.03-1.32) for hypothyroidism and hyperthyroidism.

CONCLUSIONS

Our meta-analysis suggests that TPO-Ab positivity, hypothyroidism and hyperthyroidism might be associated with prevalent psoriatic disease. However, there are only few studies with large heterogeneity regarding psoriatic disease definition and indication of publication bias. Additional prospective data are needed to assess the association of AITD with incident psoriatic disease.

Small molecule therapy for managing moderate to severe psoriatic arthritis

INTRODUCTION

The majority of psoriatic arthritis (PsA) patients experience a good clinical response to conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) and biologic therapies (bDMARDs). However, treatment failure with these drugs can represent a relevant clinical problem. Moreover, in daily clinical practice, the appropriate identification of patients eligible for these agents can be conditioned by numerous aspects, mainly represented by comorbidities, such as history of malignancies, chronic and recurrent infectious diseases. Areas covered: We searched in the PUBMED database and review published data on the efficacy and safety profile of the small molecules, inhibitor of phosphodiesterase 4, apremilast, and of JAK/STAT pathways, tofacitinib, in PsA. Moreover, we report data on the other JAK inhibitor, baricitinib, and the A(3) adenosine receptors agonist, CF101, emerging by studies conducted in psoriasis patients. Expert opinion: In Psoriatic Arthritis, apremilast appears promising for PsA and recent studies have shown a good efficacy and an acceptable safety profile. Data on tofacitinib in PsA are limited. Studies on the small molecules, baricitinib and CF101 are still incomplete and limited to trials conducted in Rheumatoid Arthritis and in psoriasis. Further studies on small molecules and on their underlining mechanisms are advocated in PsA.

Psoriasis and the metabolic syndrome

Chronic plaque psoriasis is an immune-mediated inflammatory skin disease that is strongly associated with the clinical features of the metabolic syndrome (MetS), including abdominal obesity, hypertension, atherogenic dyslipidemia, type 2 diabetes, insulin resistance, and nonalcoholic fatty liver disease. The strength of these associations has been repeatedly confirmed by several observational studies. In particular, the prevalence of MetS in patients with psoriasis ranges from 20% to 50%, with a risk of having MetS is at least double in psoriatic patients compared with nonpsoriatic control individuals. MetS is also more common in patients with severe psoriasis than in those with mild skin disease. Emerging evidence now suggests that psoriasis and MetS share multiple metabolic risk factors, genetic background, and pathogenic pathways. The association between psoriasis and MetS has important clinical implications. Systemic conventional treatments should be used with caution in psoriatic patients with MetS, because they could adversely affect the coexisting metabolic disorders, especially in the case of their chronic use. Biologics appear to have a different safety profile compared with conventional treatments, and so they are usually tolerated. Collectively, dermatologists should pay close attention to the early recognition of coexisting metabolic disorders and give appropriate pharmacologic and nonpharmacologic (hypocaloric diet and regular exercise) recommendations to their patients.

A review article on brodalumab in the treatment of moderate-to-severe plaque psoriasis

Psoriasis is a chronic immune-mediated skin disorder affecting approximately 2-3% of the worldwide population. Recent advances in our understanding of the immunopathogenesis of psoriasis have resulted in novel therapeutic agents. IL-17, a pro-inflammatory cytokine, plays a pivotal role in psoriasis. Therapeutic agents targeting this cytokine have shown clinical effectiveness in the treatment of moderate-to-severe plaque psoriasis. Brodalumab, a human antibody against IL-17 receptor A, has been approved by the US FDA in February 2017, by the Japanese Pharmaceuticals and Medical Devices Agency in July 2016 and by the EMA in July 2017 for the treatment of moderate-to-severe psoriasis. This article reviews the published data relating to brodalumab for the treatment of moderate-to-severe plaque psoriasis.

Moderate to severe psoriasis treatment challenges through the era of biological drugs

Biological therapy has revolutionized moderate to severe psoriasis treatment. However, despite being more effective than conventional systemic treatments, some patients do not respond or lose response to biotechnological treatments or develop drug-antibodies, interfering with its safety and efficacy. There are also clinical forms of the disease and patient profiles for which is pending further scientific evidence for more sustained therapeutic interventions. The continuous and more detailed knowledge of psoriasis pathophysiology has allowed identifying new therapeutic targets, which is expected to help overcome the challenges of individualized psoriasis treatment.

The Clinical Significance of Increased Serum Proinflammatory Cytokines, C-Reactive Protein, and Erythrocyte Sedimentation Rate in Patients with Hidradenitis Suppurativa

Objectives

To assess inflammatory serum markers including serum proinflammatory cytokines, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) according to the clinical inflammatory activity of patients with hidradenitis suppurativa (HS).

Patients and Methods

Seventy-four patients with HS were studied based on the Hidradenitis Suppurativa-Physician Global Assessment (HS-PGA) score and Hurley staging system. Proinflammatory cytokines were measured using a multiplex cytokine assay. Twenty-two healthy volunteers were recruited.

Results

Serum interleukin- (IL-) 6, IL-23, soluble tumour necrosis factor alpha (TNF-α) receptor I (sTNF-RI), CRP, and ESR were different in the patients with HS compared with those in the healthy controls (P < 0.05). The levels of IL-1β, IL-6, IL-8, IL-10, IL-12p70, IL-17A, sTNF-RII, CRP, and ESR were significantly elevated according to inflammatory activity based on HS-PGA scores (r > 0.25, P < 0.05). The levels of IL-6 (r = 0.53, P < 0.001), CRP (r = 0.54, P < 0.001), and ESR (r = 0.60, P < 0.001) were especially well correlated with clinical inflammatory activity based on HS-PGA scores. The levels of IL-6, IL-8, sTNF-RI, sTNF-RII, CRP, and ESR were significantly elevated according to Hurley staging system.

