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

Total glucosides of paeony for the treatment of psoriasis: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Psoriasis is a common chronic relapsing immune-mediated inflammatory disease, the prevalence of which has increased in recent years. At present, there are many treatment methods available for the condition, but the curative effect is unsatisfactory.

HYPOTHESIS/PURPOSE

This study aimed to evaluate the efficacy, adverse reactions, and recurrence rates of using paeoniflorin capsules for psoriasis treatment.

STUDY DESIGN

systematic review and meta-analysis.

METHODS

Randomized controlled trials comparing total glycosides of paeony (TGP) with other treatments for patients with psoriasis were retrieved by searching EMBASE, MEDLINE, and the Cochrane Central Register of Controlled Trials electronic databases. Cochrane bias risk tool was used to evaluate the quality of randomized controlled trial (RCT) methodology. The primary outcome measure is the effective number. Secondary outcomes included psoriasis area and severity index (PASI), adverse reactions, recurrence, and inflammatory biomarkers.

RESULTS

In all, 30 RCTs with 2,802 participants were included in this meta-analysis. The studies were generally of low methodological quality. Although there was no statistically significant difference between the use of TGP capsule alone and other monotherapies in the treatment of psoriasis (RR: 0.93; 95% CI: 0.76-1.15; p = 0.50), the addition of TGP to other therapies had an advantage over monotherapy with regard to the effective number (RR: 1.31; 95% CI: 1.26-1.37; p < 0.00001), PASI (RR: -3.40; 95% CI: -4.22,-2.57; p < 0.00001), adverse reactions, recurrence rate (RR: 0.42; 95% CI: 0.24-0.74; p = 0.002), and inflammatory inhibition (RR:-12.54; 95% CI: -18.50, -6.59; p < 0.0001).

CONCLUSIONS

TGP can be used to treat psoriasis with reduced adverse reactions and recurrence rates. However, the mechanism of TGP in psoriasis treatment requires to be evaluated further in high-quality, large-sample, and rigorous clinical studies.

Assessing the relative efficacy of interleukin-17 and interleukin-23 targeted treatments for moderate-to-severe plaque psoriasis: A systematic review and network meta-analysis of PASI response

INTRODUCTION

New generation biologics, including interleukin (IL)-17 and IL-23 inhibitors, have delivered higher rates of skin clearance than older treatments in head-to-head studies. However, studies comparing these new biologics directly to one another are limited.

OBJECTIVES

To compare the short-term efficacy of available (or imminently available) biologic and non-biologic systemic therapies for treating patients with moderate-to-severe plaque psoriasis.

METHODS

A systematic review was undertaken to identify randomised controlled trials evaluating biologic treatments, apremilast and dimethyl fumarate. MEDLINE, MEDLINE In-Process, Embase and the Cochrane Library were searched from the 1st January 2000 to 22nd November 2018. A Bayesian network meta-analysis (NMA) using a random-effects multinomial likelihood model with probit link and meta-regression to adjust for cross-trial variation in placebo responses compared the efficacy of interventions at inducing different levels of Psoriasis Area and Severity Index (PASI) response during the induction period. A range of sensitivity analyses was undertaken.

RESULTS

Seventy-seven trials (34,816 patients) were included in the NMA. The base-case analysis showed that all active treatments were superior to placebo. IL-17 inhibitors, guselkumab and risankizumab were found to be more efficacious than tildrakizumab, ustekinumab, all TNF inhibitors and non-biologic systemic treatments at inducing all levels of PASI response. In addition, brodalumab, ixekizumab and risankizumab were significantly more efficacious than secukinumab; no significant difference was found in the comparison with guselkumab. The greatest benefit of brodalumab, ixekizumab, guselkumab, and risankizumab was seen for PASI 90 and PASI 100 response. Results were consistent across all analyses.

CONCLUSIONS

In the NMA brodalumab, ixekizumab, risankizumab and guselkumab showed the highest levels of short-term efficacy. There were differences in efficacy between treatments within the same class. Longer-term analyses are needed to understand differences between these drugs beyond induction in what is a life-long condition.

Tildrakizumab in the treatment of psoriasis: latest evidence and place in therapy

Psoriasis is a chronic inflammatory disorder that is clinically characterized by scaly cutaneous plaques. New evidence suggests that dysregulation of interleukin (IL)-23, a key cytokine in the T-helper-17 pathway, plays a vital role in the development of psoriatic systemic inflammation. The novel biologic medication tildrakizumab is among the first drugs with specific action against IL-23 that has recently been approved by the United States Food and Drug Administration and the European Medicines Agency for moderate-to-severe psoriasis. Tildrakizumab has been shown in large randomized controlled trials to be effective in improving skin manifestations as well as enhancing quality of life outcomes in patients with psoriasis. Its simple dosing, prolonged duration of action, and mild adverse event profile make it a practical option for patients; however, only a small number of trials have investigated the clinical effectiveness of tildrakizumab, and long-term data regarding the drug's efficacy and safety are currently limited. Hence, further research is needed to better understand the risks and benefits of tildrakizumab. This review summarizes and analyzes phase I, phase II, and phase III clinical trials that investigate the mechanism, pharmacokinetics, efficacy, and safety of tildrakizumab. It also identifies areas in which additional studies are warranted to further elucidate the advantages of tildrakizumab over other biologic therapies.