Conclusions

Serum proinflammatory cytokines, CRP, and ESR are increased in relation to the clinical inflammatory activity of patients with HS compared with healthy controls. Serum IL-6, CRP, and ESR are effective biomarkers for evaluating the severity of HS.

Spotlight on brodalumab in the treatment of moderate-to-severe plaque psoriasis: design, development, and potential place in therapy

Brodalumab is a novel fully human immunoglobulin G2 monoclonal antibody that antagonizes the interleukin (IL)-17 pathway by binding with high affinity to human IL-17RA. The role of IL-17A in the pathogenesis of psoriasis, as well as the remarkable effectiveness of IL-17 inhibitors in the treatment of moderate-to-severe plaque psoriasis, is well established. The mechanism of action of brodalumab is unique in that it inhibits the IL-17 receptor compared to the two other currently FDA-approved IL-17 inhibitors, secukinumab and ixekizumab, which inhibit the IL-17A molecule itself. The efficacy of brodalumab in the treatment of moderate-to-severe plaque psoriasis has been demonstrated in phase 2 and 3 trials, and subsequently the FDA approved this medication in February 2017. Brodalumab was approved in Japan in July 2016 and approval is pending in Europe. The safety and adverse effects of brodalumab were reviewed across several clinical trials, which, similar to other IL-17 inhibitors, demonstrated increased rates of neutropenia and Candida infections. Brodalumab treatment, similar to ixekizumab and secukinumab, showed no improvement in inflammatory bowel disease patients, and on the contrary, more exacerbations were encountered. Suicidal ideation and behavior events have been reported with brodalumab treatment and are of significant concern. Brodalumab provides another highly effective treatment option for moderate-to-severe plaque psoriasis.

The critical role of macrophages in the pathogenesis of hidradenitis suppurativa

INTRODUCTION

Hidradenitis suppurativa (HS) is a painful chronic inflammatory disease with a prevalence between 1 and 4% of general population. The pathogenesis of HS long eluded scientists, but growing evidence suggests that it is a consequence of inflammatory dysregulation.

FINDINGS

Recent studies suggest that dysregulated immune response to skin flora and overexpression of inflammatory cytokines leads to chronic skin inflammation seen in HS. Macrophages are the most numerous inflammatory cells found in HS infiltrates and release numerous pro-inflammatory cytokines such as IL-23, and IL-1β and TNF-α, exacerbating the inflammation and contributing to the pathogenesis of HS. Furthermore, in HS, there is dysregulated function of other immune players closely associated with macrophage function including: matrix metalloproteases (MMP) 2 and 9 overexpression, toll-like receptor upregulation, impaired Notch signalling, NLRP3 inflammasome upregulation, and dysregulated keratinocyte function. Lifestyle factors including obesity and smoking also contribute to macrophage dysfunction and correlate with HS incidence.

CONCLUSIONS

The overexpression of pro-inflammatory cytokines and subsequent efficacy of anti-cytokine biologic therapies highlights the importance of managing macrophage dysfunction. Future therapies should target key molecular drivers of macrophage dysfunction such as TLR2 and NLRP3 overexpression.

IL-17A causes depression-like symptoms via NFκB and p38MAPK signaling pathways in mice: Implications for psoriasis associated depression

Psoriasis has been shown to be associated with an increased prevalence of comorbid major depression. IL-17A plays an important role in both depression and psoriasis. IL-17A has been shown to be elevated in systemic circulation of psoriatic patients. IL-17A released from different immune cells during psoriasis may be responsible for the development of neuropsychiatric symptoms associated with depression. Therefore, this study explored the association of systemic IL-17A with depression. The present study utilized imiquimod model of psoriatic inflammation as well as IL-17A administration in mice to investigate the effect of IL-17A on depression-like behavior. Psoriatic inflammation led to enhanced IL-17A expression in peripheral immune cells of both innate and adaptive origin. This was associated with increased NFκB/p38MAPK signaling and inflammatory mediators in different brain regions, and depression-like symptoms (as reflected by sucrose preference and tail suspension tests). The role of IL-17A was further confirmed by administering it alone for ten days, followed by assessment of the same parameters. IL-17A administration produced effects similar to psoriasis-like inflammation on neurobehavior and NFκB/p38MAPK pathways. Moreover, both NFκB and p38MAPK inhibitors led to attenuation in IL-17A associated with depression-like behavior via reduction in inflammatory mediators, such as MCP-1, iNOS, IL-6, and CXCL-2. Furthermore, anti-IL17A antibody also led to a reduction in imiquimod-induced depression-like symptoms, as well as NFκB/p38MAPK signaling. The present study shows that IL-17A plays an important role in comorbid depression associated with psoriatic inflammation, where both NFκB and p38MAPK pathways play significant roles via upregulation of inflammatory mediators in the brain.

Neutrophil-lymphocyte ratio, platelet-lymphocyte ratio and mean platelet volume in Japanese patients with psoriasis and psoriatic arthritis: Response to therapy with biologics

Recent studies indicate the presence of systemic inflammation in psoriatic patients, and this inflammatory status is significantly associated with a range of comorbidities. The aim of this study was to evaluate the clinical significance of novel inflammatory biomarkers, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR) and mean platelet volume (MPV) in Japanese patients with plaque-type psoriasis (PsV) and psoriatic arthritis (PsA). One hundred and eighty-six patients with PsV and 50 patients with PsA treated with biologics, including infliximab, adalimumab and ustekinumab, were retrospectively analyzed before and after treatment. At baseline, NLR and PLR, as well as C-reactive protein (CRP), were significantly higher in PsA patients than those in PsV patients, and a significant correlation was found between NLR and PLR. In PsV patients, the NLR-high and PLR-high subgroups exhibited significantly higher Psoriasis Area and Severity Index scores compared with the NLR-low and PLR-low subgroups, respectively, and the NLR-high subgroup also showed higher CRP levels. MPV value was negatively associated with the presence of arthritis, but its association with inflammation was less clear than that of NLR or PLR. After treatment of the patients with biologics for up to 12 months, NLR and PLR decreased promptly in parallel with a decrease of CRP, irrespective of the type of biologics used. Altogether, these results indicate that both NLR and PLR may be useful markers to evaluate systemic inflammation in psoriatic patients. They may serve as simple, convenient and cost-effective biomarkers to monitor the disease course after systemic therapy.

Systemic immune mechanisms in atopic dermatitis and psoriasis with implications for treatment

Atopic dermatitis (AD) and psoriasis are inflammatory skin diseases that negatively affect patients' quality of life. Although distinctions exist between these diseases, both are characterized by erythematous, thickened epidermal lesions that vary in intensity and affected body surface area. Early models of aetiology attributed symptoms of both diseases to cutaneous inflammation at lesion sites, but recent studies have established that activated immune mediators in the circulation drive disease severity. Activation of T helper 2 (Th2) and Th22 cells in the circulation appears to be the principal initiator of acute AD pathology, with the emergence of Th1 and Th17/interleukin (IL)-23 pathway activation marking the transition to a chronic state. The Th17/IL-23 pathway also has an important role in psoriasis. The role of systemic inflammation in AD and psoriasis is supported by the occurrence of non-cutaneous comorbidities that affect patients, most of which intensify morbidity and disability associated with lesional skin. Atopic dermatitis is associated with allergic disorders consisting of the "atopic march," whereas psoriasis is frequently accompanied by psoriatic arthritis. Patients with both disorders are at significantly higher risk of obesity, metabolic disorders, and cardiovascular diseases, all of which feature inflammatory components in their pathology models. These insights have led to novel therapeutics aimed at addressing psoriasis by targeting tumor necrosis factor- and Th17-related cytokine pathways. The success of these agents in psoriasis management is driving new therapeutic approaches for moderate-to-severe AD, including agents targeting the Th2 and Th17/Th22 cytokine pathways.

First-in-human randomized study of bimekizumab, a humanized monoclonal antibody and selective dual inhibitor of IL-17A and IL-17F, in mild psoriasis

AIMS

To assess safety, pharmacokinetics (PK) and clinical efficacy of bimekizumab (formerly UCB4940), a novel humanized monoclonal antibody and dual inhibitor of interleukin (IL)-17A and IL-17F, in subjects with mild plaque psoriasis.

METHODS

Randomized, double-blind, first-in-human study of bimekizumab in 39 subjects who received single-dose intravenous bimekizumab (8-640 mg) or placebo (NCT02529956).

RESULTS

Bimekizumab demonstrated dose-proportional linear PK and was tolerated across the dose range assessed. No subject discontinued due to treatment-emergent adverse events and no severe adverse events were reported. Bimekizumab demonstrated fast onset of clinically-meaningful effects on skin of patients with mild psoriasis as early as Week 2. Maximal improvements (100% or near 100% reductions from baseline) in all measures of disease activity were observed between Weeks 8-12 in subjects receiving 160-640 mg bimekizumab. The duration of effect at doses ≥160 mg was evident up to Weeks 12-20 after a single intravenous dose, dependent on endpoint.

CONCLUSIONS

This is the first study to demonstrate the safety, tolerability and clinical efficacy of a dual IL-17A and IL-17F inhibitor, in subjects with mild psoriasis. Bimekizumab showed fast onset of clinically-meaningful efficacy by Week 2, with a maximal or near-maximal magnitude of response that was maintained up to study Weeks 12-20. These findings support the continued clinical development of bimekizumab for diseases mediated by both IL-17A and IL-17F, including psoriasis.

Population Pharmacokinetic Modeling of Secukinumab in Patients With Moderate to Severe Psoriasis

Secukinumab is a human monoclonal antibody with demonstrated efficacy for moderate to severe psoriasis; it binds to and neutralizes interleukin (IL)-17A. The pharmacokinetic (PK) parameters of secukinumab were best described by a 2-compartment model. Only weight was included in the final model, as other covariates did not affect clinical relevance. The estimated serum clearance of secukinumab was 0.19 L/day, with interindividual variability (IIV) of 32% coefficient of variation (CV), and low total volume of distribution (central compartment volume, 3.61 L with IIV of 30% CV; peripheral compartment volume, 2.87 L with IIV of 18% CV). The bioavailability of secukinumab after subcutaneous dosing was approximately 73%, with an absorption rate of 0.18/day with IIV of 35% CV. The PK profile of secukinumab was linear, with no evidence of a dose dependence of clearance. Clearance and volume of secukinumab varied with body weight in an allometric relationship. The time to maximum serum concentration at steady state occurred approximately 6 days after dosing for both secukinumab 300 mg and secukinumab 150 mg. Overall, the PK properties of secukinumab were typical of a 150-kDa human IgG1 antibody interacting with a soluble target.

[Pathogenesis of psoriasis]

Psoriasis is an inflammatory T cell-mediated autoimmune disease of skin and joints that affects 2-4 % of the adult population and 0.1-1 % of children. Genetic susceptibility, environmental triggering factors, and innate immune processes initiate psoriasis pathogenesis that results in an adaptive autoreactive response. The T cell response is orchestrated by CD 8(+) T cells in the epidermis and by CD 4(+) T cells in the dermis that predominantly produce interleukin-17 (IL‑17). Research of the past 15 years unraveled cellular and molecular mechanisms as well as cytokines like TNF-α or IL‑23 that contribute to psoriatic inflammation. This knowledge has been translated into clinical practice and a number of antipsoriatic small molecules and immunobiologics are now available. Here, we discuss the current principles of psoriasis pathogenesis in the context of modern therapies.