Adaptive and Innate Immunity in Psoriasis and Other Inflammatory Disorders

Over the past three decades, a considerable body of evidence has highlighted T cells as pivotal culprits in the pathogenesis of psoriasis. This includes the association of psoriasis with certain MHC (HLA) alleles, oligoclonal expansion of T cells in some cases, therapeutic response to T cell-directed immunomodulation, the onset of psoriasis following bone marrow transplantation, or induction of psoriasis-like inflammation by T cells in experimental animals. There is accumulating clinical and experimental evidence suggesting that both autoimmune and autoinflammatory mechanisms lie at the core of the disease. Indeed, some studies suggested antigenic functions of structural proteins, and complexes of self-DNA with cathelicidin (LL37) or melanocytic ADAMTSL5 have been proposed more recently as actual auto-antigens in some cases of psoriasis. These findings are accompanied by various immunoregulatory mechanisms, which we increasingly understand and which connect innate and adaptive immunity. Specific adaptive autoimmune responses, together with our current view of psoriasis as a systemic inflammatory disorder, raise the question of whether psoriasis may have connections to autoimmune or autoinflammatory disorders elsewhere in the body. While such associations have been suspected for many years, compelling mechanistic evidence in support of this notion is still scant. This review sets into context the current knowledge about innate and adaptive immunological processes in psoriasis and other autoimmune or autoinflammatory diseases.

The Significance of IL-36 Hyperactivation and IL-36R Targeting in Psoriasis

Psoriasis is an immune-mediated inflammatory skin disease that involves mainly T helper (Th)17, Th1 and Th22 lymphocytes, which cause hyper-proliferation of the epidermis with aberrant differentiation of keratinocytes, and local production of chemokines and cytokines. These fuel a self-amplifying loop where these products act on T cells to perpetuate cutaneous inflammatory processes. Among the various inflammatory mediators involved, interleukin (IL)-36 cytokines are important for the recruitment and activation of neutrophils and Th17 cells in psoriatic skin. In particular, IL-36s induce chemokines and cytokines interfere with differentiation/cornification programs in the epidermis, as well as promote pathological angiogenesis and endothelial cell activation. IL-36 cytokines belong to the IL-1 family, and comprise IL-36α, IL-36β, and IL-36γ agonists as well as IL-36 receptor antagonist and IL-38 antagonists. IL-36 cytokines are up-regulated in psoriatic epidermis, and their expression is strongly induced by TNF-α and IL-17. Contrarily, IL-38 antagonist is downregulated, and its impaired expression may be relevant to the dysregulated inflammatory processes induced by IL-36. Here, we discuss on the pathogenic mechanisms leading to the altered balance of IL-36 agonists/antagonists and the significance of this dysregulation in psoriasis. Collection of the information will provide a theoretical basis for the development of novel therapeutic strategies based on IL-36 agonist/antagonist manipulation in psoriasis.

Safety of selective IL-23p19 inhibitors for the treatment of psoriasis

Psoriasis is a chronic disease that requires long‐term treatment. Consequently, understanding the safety and tolerability of any potential treatment over time is critical to effective prescribing. The biologic agents currently available for the treatment of psoriasis target a number of different inflammatory cytokines involved in psoriasis disease pathogenesis. The monoclonal antibodies tildrakizumab, guselkumab and risankizumab target the p19 subunit that is specific to interleukin (IL)‐23. This article reviews published data on the safety of these IL‐23p19 inhibitors in patients with psoriasis compared with other currently available biologic therapies. Data from randomized, placebo‐ and active‐controlled phase 3 clinical trials show tildrakizumab, guselkumab and risankizumab to have a favourable risk–benefit profile in patients with moderate to severe psoriasis. No significant safety concerns have been observed for any of these IL‐23p19 inhibitors in the data published to date. The most commonly reported adverse events (AEs) associated with these agents in phase 3 studies were upper respiratory tract infections. No increase was seen in rates of serious infections, malignancies or major adverse cardiovascular events, with no signals suggestive of an elevated risk of opportunistic infections, active tuberculosis or reactivation of latent tuberculosis infection, mucocutaneous Candida infections, triggering or worsening of inflammatory bowel disease, demyelinating disorders or suicidal ideation. Selectively targeting IL‐23p19 may help avoid AEs that have been associated with biologic agents with other mechanisms of action. Data from long‐term extension studies and patient registries will further establish the safety profile of IL‐23p19 inhibitors for the treatment of moderate to severe psoriasis in routine practice.