Tofacitinib for the treatment of psoriasis

INTRODUCTION

The identification of a number of psoriasis-susceptibility genes and a better understanding of the pathogenesis of the intracellular metabolic pathways, have generated new perspectives on psoriasis treatment, in particular new compounds that inhibit certain intracellular proteins involved in the immune response. In contrast to biologic agents, these compounds block intracellular targets such as transcriptional factors or enzymes.

AREAS COVERED

Tofacitinib is a small molecule that acts as a reversible, competitive inhibitor of ATP in the ATP binding site of JAK proteins, determining their inactivation, thus prevents the downstream activation of the STAT proteins, which are then unable to up-regulate the pro-inflammatory genes implicated in psoriasis. The authors present an overview of Phases I - III clinical trials of tofacitinib for psoriasis based on peer-reviewed literature.

EXPERT OPINION

In clinical practice, it is important to assess the response of psoriasis to tofacitinib and identify possible clinical, genetic, and immune biomarkers to predict the response. Comorbidities associated with psoriasis, in particular metabolic syndrome and obesity, are also an important aspect of using tofacitinib in clinical practice. There are some evidences that a drug such as tofacitinib could be used to improve not only psoriasis, but also some of its important comorbidities.

Sexy again: the renaissance of neutrophils in psoriasis

Notwithstanding their prominent presence in psoriatic skin, the functional role of neutrophilic granulocytes still remains somewhat enigmatic. Sparked by exciting scientific discoveries regarding neutrophil functions within the last years, the interest in these short-lived cells of the innate immune system has been boosted recently. While it had been known for some time that neutrophils produce and respond to a number of inflammatory mediators, recent research has linked neutrophils with the pathogenic functions of IL-17, possibly in conjunction with the formation of NETs (neutrophil extracellular traps). Antipsoriatic therapies exert their effects, at least in part, through interference with neutrophils. Neutrophils also appear to connect psoriasis with comorbid diseases. However, directly tampering with neutrophil functions is not trivial as evinced by the failure of therapeutic approaches targeting redundantly regulated cellular communication networks. It has also become apparent that neutrophils link important pathogenic functions of the innate and the adaptive immune system and that they are intricately involved in regulatory networks underlying the pathophysiology of psoriasis. In order to advocate intensified research into the role of this interesting cell population, we here highlight some features of neutrophils and put them into perspective with our current view of the pathophysiology of psoriasis.

Secukinumab efficacy and safety in indian patients with moderate-to-severe plaque psoriasis: Sub-analysis from FIXTURE, a randomized, placebo-controlled, phase 3 study

Title:

Secukinumab efficacy and safety in Indian patients with moderate-to-severe plaque psoriasis: sub-analysis from FIXTURE (Full Year Investigative Examination of Secukinumab vs. Etanercept Using Two Dosing Regimens to Determine Efficacy in Psoriasis), a randomized, placebo-controlled, phase 3 study.

Background:

Evidence has suggested Interleukin (IL)-17A to be an important effector cytokine in the pathogenesis of psoriasis. Here, we report results for an Indian sub-population from a multinational study FIXTURE, designed to assess the safety, tolerability, and long-term efficacy of fully human anti–IL-17A monoclonal antibody secukinumab in patients with moderate-to-severe plaque psoriasis.

Materials and Methods:

In this double-dummy, placebo controlled, 52-weeks phase 3 study FIXTURE, 149 Indian patients were randomized 1:1:1:1 to receive secukinumab at a dose of 300 mg or 150 mg, etanercept, or placebo. The study objective was to show the superiority of secukinumab over placebo at week 12, vis-à-vis proportion of patients achieving a reduction of 75% or more from the baseline in the psoriasis area-and-severity index score (PASI 75) and a score of 0 (clear) or 1 (almost clear) on a 5-point modified investigator's global assessment (IGA mod 2011) (co-primary end points).

Results:

At week 12, 61.0% and 55.9% patients in secukinumab 300 mg and 150 mg groups, respectively, achieved PASI 75 response compared to 20.0% in the etanercept and 7.1% in the placebo groups. Similarly, IGA mod 2011 0 or 1 response was achieved by 43.9% and 20.6% in patients in the secukinumab 300 mg and 150 mg group, respectively, vs. 13.3% in the etanercept and 2.4% in the placebo groups at week 12. Likewise, higher proportions of patients in secukinumab 300 mg (41.5%) and 150 mg (20.6%) group were PASI 90 responders at week 12 than those in the etanercept (10.0%) or placebo (0.0%) groups. The incidences of adverse events (AEs), during the induction period were similar in all the treatment groups. Overall secukinumab was well-tolerated at both doses in the Indian sub-population.

Conclusion:

The results from the Indian sub-population suggest that secukinumab is an efficacious and safe drug for use in moderate-to-severe chronic plaque psoriasis

Secukinumab for ankylosing spondylitis and psoriatic arthritis

The treatment of ankylosing spondylitis (AS) and psoriatic arthritis (PsA) positively changed since the introduction of anti-TNFα drugs. These treatments were shown to reduce the symptoms and signs of the diseases and improve the quality of life. However, a variable percentage of patients do not respond to anti-TNFα or can exhibit a loss of response and, furthermore, despite anti-TNFα drugs' proven efficacy in reducing peripheral radiographic progression in PsA, the impact in reducing radiographic damage in AS is still debated. Recently, the discovery of new pathogenic mechanisms paved the way to the development of new drugs that target other pro-inflammatory cytokines. In particular, the inhibition of interleukin (IL)-17, which is the principal cytokine produced by Th17 lymphocytes, a pro-inflammatory subset involved in both inflammation and new bone formation in AS and PsA, demonstrated promising results. The new molecule secukinumab, an IL-17A inhibitor, showed its efficacy and safety in phase III randomized clinical trials in AS and PsA and is the first non-anti-TNFα biologic approved for the treatment of AS, providing a useful alternative treatment strategy in both diseases. The aim of this article was to review the pathophysiological basis, the efficacy and the safety of secukinumab treatment in AS and PsA patients.

Treatment challenges in the management of moderate-to-severe plaque psoriasis - role of secukinumab

Psoriasis is a chronic inflammatory skin disease that has a negative impact on psychosocial well-being and cardiometabolic health. Treatment options for moderate-to-severe psoriasis have expanded with the development of interleukin-17 (IL-17) inhibitors, the first of which is now available - secukinumab. Secukinumab is a fully human monoclonal immunoglobulin G1 κ antibody that selectively inhibits the ligand IL-17A. In head-to-head studies, it is more effective than etanercept and ustekinumab, particularly in achieving Psoriasis Area and Severity Index (PASI) 90/100 and achieving PASI 50/75 as early as week 4. No head-to-head trials are available for comparison of adalimumab to secukinumab. Significant improvement in health care-related quality of life was also observed using the dermatology quality index in clinical studies. Safety data for secukinumab is comparable to available biologics. Specific safety concerns for the use of secukinumab include its use in patients with inflammatory bowel disease, reversible transient neutropenia, in those with a latex allergy, and the occurrence of mild to moderate oral or genital candidiasis. Secukinumab is an effective and safe treatment option that achieves high clearance rates up to PASI 90 and 100 as monotherapy in cases of moderate-to-severe psoriasis. It may be particularly helpful in patients with psoriasis who have formed antidrug antibodies or failed other biologic agents and in patients with psoriatic arthritis or ankylosing spondylitis.

Palmoplantar pustular psoriasis (PPPP) is characterized by activation of the IL-17A pathway

BACKGROUND

Palmoplantar pustular psoriasis (PPPP) is a variant of psoriasis, which has significant negative impact on quality of life. The cellular and molecular inflammatory pathways involved in PPPP have not been well studied.

OBJECTIVE

Study the expression of cytokines and chemokines involved in the IL-17/IL-23 axis in palmoplantar pustular psoriasis and other difficult to treat psoriasis areas (palms, scalp, elbows and lower legs).

METHODS

Skin biopsies were performed on a total of 80 patients with PPPP, non-pustular palmoplantar psoriasis (NPPPP), or psoriasis located on elbows, knees and scalp as well as 10 healthy subjects. RT-PCR, immunohistochemistry and flow cytometry on cells extracted from skin biopsies were used to compare PPPP to other forms of psoriasis.

RESULTS

There was a significant (p<0.05) increase in the expression of IL-1β, IL-6, LL-37, IL-19, IL-17A, CXCL1 and CXCL2 in PPPP as compared to NPPPP. However, there was no significant difference in expression of IL-23 in PPPP as compared to NPPPP and other forms of psoriasis. The proportion of IL-22⁺ but not IL-17A⁺ mast cells was higher in PPPP as compared to NPPPP (p<0.05).

CONCLUSION

These results suggest that the IL-17A pathway may play a more important role in PPPP than in NPPPP.

Altered circulating T follicular helper cell subsets in patients with psoriasis vulgaris

Circulating T follicular helper (Tfh) cells in the blood are counterparts to conventional Tfh cells in germinal centres. Similarly to conventional Tfh cells, circulating Tfh cells provide helpful signals for B cells. Circulating Tfh cells can be divided into three subpopulations, including Tfh17 (CXCR3-CCR6+), Tfh1 (CXCR3+CCR6-), and Tfh2 (CXCR3-CCR6-) cells, based on differences in CXCR3 and CCR6 expression. Recent studies have demonstrated that alterations in circulating Tfh cell subsets have significant effects on the progression of numerous autoimmune diseases. To address the role of circulating Tfh cells in psoriasis, we used flow cytometry to analyse frequencies of circulating Tfh cell subsets and levels of IL-21 receptor (IL-21R) expression on B cells in 32 patients with psoriasis vulgaris and 13 sex- and age-matched healthy controls. We observed dynamic changes in Tfh17 cell frequency and disease severity in 10 psoriasis patients during a 6-month treatment. Our results demonstrate that the frequency of Tfh17 cells was significantly increased in psoriasis patients and was positively correlated with psoriasis area and severity index (PASI) score, a marker of disease severity (P<0.05). During the follow-up period, the frequencies of Tfh17 cells decreased, and reductions in PASI scores were observed. Moreover, IL-21R expression on B cells was significantly increased in patients with psoriasis vulgaris (P<0.05). Interestingly, IL-21R levels on B cells were correlated with both PASI score and the frequency of Tfh17 cells (P<0.05). In conclusion, this study is the first investigation of the distribution of circulating Tfh subsets in psoriasis. These results deepen our understanding of the immune state of psoriasis patients. Our data also indicate that Tfh17 cells may not be good biomarkers for diagnosing psoriasis but may be potential biomarkers of disease severity in psoriasis.

Efficacy of Secukinumab for Moderate-to-Severe Head and Neck Psoriasis Over 52 Weeks: Pooled Analysis of Four Phase 3 Studies

Introduction

Psoriasis affecting the head and neck can be difficult to treat, and the presence of extensive and highly visible lesions may result in substantial psychosocial burdens. Secukinumab, a monoclonal antibody that selectively targets interleukin-17A, provides rapid and sustained clearance of moderate-to-severe psoriasis. The objective of this study was to evaluate the efficacy of secukinumab on moderate-to-severe psoriasis affecting the head and neck. The safety and overall efficacy of secukinumab in patients with moderate-to-severe psoriasis will be described.

Methods

Data were pooled from four phase 3 studies. To be included in the head and neck analysis, patients were required to have Baseline head and neck Psoriasis Severity Area Index (PASI) scores ≥12 and psoriasis covering ≥10% of the head and neck. Secukinumab (300 or 150 mg) was administered at Baseline, Weeks 1, 2 and 3, and then every 4 weeks from Week 4 to 48.