Efficacy and safety of risankizumab in Japanese patients with moderate to severe plaque psoriasis: Results from the SustaIMM phase 2/3 trial

Risankizumab, a humanized immunoglobulin G1 monoclonal antibody, selectively inhibits interleukin‐23, a key cytokine in the pathogenesis of psoriasis, by binding to its p19 subunit. In SustaIMM (ClinicalTrials.gov/NCT03000075), a phase 2/3, double‐blinded, placebo‐controlled study, Japanese patients with moderate to severe plaque psoriasis (n = 171) were stratified by bodyweight and concomitant psoriatic arthritis and randomized 2:2:1:1 to 75 mg risankizumab, 150 mg risankizumab, placebo with cross‐over to 75 mg risankizumab and placebo with cross‐over to 150 mg risankizumab. Dosing was at weeks 0, 4, 16, 28 and 40, with placebo cross‐over to risankizumab at week 16. The primary end‐point was 90% or more improvement from baseline in Psoriasis Area and Severity Index (PASI‐90) at week 16 for risankizumab versus placebo. Missing data were imputed as non‐response. All primary and psoriasis‐related secondary end‐points were met for both risankizumab doses (P < 0.001). At week 16, PASI‐90 responses were significantly higher in patients receiving 75 mg (76%) or 150 mg (75%) risankizumab versus placebo (2%). Corresponding response rates were 86%, 93% and 10% for static Physician Global Assessment (sPGA) score of clear/almost clear; 90%, 95% and 9% for PASI‐75; and 22%, 33% and 0% for PASI‐100, with significantly higher responses for both risankizumab doses versus placebo. Through week 52, PASI and sPGA responses increased or were maintained and treatment‐emergent adverse events were comparable across treatment groups. Both doses of risankizumab were superior to placebo in treating patients with moderate to severe plaque psoriasis. The safety profile was consistent with previous risankizumab trials, with no new or unexpected safety findings.

Guselkumab for the treatment of adults with moderate to severe plaque psoriasis

INTRODUCTION

Guselkumab is a subcutaneously administered monoclonal antibody that targets the IL-23p19 cytokine subunit and has been approved by the US FDA and the EMA for the treatment of moderate-to-severe psoriasis in adult patients. Areas covered: This review outlines the pharmacologic properties, efficacy and safety of guselkumab for the treatment of moderate-to-severe plaque psoriasis in adults. Expert opinion: In clinical trials, guselkumab markedly improved disease, regardless of topographical locations and patient subpopulations, with corresponding improvements in quality of life measures, and was generally well tolerated. Guselkumab has been shown to be more effective than adalimumab in phase III pivotal trials (VOYAGE 1 and VOYAGE 2) at both week 16 and week 24 for PASI75, PASI90, PASI100 and IGA(0/1); the corresponding PASI 90 response rates at week 16 were 73.3% vs 49.7% in VOYAGE 1 and 70.0% vs 46.8% in VOYAGE 2 (P < 0.001 in both). Guselkumab has been shown to be superior to secukinumab in PASI90 response rate at week 48 in a head-to-head trial (ECLIPSE); it is also successful in treating patients with incomplete responses to adalimumab (VOYAGE 2) and ustekinumab (NAVIGATE). Guselkumab may be effective in treating psoriatic arthritis, with several phase III trials ongoing.

The Use of Biologic Therapy in the Treatment of Acrodermatitis Continua of Hallopeau: A Review

Acrodermatitis continua of Hallopeau is a rare subtype of pustular psoriasis that presents as a sterile, pustular eruption commonly in the finger tips and toes. This disease inflicts both the skin and nail bed, and causes severe disfigurement of the distal phalanges. Because it is a variant of pustular psoriasis, acrodermatitis continua of Hallopeau is commonly managed with antipsoriatic medications. Common approaches to treatment include topical therapy (corticosteroids, vitamin D analogs, and calcineurin inhibitors), systemic therapy, and in more severe cases, biologic therapy. This review will discuss how acrodermatitis continua of Hallopeau is diagnosed and how it is managed, with a particular emphasis on the use of biologics.

Defective Induction of COX-2 Expression by Psoriatic Fibroblasts Promotes Pro-inflammatory Activation of Macrophages

Fibroblasts play an important role as members of the innate immune system through the secretion of COX-2-derived inflammatory mediators such as prostaglandin E₂ (PGE₂). However, it has been described that dermal fibroblasts behave like mesenchymal stem cells reducing lymphocyte recruitment and dendritic cell activation through PGE₂ release. As the role of fibroblasts in psoriasis remains poorly characterized, in the present study we have evaluated the possible influence of PGE₂ derived from dermal fibroblasts as modulator of the immune response in psoriatic skin. Our results indicate that under inflammatory conditions, psoriatic fibroblasts showed defective induction of COX-2, which resulted in diminished production of PGE₂, in contrast to healthy fibroblasts. This phenotype correlated with deficient c-Jun N-terminal kinase (JNK) activation, in accordance with the hypothesis that alterations in members of the JNK pathway are associated with psoriasis. Furthermore, conditioned medium from psoriatic fibroblasts promoted the polarization of monocytic cells toward a pro-inflammatory profile, effect that was mimicked in healthy fibroblasts after pre-incubation with indomethacin. These results are consistent with a prominent role of dermal fibroblasts in the regulation of inflammatory response through the participation of COX-derived metabolites. This resolutive behavior seems to be defective in psoriatic fibroblasts, offering a possible explanation for the chronification of the disease and for the exacerbation triggered by nonsteroidal anti-inflammatory drugs (NSAIDS) such as indomethacin.