Results

Secukinumab demonstrated high efficacy on the head and neck and the whole body. At Week 52, head and neck PASI 90/100 subscore responses were achieved by 76.0%/68.7% of patients receiving secukinumab 300 mg, respectively, and by 61.4%/53.1% of patients receiving secukinumab 150 mg, respectively. At Week 52, whole body composite PASI 90/100 responses were achieved by 68.1%/40.8% of patients receiving secukinumab 300 mg, respectively, and by 47.6%/24.3% of patients receiving secukinumab 150 mg, respectively. Secukinumab also improved Dermatology Life Quality Index scores.

Conclusion

Secukinumab provided robust and sustained efficacy for head and neck, and whole body psoriasis, over 52 weeks, with a favorable safety profile.

Funding

Novartis Pharmaceuticals Corporation.

Trial registration

ClinicalTrials.gov identifiers, NCT01365455, NCT01358578, NCT01555125, and NCT01636687.

Interleukin-17 inhibitors. A new era in treatment of psoriasis and other skin diseases

Psoriasis is a chronic skin disease caused by the excessive secretion of inflammatory cytokines. Available therapeutic options include biologic drugs such as tumor necrosis factor alpha inhibitors and interleukin 12/23 (IL-12/23) inhibitors. The recent discovery of IL-17, which contributes to development of psoriasis, opened new possibilities for further treatment modalities. Currently, one anti-IL17 biological agent is approved for the treatment – a fully human monoclonal antibody that targets IL-17A (secukinumab). Further clinical trials, including a humanized IgG4 specific for IL-17 (ixekizumab) and a fully human antibody that targets the IL-17 receptor A (brodalumab).

Neutrophil extracellular trap formation is increased in psoriasis and induces human β-defensin-2 production in epidermal keratinocytes

Neutrophil extracellular traps (NETs) have been implicated in the development of certain immune-mediated diseases, but their role in psoriasis has not been clearly defined. Human β-defensin-2 (HBD-2) is an important antimicrobial peptide overexpressed in psoriasis epidermis. We evaluated whether the amount of NETs is increased in psoriasis and determined the effect of NETs on HBD-2 production in epidermal keratinocytes. Using fluorescent microscopy, we found that patients with psoriasis (n = 48) had higher amount of NETotic cells in their peripheral blood compared to healthy controls (n = 48) and patients with eczema (n = 35). Psoriasis sera showed increased ability to induce NET formation in control neutrophils but normal NET degradation ability. The amount of NETs in the peripheral blood correlated with psoriasis disease severity. NETosis was also observed in the majority (18 of 20) of psoriasis skin specimens. Furthermore, NETs induced HBD-2 mRNA and protein production in keratinocytes, and immunohistochemical analysis confirmed strong expression of HBD-2 in psoriasis lesional skin. In summary, NET formation is increased in peripheral blood and lesional skin of psoriasis patients and correlates with disease severity. Additionally, NET-induced HBD-2 production may provide a novel mechanism for the decreased susceptibility of psoriasis plaques to microbial infections.

A systematic review and meta-analysis on Staphylococcus aureus carriage in psoriasis, acne and rosacea

Staphylococcus aureus might amplify symptoms in chronic inflammatory skin diseases. This study evaluates skin and mucosal colonization with S. aureus in patients with psoriasis, acne and rosacea. A systematic literature search was conducted. Both odds ratios (OR) for colonization in patients versus controls and the prevalence of colonization in patients are reported. Fifteen articles about psoriasis and 13 about acne (12 having a control group) were included. No study in rosacea met our inclusion criteria. For psoriasis, one study out of three controlled studies showed increased skin colonization (OR 18.86; 95 % confidence interval [CI] 2.20-161.99). Three out of the five studies that reported on nasal colonization showed significant ORs varying from 1.73 (95 % CI 1.16-2.58) to 14.64 (95 % CI 2.82-75.95). For acne one of the three studies that evaluated skin colonization reported a significant OR of 4.16 (95 % CI 1.74-9.94). A relation between nasal colonization and acne was not found. Limitations in study design and low sample sizes should be taken into consideration when interpreting the results. Colonisation with S. aureus seems to be increased in patients with psoriasis. This bacterial species, known for its potential to induce long-lasting inflammation, might be involved in psoriasis pathogenesis. Information on acne is limited. Prospective controlled studies should further investigate the role of S. aureus in chronic inflammatory skin diseases.

Current challenges and emerging drug delivery strategies for the treatment of psoriasis

INTRODUCTION

Psoriasis is a common skin disorder associated with physical, social, psychological and financial burden. Over the past two decades, advances in our understanding of pathogenesis and increased appreciation for the multifaceted burden of psoriasis has led to new treatment development and better patient outcomes. Yet, surveys demonstrate that many psoriasis patients are either undertreated or are dissatisfied with treatment. There are many barriers that need be overcome to optimize patient outcomes and satisfaction.

AREAS COVERED

This review covers the current challenges associated with each major psoriasis treatment strategy (topical, phototherapy, oral medications and biologics). It also reviews the challenges associated with the psychosocial aspects of the disease and how they affect treatment outcomes. Patient adherence, inconvenience, high costs, and drug toxicities are all discussed. Then, we review the emerging drug delivery strategies in topical, oral, and biologic therapy.

EXPERT OPINION

By outlining current treatment challenges and emerging drug delivery strategies, we hope to highlight the deficits in psoriasis treatment and strategies for how to overcome them. Regardless of disease severity, clinicians should use a patient-centered approach. In all cases, we need to balance patients' psychosocial needs, treatment costs, convenience, and effectiveness with patients' preferences in order to optimize treatment outcomes.