Advances in Understanding the Immunological Pathways in Psoriasis

Psoriasis vulgaris is a chronic, immune-mediated, inflammatory, polygenic skin disorder affecting approximately 2% of the population. It has a great impact on quality of life; patients often experience depression, anxiety, stigma as well as suicidal behavior. Even though psoriasis is one of the most studied dermatological conditions, the pathogenesis of the disease is still not completely elucidated. The complex interactions between keratinocytes, dendritic cells, T-lymphocytes, neutrophils and mast cells are responsible for the histopathological changes seen in psoriasis. The pathogenic model leading to the formation of psoriatic plaques has however evolved a lot over the years. There is now enough evidence to support the role of interleukin (IL) -23, IL-17, IL-22, T helper (Th) -17 cells, Th-22 cells, T regulatory cells, transforming growth factor (TGF)-β1 and IL-10 in the pathogenesis of the disease. Moreover, several inflammatory and anti-inflammatory molecules are currently being investigated, some of them showing promising results. The aim of this paper is to look over the most recent advances in the immunological pathways involved in the pathogenesis of psoriasis vulgaris.

IFN-γ Reduces Epidermal Barrier Function by Affecting Fatty Acid Composition of Ceramide in a Mouse Atopic Dermatitis Model

IFN-γ is detected in chronic lesions of atopic dermatitis (AD); however, its specific role remains to be elucidated. An impaired stratum corneum barrier function is a hallmark of AD, and it is associated with a reduction in ceramides with long-chain fatty acids (FAs) in the stratum corneum. FA elongases, ELOVL1 and ELOVL4, are essential for the synthesis of these ceramides, together with ceramide synthase 3 (CerS3). We have previously shown that IFN-γ, but not other cytokines, induced the downregulation of these enzymes in cultured keratinocytes. Our aim was to investigate the in vivo role of IFN-γ in the lesional skin of AD by analyzing mouse dermatitis models. The local mRNA expression of IFN-γ increased in mite fecal antigen-induced AD-like dermatitis in NC/Nga mice but not in imiquimod-induced psoriasis-like dermatitis in BALB/c mice. The mRNA expression of ELOVL1 and ELOVL4 significantly decreased in AD-like dermatitis, whereas ELOVL1 increased in psoriasis-like dermatitis. The expression of CerS3 increased slightly in AD-like dermatitis, but it increased by 4.6-fold in psoriasis-like dermatitis. Consistently, the relative amount of ceramides with long-chain FAs decreased in AD-like dermatitis but not in psoriasis-like dermatitis. These results suggest that IFN-γ in the lesional skin may reduce ceramides with long-chain FAs by decreasing the expression of ELOVL. Thus, IFN-γ may contribute to the chronicity of AD by impairing barrier function.

Efficacy and safety of brodalumab in patients with psoriasis who had inadequate responses to ustekinumab: subgroup analysis of two randomized phase III trials

BACKGROUND

Brodalumab, a fully human anti-interleukin-17 receptor A monoclonal antibody, has demonstrated superior efficacy and safety over ustekinumab as induction therapy for moderate-to-severe psoriasis.

OBJECTIVES

To evaluate the efficacy and safety of brodalumab through week 52 in patients who had inadequate responses to ustekinumab.

METHODS

A subgroup analysis of the phase III AMAGINE-2/-3 double-blind randomized controlled trials was performed. Participants were aged 18-75 years and had a Psoriasis Area and Severity Index (PASI) ≥ 12, static Physician's Global Assessment score ≥ 3 and involvement of ≥ 10% body surface area. The studies were registered at ClinicalTrials.gov: AMAGINE-2, NCT01708603; AMAGINE-3, NCT01708629.

RESULTS

At baseline, patients with or without prior biologic experience who had an adequate response at week 16 on ustekinumab or brodalumab had lower rates of involved body surface area, PASI, prior biologic use, psoriatic arthritis and body mass index than patients who experienced inadequate response at or after week 16. Among patients who experienced inadequate response to ustekinumab, those rescued with brodalumab had PASI ≥ 75%, ≥ 90% and 100% improvement response rates of 72·6%, 58·1% and 36·3%, respectively, at week 52 compared with 61·7%, 25·5% and 5·4%, respectively, in patients who continued ustekinumab. Exposure-adjusted rates of treatment-emergent adverse events were similar among patients rescued with brodalumab (377·3 adverse events per 100 patient-years) and those who remained on ustekinumab (389·9 adverse events per 100 patient-years).

CONCLUSIONS

Among patients who experienced inadequate responses to ustekinumab, rescue with brodalumab improved skin clearance outcomes compared with continuing ustekinumab.

Spotlight on risankizumab and its potential in the treatment of plaque psoriasis: evidence to date

Psoriasis is a common chronic immune-mediated skin disease, with systemic involvement and significant impact in patients’ quality of life. Several highly specific treatments have been developed over the years, such as tumor necrosis factor-α inhibitors, a nonselective IL-23 inhibitor (ustekinumab), and most recently IL-17 inhibitors. Risankizumab is a monoclonal antibody which targets IL-23p19 without binding IL-12. This novel therapeutic approach is expected to have advantages over the recently approved anti-IL-17 agents, such as the avoidance of Candida infections and neutropenia. In addition, unlike ustekinumab, the selective inhibition of IL-23 may preserve IL-12-dependent functions such as protection against infections and tumor immune surveillance. Risankizumab showed an excellent efficacy when compared to placebo and ustekinumab, with higher Psoriasis Area Severity Index (PASI) 75, PASI 90, and PASI 100 rates, along with a convenient every 12-week maintenance dosing regimen. Overall, risankizumab was well tolerated and the most common adverse event was upper respiratory tract infection. In the near future, further data will be available not only in psoriasis but also in Crohn’s disease and psoriatic arthritis fields. Head-to-head trials comparing risankizumab with other IL-23 inhibitors and with IL-17 inhibitors will be crucial to reveal the role of risankizumab in the treatment of psoriasis.

The Immunologic Role of IL-17 in Psoriasis and Psoriatic Arthritis Pathogenesis

Psoriasis is a chronic, immune-mediated, inflammatory disease that is pathogenically driven by proinflammatory cytokines. This article reviews the immunologic role of interleukin (IL)-17, the major effector cytokine in the pathogenesis of psoriatic disease, along with the rationale for targeting the IL-17 cytokine family (IL-17A, IL-17F, and IL-17 receptor A) in the treatment of psoriasis and psoriatic arthritis. Emerging evidence indicates that major sources of IL-17A in patients with psoriatic disease are mast cells, γδ T cells, αβ T cells, and innate lymphoid cells in lesional skin and synovial fluid. Within the skin and joints, IL-17A acts on cellular targets, including keratinocytes, neutrophils, endothelial cells, fibroblasts, osteoclasts, chondrocytes, and osteoblasts, to stimulate production of various antimicrobial peptides, chemokines, and proinflammatory and proliferative cytokines, which, in turn, promote tissue inflammation and bone remodeling. The critical importance of the IL-23/IL-17A axis to the pathogenesis of psoriatic disease has resulted in many new biologic treatments targeting these cytokines. These biologics dramatically improve skin and joint symptoms in patients with moderate-to-severe psoriasis and psoriatic arthritis.

Gold lotion from citrus peel extract ameliorates imiquimod-induced psoriasis-like dermatitis in murine

BACKGROUND

Gold lotion (GL), a natural mixed product made from the peels of six citrus fruits, has recently been identified as possessing anti-oxidative, anti-inflammatory, and immunomodulatory effects. GL has been used to protect skin against UV-induced damage, but its activity against psoriasis, a chronic autoimmune skin disease caused by dysregulation between immune cells and keratinocytes, is not known. We therefore evaluated the effect of GL on imiquimod (IMQ)-induced psoriasis-like inflammation in mice.

RESULTS

GL treatment significantly attenuated IMQ-induced psoriasis-like symptoms in mice. The inflammatory cytokines upregulated by IMQ in skin lesions were also inhibited by feeding GL. In addition, GL treatment reduced the infiltration of CD4⁺ T cells/neutrophils in skin lesions and the percentage of IL-17-/IL-22-producing T cells in lymph nodes. Furthermore, GL impaired IMQ-induced type I interferon production by plasmacytoid dendritic cells (pDCs) in vitro.

CONCLUSION

Our results indicate GL can act to suppress the initiation of psoriasis and strongly suggest that GL may have potential to be applied to the treatment of psoriasis. © 2018 Society of Chemical Industry.

Antagonization of IL-17A Attenuates Skin Inflammation and Vascular Dysfunction in Mouse Models of Psoriasis

Besides skin inflammation, patients with severe psoriasis suffer from an increased risk of cardiovascular mortality. IL-17A plays a central role in the development of psoriasis and might connect skin and vascular disease. The aim of this study was to clarify whether anti-IL-17A therapy could also ameliorate the vascular dysfunction associated with severe psoriasis. We analyzed three murine models with varying severities of psoriasis-like skin disease concerning their vascular function and inflammation: (i) K14-IL-17A^ind/+ mice with keratinocyte-specific IL-17A overexpression and an early-onset severe psoriasis-like phenotype; (ii) homozygous CD11c-IL-17A^ind/ind and heterozygous CD11c-IL-17A^ind/+ mice overexpressing IL-17A in CD11c⁺ cells, leading to a delayed onset of moderate psoriasis-like skin disease; and (iii) the acute model of imiquimod-induced psoriasis-like skin inflammation. Similar to the severity of skin disease, vascular dysfunction correlated with peripheral IL-17A levels and neutrophil infiltration into the aortic vessel wall. Successful anti-IL-17A treatment of psoriatic skin lesions diminished peripheral oxidative stress levels, proinflammatory cytokines, and vascular inflammation. These data highlight the pivotal role of IL-17A linking the development of skin lesions and vascular disease in psoriasis. Anti-IL-17A therapy might thus represent a useful approach to attenuate and prevent vascular disease in psoriasis patients.