The Role of IL-17 in the Pathogenesis of Psoriasis and Update on IL-17 Inhibitors for the Treatment of Plaque Psoriasis

BACKGROUND

Major advances have been made in the understanding of the pathophysiology of psoriasis.

OBJECTIVES

The authors review the role of interleukin (IL) 17 in the pathogenesis of psoriasis and provide updates on approved and investigational therapies targeting IL-17 and the IL-17 receptor.

METHODS

A PubMed search was performed for relevant literature.

CONCLUSION

The IL-23/Th17 signaling pathway (including IL-17) plays a central role in the pathogenesis of psoriasis. Biologic agents that block IL-17 (secukinumab and ixekizumab) or its receptor (brodalumab) are effective and safe for the treatment of psoriasis.

Influence of different types of contact hypersensitivity on imiquimod-induced psoriasis-like inflammation in mice

It is currently believed that psoriasis and allergic contact dermatitis (ACD) are different diseases; however, they share clinical similarities. The involvement of T helper 17 (Th17) cells in these disorders provides a novel opportunity to investigate the relationship between them. The present study aimed to determine whether the same or overlapping inflammatory pathways are involved in the two diseases, and the influence of different types of ACD on psoriasis. Compound mouse models of Th1 or Th2‑type contact hypersensitivity (CHS) combined with imiquimod (IMQ)‑induced psoriasis‑like inflammation were established, in order to mimic the characteristics of ACD and psoriasis. Histopathology, immunohistochemistry and cytokine detection in blood serum and tissues were used to compare the differences between the mice treated with IMQ alone or IMQ combined with Th1 and Th2‑type CHS. As compared with the IMQ‑treated mice or IMQ-treated Th1‑type CHS mice, the mice with Th2‑type CHS treated with IMQ exhibited more serious psoriasis‑like inflammation with increased epidermal thickness and infiltrating cells in the derma. High mRNA expression levels of interleukin (IL)‑17, IL‑22, IL‑23, TNF‑α and RORγt were detected in back skin lesions. Additionally, high levels of IL‑17 and IL‑22 in blood serum were detected in IMQ‑treated mice combined with Th2‑type CHS. The mice treated with IMQ alone, and IMQ treatment combined with Th1‑type CHS had a comparable psoriasis‑like inflammatory response in the back skin. In conclusion, these data demonstrate that Th2‑type CHS exacerbated the IMQ‑treated psoriatic inflammation of mice via the IL‑23/IL‑17 axis. Th17 cells and associated pathways may link ACD and psoriasis. Therefore, patients with psoriasis should avoid contact with specific sensitizers, such as fragrance and rubber products, which may induce Th2 polarization.

Psoriatic arthritis and psoriasis: differential diagnosis

Psoriasis frequency ranges from 1 to 3 % in white population, and arthritis occurs in 10-40 % of psoriasis patients, representing a relevant health issue. Psoriatic arthritis (PsA) is an inflammatory arthropathy, associated with psoriasis, in which ocular-, intestinal-, metabolic-, and cardiovascular-related manifestations can variably coexist. In order to favor early PsA and psoriasis diagnosis, it is crucial to rule out other conditions that can resemble the disease and delay appropriate therapeutic approach. Therefore, the aim of this review is to focus on PsA and psoriasis differential diagnosis.

New and emerging biologic therapies for moderate-to-severe plaque psoriasis: mechanistic rationales and recent clinical data for IL-17 and IL-23 inhibitors

The development of effective and well-tolerated biologic therapies has advanced the management of psoriasis by enabling clinicians to treat underlying disease mechanisms. Biologics approved for the treatment of moderate-to-severe psoriasis include three tumor necrosis factor alpha inhibitors and an interleukin-12/interleukin-23 inhibitor. The establishment of the immunological basis of psoriasis has led to the development of biologic agents targeting specific downstream mediators in the psoriatic cascade. These drugs inhibit cytokines and cytokine signaling/transcription mediators like interleukin-17, which plays an important role in immunopathogenesis. Several interleukin-17 inhibitors are undergoing phase 3 clinical studies. In addition, biologics that selectively inhibit interleukin-23 have been assessed in phase 2 studies. This review describes how the dissection of pathways in the immunopathogenesis of psoriasis has led to the development of therapeutic agents and highlights the latest clinical efficacy, safety and tolerability data on new and emerging biologic therapies that selectively target interleukin-17 or interleukin-23.

IgE and FcεRI are highly expressed on innate cells in psoriasis

BACKGROUND

Although elevated serum IgE levels have been reported in psoriasis, the role of IgE in psoriasis still needs to be clarified.

OBJECTIVES

To analyse serum total IgE levels in addition to the presence and distribution of IgE and FcεRI in psoriatic lesions, and to investigate alteration of IgE and FcεRI after successful systemic treatment.

METHODS

Total serum IgE levels were determined using enzyme-linked immunosorbent assay. The expression and localization of IgE and FcεRI was investigated using immunohistochemistry and double immunofluorescence.

RESULTS

Elevated total serum IgE levels were found in 39% of patients with psoriasis. The levels of total serum IgE were significantly higher in male patients compared with female patients. Furthermore, total serum IgE levels decreased after successful systemic treatment. A positive correlation between IgE+ and FcεRI+ cells and a significant increase of these cells was found in psoriatic lesions when compared with normal skin. Interestingly, IgE+ and FcεRI+ cells decreased significantly after successful therapy with ustekinumab. IgE and FcεRI were coexpressed on mast cells, epidermal Langerhans cells, dermal dendritic cells, macrophages and a small number of neutrophils.

CONCLUSIONS

IgE might participate in the development of psoriasis by activating FcεRI-bearing cells.