Loss-of-function mutations in caspase recruitment domain-containing protein 14 (CARD14) are associated with a severe variant of atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a highly prevalent chronic inflammatory skin disease that is known to be, at least in part, genetically determined. Mutations in caspase recruitment domain-containing protein 14 (CARD14) have been shown to result in various forms of psoriasis and related disorders.

OBJECTIVE

We aimed to identify rare DNA variants conferring a significant risk for AD through genetic and functional studies in a cohort of patients affected with severe AD.

METHODS

Whole-exome and direct gene sequencing, immunohistochemistry, real-time PCR, ELISA, and functional assays in human keratinocytes were used.

RESULTS

In a cohort of patients referred with severe AD, DNA sequencing revealed in 4 patients 2 rare heterozygous missense mutations in the gene encoding CARD14, a major regulator of nuclear factor κB (NF-κB). A dual luciferase reporter assay demonstrated that both mutations exert a dominant loss-of-function effect and result in decreased NF-κB signaling. Accordingly, immunohistochemistry staining showed decreased expression of CARD14 in patients' skin, as well as decreased levels of activated p65, a surrogate marker for NF-κB activity. CARD14-deficient or mutant-expressing keratinocytes displayed abnormal secretion of key mediators of innate immunity.

CONCLUSIONS

Although dominant gain-of-function mutations in CARD14 are associated with psoriasis and related diseases, loss-of-function mutations in the same gene are associated with a severe variant of AD.

Guselkumab for the Treatment of Psoriasis

Psoriasis is a common, chronic, immune-mediated, inflammatory skin disease with systemic involvement and significant impact on patients' quality of life. Several biologic treatments have been developed in recent decades, such as tumor necrosis factor (TNF)-α inhibitors, a non-selective interleukin (IL)-23 inhibitor (ustekinumab, which also inhibits IL-12), and-most recently-IL-17 inhibitors. Guselkumab is a novel biological therapy that selectively targets IL-23 and is the first-in-class selective IL-23 inhibitor approved to treat moderate-to-severe plaque psoriasis. These inhibitors are expected to have some advantages over the highly effective IL-17 inhibitors, as they do not worsen inflammatory bowel disease and are not involved in the development of candida infections. Additionally, selective inhibition of IL-23 may have additional benefits over ustekinumab as the IL-12-dependent cascades remain functional. These benefits include a decrease in IL-17A-producing T cells in the skin and the promotion of an anti-inflammatory effect through production of interferon-γ and IL-10. In terms of efficacy, guselkumab showed promising results in the treatment of psoriasis and psoriatic arthritis, although it did not show significant clinical improvement in rheumatoid arthritis. Studies in other inflammatory diseases and Crohn's disease are expected to begin soon. Overall, guselkumab was well tolerated; the most common adverse event was nasopharyngitis. Head-to-head studies comparing IL-23 inhibitors with agents in different classes, namely IL-17 inhibitors, will be crucial to establish the true role of these agents in psoriasis treatment.

Ustekinumab for the treatment of psoriasis and psoriatic arthritis: a drug evaluation and literature review

INTRODUCTION

Psoriasis (PsO) is an inflammatory disorder characterized by proliferation of keratinocytes, and it may be associated with a systemic inflammatory articular disorder, psoriatic arthritis (PsA). The presentations of PsO and PsA are heterogeneous, and our understanding of pathogenesis has led to a better understanding of the role of the interleukin (IL)-23/T-helper 17 (Th17) axis. Areas covered: Ustekinumab is a monoclonal antibody against IL-12 and IL-23. The pathogenesis of PsO and PsA is a multifactorial process involving genetic, environmental, and lifestyle factors. IL-23 signaling and activation of Th17 cells leads to a self-perpetuating inflammatory loop resulting in continuous keratinocyte proliferation and synovitis. Treatment options are varied, ranging from topical therapy to injection of targeted biologic disease-modifying antirheumatic drugs (bDMARDs). Evidence on the use of ustekinumab in the management of PsO is strong, but it is not as impressive in management of PsA. Expert opinion: IL-12/23 inhibition appears to be a good first-line option for plaque PsO, but efficacy in PsA does not compare favorably to IL-17 inhibition. In general, poorer responses to therapy with any bDMARD in PsA cohorts highlight psoriatic disease heterogeneity. Until new knowledge can remedy the failure of monotherapy, synergistic methods may have to be explored, including combination biologic therapy.

The Interplay Between Keratinocytes and Immune Cells in the Pathogenesis of Psoriasis

Psoriasis is a chronic inflammatory skin disease resulting from genetic, epigenetic, environmental, and lifestyle factors. To date, several immunopathogenic mechanisms of psoriasis have been elucidated, and, in the current model, the cross talk between autoreactive T cells and resident keratinocytes generates inflammatory and immune circuits responsible for the initiation, progression, and persistence of the disease. Several autoantigens derived from keratinocytes (i.e., LL37 cathelecidin/nucleic acid complexes, newly generated lipid antigens) have been identified, which may trigger initial activation of T cells, particularly IL-17-producing T cells, T helper (Th)1 and Th22 cells. Hence, lymphokines released in skin lesions are pivotal for keratinocyte activation and production of inflammatory molecules, which in turn lead to amplification of the local immune responses. Intrinsic genetic alterations of keratinocytes in the activation of signal transduction pathways dependent on T-cell-derived cytokines are also fundamental. The current review emphasizes the aberrant interplay of immune cells and skin-resident keratinocytes in establishing and sustaining inflammatory and immune responses in psoriasis.

p19-Targeting ILP Protein Blockers of IL-23/Th-17 Pro-Inflammatory Axis Displayed on Engineered Bacteria of Food Origin

IL-23-mediated Th-17 cell activation and stimulation of IL-17-driven pro-inflammatory axis has been associated with autoimmunity disorders such as Inflammatory Bowel Disease (IBD) or Crohn’s Disease (CD). Recently we developed a unique class of IL-23-specific protein blockers, called ILP binding proteins that inhibit binding of IL-23 to its cognate cell-surface receptor (IL-23R) and exhibit immunosuppressive effect on human primary blood leukocytes ex vivo. In this study, we aimed to generate a recombinant Lactococcus lactis strain which could serve as in vivo producer/secretor of IL-23 protein blockers into the gut. To achieve this goal, we introduced ILP030, ILP317 and ILP323 cDNA sequences into expression plasmid vector containing USP45 secretion signal, FLAG sequence consensus and LysM-containing cA surface anchor (AcmA) ensuring cell-surface peptidoglycan anchoring. We demonstrate that all ILP variants are expressed in L. lactis cells, efficiently transported and secreted from the cell and displayed on the bacterial surface. The binding function of AcmA-immobilized ILP proteins is documented by interaction with a recombinant p19 protein, alpha subunit of human IL-23, which was assembled in the form of a fusion with Thioredoxin A. ILP317 variant exhibits the best binding to the human IL-23 cytokine, as demonstrated for particular L.lactis-ILP recombinant variants by Enzyme-Linked ImmunoSorbent Assay (ELISA). We conclude that novel recombinant ILP-secreting L. lactis strains were developed that might be useful for further in vivo studies of IL-23-mediated inflammation on animal model of experimentally-induced colitis.

Inhibition of interleukin-12 and/or interleukin-23 for the treatment of psoriasis: What is the evidence for an effect on malignancy?

Immune cells and cytokines play an important role in the pathogenesis of psoriasis. Interleukin-12 (IL-12) and IL-23 promote cellular responses mediated by T cells, which contribute to an inflammatory loop responsible for the induction and maintenance of psoriatic plaques. Antibodies that inhibit IL-12/23 or IL-23 are key treatment options for patients with psoriasis. IL-12 and IL-23 also play a key role in immune responses to infections and tumors. A growing body of information from clinical trials, cohort studies, postmarketing reports, genetic studies and animal models provides insights into the potential biological relationships between IL-12/23 inhibition and malignancies. We summarize this information in tables and provide some context for the interpretation of these data with the goal of informing dermatologists who are using IL-12/23 or IL-23 inhibitors to treat patients with psoriasis.

T Cell Hierarchy in the Pathogenesis of Psoriasis and Associated Cardiovascular Comorbidities

The key role of T cells in the pathogenesis of cutaneous psoriasis has been well described in the last decade and the knowledge of the relative role of the different subsets of T cells in psoriasis pathogenesis has considerably evolved. Now, it is clear that IL-17A-producing T cells, including Th17/Tc17, have a central role in the pathogenesis of cutaneous psoriasis and therapies blocking the IL-17A pathway show high clinical efficacy. By contrast, the contribution of IFNγ-producing T cells has progressively become less clear because of the lack of efficacy of anti-IFNγ antibodies in clinical studies. In parallel, the role of CD8⁺ T cells specific for self-antigens has been revived and increasing evidence now indicates that in psoriatic skin the majority CD8⁺ T cells are present in the form of epidermal tissue-resident memory T cells. In the last years it also emerged the possibility of a contribution of T cell recirculation in the pathogenesis of psoriasis and its systemic manifestations. The aim of this review is to define a hierarchy for the different subsets of T cells in the T cell-mediated inflammatory cascade in psoriatic skin. This analysis will possibly help to distinguish the subsets that initiate the disease, those involved in the establishment of the self-sustaining amplification loop that leads to the cutaneous clinical manifestations and finally the subsets that act as downstream players in established lesions. Specific T cell subpopulations finally will be considered for their possible role in propagating inflammation at distant sites and for representing a link with systemic inflammation and cardiovascular comorbidities.

Psoriasis in Skin of Color: Insights into the Epidemiology, Clinical Presentation, Genetics, Quality-of-Life Impact, and Treatment of Psoriasis in Non-White Racial/Ethnic Groups

Psoriasis is a chronic inflammatory skin condition affecting diverse racial/ethnic groups throughout the world. Large population-based studies suggest that psoriasis occurs most often in individuals of European ancestry, followed by black and Hispanic individuals, although the true prevalence of psoriasis in non-white individuals is likely underestimated. Despite similarities in psoriasis between ethnic groups, there are notable differences in the presentation, quality-of-life impact, and treatment of psoriasis with important implications for the management of non-white individuals. Overall, heterogeneity in psoriasis susceptibility alleles, in combination with cultural and socioeconomic factors, may explain these differences. In this article, we review the epidemiology, clinical presentation, genetic polymorphisms, quality-of-life impact, and treatment nuances of psoriasis in patients with skin of color.