IL-17A plays a central role in the expression of psoriasis signature genes through the induction of IκB-ζ in keratinocytes

In psoriasis lesions, a diverse mixture of cytokines is up-regulated that influence each other generating a complex inflammatory situation. Although this is the case, the inhibition of IL-17A alone showed unprecedented clinical results in patients, indicating that IL-17A is a critical inducer of psoriasis pathogenesis. To elucidate IL-17A-driven keratinocyte-intrinsic signaling pathways, we treated monolayers of normal human epidermal keratinocytes in vitro with a mixture of six cytokines (IL-17A, TNF-α, IL-17C, IL-22, IL-36γ and IFN-γ) involved in psoriasis to mimic the inflammatory milieu in psoriasis lesions. Microarray and gene set enrichment analysis revealed that this cytokine mixture induced similar gene expression changes with the previous transcriptome studies using psoriasis lesions. Importantly, we identified a set of IL-17A-regulated genes in keratinocytes, which recapitulate typical psoriasis genes exemplified by DEFB4A, S100A7, IL19 and CSF3, based on the differences in the expression profiles of cells stimulated with six cytokines versus cells stimulated with only five cytokines lacking IL-17A. Furthermore, a specific IL-17A-induced gene, NFKBIZ, which encodes IκB-ζ, a transcriptional regulator for NF-κB, was demonstrated to have a significant role for IL-17A-induced gene expression. Thus, we present novel in vitro data from normal human keratinocytes that would help elucidating the IL-17A-driven keratinocyte activation in psoriasis.

Therapeutic Effects of Erythroid Differentiation Regulator 1 on Imiquimod-Induced Psoriasis-Like Skin Inflammation

Psoriasis is a common skin disease accompanied by chronic inflammation. In previous studies, erythroid differentiation regulator 1 (ERDR1) was shown to have a negative correlation with proinflammatory cytokine IL-18. However, the role of ERDR1 in the inflammatory skin disease psoriasis has not been evaluated. In this study, to investigate the role of ERDR1 in psoriasis, recombinant ERDR1 was injected intraperitoneally into a psoriasis mouse model. Recombinant ERDR1 (rERDR1) significantly alleviated the symptoms of psoriasis-like skin inflammation and reduced the mRNA of various psoriasis-related markers, including keratin 14, S100A8, and Th17-related cytokines IL-17 and IL-22, suggesting that rERDR1 exerts therapeutic effects on psoriasis via the regulation of Th17 functions. Additionally, the expression of CCL20, a well-known Th17 attracting chemokine, was determined. CCL20 expression significantly decreased in the rERDR1-injected group compared with the vehicle (PBS)-injected group. CCR6 expression in the psoriatic lesional skin was also decreased by rERDR1 administration, implying the inhibition of CCR6-expressing Th17 cell chemotaxis via the downregulation of CCL20. Taken together, this study provides the first evidence that ERDR1 may be a potential therapeutic target for psoriasis.

Emerging drugs for psoriatic arthritis

INTRODUCTION

The majority of Psoriatic Arthritis patients experience a good clinical response to anti-Tumor Necrosis Factor (TNF)-α therapies. However, treatment failure with anti-TNF-α can represent a relevant clinical problem.

AREAS COVERED

We review the efficacy and safety profile of biological therapies that have been reported from randomized, controlled trials in phase II and phase III available in Pubmed Database for agents targeting IL-12/23p40 antibody (ustekinumab) and IL-17 (secukinumab), inhibitor of phosphodiesterase 4, (apremilast), and of JAK/STAT pathways (tofacitinib) and CTLA4 co-stimulation (abatacept) in Psoriatic Arthritis.

EXPERT OPINION

In Psoriatic Arthritis, main emerging drugs are represented by the fully human monoclonal IL-12/23p40 antibody, ustekinumab, the agent targeting IL-17, secukinumab, and the inhibitor of phosphodiesterase 4, apremilast. Results on T cell co-stimulation inhibition by abatacept are insufficient both in psoriasis and in PsA. In vitro investigations on JAK/STAT pathways in PsA suggest that tofacitinib could represent a further valuable therapeutic option. Emerging biological treatments other than anti-TNF agents, ustekinumab, secukinumab and apremilast appear promising for Psoriatic Arthritis and recent studies have showed a good efficacy and an acceptable safety profile; however, further and long-term studies are advocated.

Calcitonin Gene-Related Peptide-Exposed Endothelial Cells Bias Antigen Presentation to CD4+ T Cells toward a Th17 Response

Calcitonin gene-related peptide (CGRP) is a neuropeptide with well-established immunomodulatory functions. CGRP-containing nerves innervate dermal blood vessels and lymph nodes. We examined whether CGRP regulates the outcome of Ag presentation by Langerhans cells (LCs) to T cells through actions on microvascular endothelial cells (ECs). Exposure of primary murine dermal microvascular ECs (pDMECs) to CGRP followed by coculture with LCs, responsive CD4(+) T cells and Ag resulted in increased production of IL-6 and IL-17A accompanied by inhibition of IFN-γ, IL-4, and IL-22 compared with wells containing pDMECs treated with medium alone. Physical contact between ECs and LCs or T cells was not required for this effect and, except for IL-4, we demonstrated that IL-6 production by CGRP-treated pDMECs was involved in these effects. CD4(+) cells expressing cytoplasmic IL-17A were increased, whereas cells expressing cytoplasmic IFN-γ or IL-4 were decreased by the presence of CGRP-treated pDMECs. In addition, the level of retinoic acid receptor-related orphan receptor γt mRNA was significantly increased, whereas T-bet and GATA3 expression was inhibited. Immunization at the site of intradermally administered CGRP led to a similar bias in CD4(+) T cells from draining lymph node cells toward IL-17A and away from IFN-γ. Actions of nerve-derived CGRP on ECs may have important regulatory effects on the outcome of Ag presentation with consequences for the expression of inflammatory skin disorders involving Th17 cells.