Human Leukocyte Antigen-Class I Alleles and the Autoreactive T Cell Response in Psoriasis Pathogenesis

Psoriasis is a complex immune-mediated inflammatory skin disease characterized by T-cell-driven epidermal hyperplasia. It occurs on a strong genetic predisposition. The human leukocyte antigen (HLA)-class I allele HLA-C*06:02 on psoriasis susceptibility locus 1 (PSORS1 on 6p21.3) is the main psoriasis risk gene. Other HLA-class I alleles encoding HLA molecules presenting overlapping peptide repertoires show associations with psoriasis as well. Outside the major histocompatibility complex region, genome-wide association studies identified more than 60 psoriasis-associated common gene variants exerting only modest individual effects. They mainly refer to innate immune activation and the interleukin-23/T_h/c17 pathway. Given their strong risk association, explaining the role of the HLA-risk alleles is essential for elucidating psoriasis pathogenesis. Psoriasis lesions develop upon epidermal infiltration, activation, and expansion of CD8⁺ T cells. The unbiased analysis of a paradigmatic Vα3S1/Vβ13S1-T-cell receptor from a pathogenic epidermal CD8⁺ T-cell clone of an HLA-C*06:02⁺ psoriasis patient had revealed that HLA-C*06:02 directs an autoimmune response against melanocytes through autoantigen presentation, and it identified a peptide form ADAMTS-like protein 5 as an HLA-C*06:02-presented melanocyte autoantigen. These data demonstrate that psoriasis is an autoimmune disease, where the predisposing HLA-class I alleles promote organ-specific inflammation through facilitating a T-cell response against a particular skin-specific cell population. This review discusses the role of HLA-class I alleles in the pathogenic psoriatic T-cell immune response. It concludes that as a principle of T-cell driven HLA-associated inflammatory diseases proinflammatory traits promote autoimmunity in the context of certain HLA molecules that present particular autoantigens.

Systemic Inflammation and Cardiovascular Comorbidity in Psoriasis Patients: Causes and Consequences

Psoriasis is a common inflammatory skin disease characterized by the appearance of red scaly plaques that can affect any part of the body. High prevalence, chronicity, disfiguration, disability, and associated comorbidity make it a challenge for clinicians of multiple specialties. Likewise, its complex pathogenesis, comprising inflammation, hyperproliferation, and angioneogenesis, intrigues numerous scientific disciplines, namely, immunology. From a clinical perspective, the severity of psoriasis is highlighted by its increased mortality, with cardiovascular diseases contributing the highest excess risk. From a scientific point of view, psoriasis has to be considered a systemic inflammatory condition, as blood biomarkers of inflammation are elevated and imaging techniques document sites of inflammation beyond the skin. While the association of psoriasis with cardiovascular diseases is now widely accepted, causes and consequences of this association are controversially discussed. This review comments on epidemiologic, genetic, and mechanistic studies that analyzed the relation between psoriasis and cardiovascular comorbidity. The hypothesis of psoriasis potentially being an independent cardiovascular risk factor, driving atherosclerosis via inflammation-induced endothelial dysfunction, will be discussed. Finally, consequences for the management of psoriasis with the objective to reduce the patients’ excess cardiovascular risk will be pointed out.

Molecular Mechanisms and Management of a Cutaneous Inflammatory Disorder: Psoriasis

Psoriasis is a complex chronic inflammatory cutaneous disorder. To date, robust molecular mechanisms of psoriasis have been reported. Among diverse aberrant immunopathogenetic mechanisms, the current model emphasizes the role of Th1 and the IL-23/Th17 axis, skin-resident immune cells and major signal transduction pathways involved in psoriasis. The multiple genetic risk loci for psoriasis have been rapidly revealed with the advent of a novel technology. Moreover, identifying epigenetic modifications could bridge the gap between genetic and environmental risk factors in psoriasis. This review will provide a better understanding of the pathogenesis of psoriasis by unraveling the complicated interplay among immunological abnormalities, genetic risk foci, epigenetic modification and environmental factors of psoriasis. With advances in molecular biology, diverse new targets are under investigation to manage psoriasis. The recent advances in treatment modalities for psoriasis based on targeted molecules are also discussed.

Models in the Research Process of Psoriasis

Psoriasis is an ancient, universal chronic skin disease with a significant geographical variability, with the lowest incidence rate at the equator, increasing towards the poles. Insights into the mechanisms responsible for psoriasis have generated an increasing number of druggable targets and molecular drugs. The development of relevant in vitro and in vivo models of psoriasis is now a priority and an important step towards its cure. In this review, we summarize the current cellular and animal systems suited to the study of psoriasis. We discuss the strengths and limitations of the various models and the lessons learned. We conclude that, so far, there is no one model that can meet all of the research needs. Therefore, the choice model system will depend on the questions being addressed.