Understanding the immune landscape in atopic dermatitis: The era of biologics and emerging therapeutic approaches

Interleukin antagonists for atopic dermatitis: a new era of therapy

INTRODUCTION

Over the last decade, increasing understanding of the immunopathogenesis of atopic dermatitis (AD) enabled the recognition of multiple therapeutic targets and subsequently the development of novel, highly effective systemic treatments, including interleukin (IL)-antagonists. To date, the IL-4Ra-inhibitor dupilumab and the IL-13 inhibitor tralokinumab have gained regulatory approval in Europe for the treatment of moderate-to-severe AD, while more than 70 new therapeutics are currently in development.

AREAS COVERED

In this review, we address the role of ILs in the pathogenesis of AD and provide an overview of the novel and investigational IL-antagonists, as regards their efficacy and safety on moderate-to-severe AD.

EXPERT OPINION

Current data have established IL-4 and IL-13 inhibitors as effective and safe for the treatment of moderate-to-severe AD, as regards the rapid control of flares as well as the long-term remission of the disease. Data regarding the efficacy and safety of other IL-inhibitors, including those targeting IL-31, IL-22, IL-33, IL-36 and IL-18, are accumulating. There is still an unmet need for real-world-evidence studies and head-to-head studies for both currently available and future agents in AD treatment. Establishing predictive biomarkers of treatment response in a disorder of such considerable heterogenicity might help physicians pursue a patient-tailored therapeutic response.

Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of PF-06817024 in Healthy Participants, Participants with Chronic Rhinosinusitis with Nasal Polyps, and Participants with Atopic Dermatitis: A Phase 1, Randomized, Double-Blind, Placebo-Controlled Study

PF-06817024 is a high affinity, humanized antibody that binds interleukin-33, a proinflammatory type 2 cytokine, and thereby has the potential to inhibit downstream type 2 inflammation. This Phase 1, randomized, placebo-controlled study was conducted in 3 parts to evaluate the safety, tolerability, pharmacokinetics (PK), immunogenicity, and pharmacodynamics of escalating single and limited repeat PF-06817024 doses in healthy participants (Part 1), a single dose of PF-06817024 in participants with chronic rhinosinusitis with nasal polyps (Part 2), and repeat doses of PF-06817024 in participants with moderate to severe atopic dermatitis (atoptic dermatitis; Part 3). PF-06817024 was generally well tolerated in all participant populations. Most participants experienced a treatment-emergent adverse event (healthy participants, 78.4% and 100%; participants with chronic rhinosinusitis with nasal polyps, 90.9% and 88.9%; and participants with atoptic dermatitis, 60.0% and 62.5% in the PF-06817024 and placebo groups, respectively). No substantial deviations from dose proportionality were observed for single intravenous doses of 10-1000 mg, indicating linear PK in healthy participants. Mean terminal half-life ranged from 83 to 94 days after single intravenous administration in healthy participants and was similar to that observed after administration in the studied patient populations. Incidences of antidrug antibodies in the studied populations were 10.8%, 9.1%, and 5.0% for healthy participants, participants with chronic rhinosinusitis with nasal polyps, and participants with atoptic dermatitis, respectively. In addition, dose-dependent increases were observed in total serum interleukin-33 levels of treated participants, indicating target engagement. Overall, the PK and safety profile of PF-06817024 supports further investigation of the drug as a potential treatment for allergic diseases.

Biologic and small-molecule therapy for treating moderate to severe atopic dermatitis: Mechanistic considerations

Atopic dermatitis (AD) is a complex and heterogeneous skin disease for which achieving complete clinical clearance for most patients has proven challenging through single cytokine inhibition. Current studies integrate biomarkers and evaluate their role in AD, aiming to advance our understanding of the diverse molecular profiles implicated. Although traditionally characterized as a TH2-driven disease, extensive research has recently revealed the involvement of TH1, TH17, and TH22 immune pathways as well as the interplay of pivotal immune molecules, such as OX40, OX40 ligand (OX40L), thymic stromal lymphopoietin, and IL-33. This review explores the mechanistic effects of treatments for AD, focusing on mAbs and Janus kinase inhibitors. It describes how these treatments modulate immune pathways and examines their impact on key inflammatory and barrier biomarkers.

Clinical and molecular effects of oral CCR4 antagonist RPT193 in atopic dermatitis: A Phase 1 study

BACKGROUND

RPT193 is an orally administered small molecule antagonist of the human C-C motif chemokine receptor 4 (CCR4) that inhibits the migration and downstream activation of T-helper Type 2 (Th2) cells. We investigated single- and multiple-ascending doses of RPT193 in healthy subjects, and multiple doses of RPT193 in subjects with moderate-to-severe atopic dermatitis (AD).

METHODS

This was a first-in-human randomized, placebo-controlled Phase 1a/1b monotherapy study (NCT04271514) to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and CCR4 surface receptor occupancy in eligible healthy subjects and subjects with moderate-to-severe AD. Clinical efficacy and skin biomarker effects of RPT193 monotherapy were assessed as exploratory endpoints in AD subjects.

RESULTS

In healthy (n = 72) and AD subjects (n = 31), once-daily RPT193 treatment was generally well tolerated, with no serious adverse events reported and all treatment-emergent adverse events reported as mild/moderate. In AD subjects, numerically greater improvements in clinical efficacy endpoints were observed with RPT193 monotherapy versus placebo up to the end of the treatment period (Day 29), with statistically significant improvement, compared to Day 29 and placebo, observed 2 weeks after the end of treatment (Day 43) on several endpoints (p < .05). Moreover, significant changes in the transcriptional profile were seen in skin biopsies of RPT193-treated versus placebo-treated subjects at Day 29, which were also significantly correlated with improvements in clinical efficacy measures.

CONCLUSIONS

To our knowledge, this is the first clinical study with an oral CCR4 antagonist that showed clinical improvement coupled with modulation of the cutaneous transcriptomic profile in an inflammatory skin disease.

Targeted Systemic Therapies for Adults with Atopic Dermatitis: Selecting from Biologics and JAK Inhibitors

Therapeutic options for people with moderate or severe atopic dermatitis refractory to topical therapy have rapidly expanded in recent years. These new targeted immunomodulatory agents-biologics and Janus kinase (JAK) inhibitors-have each demonstrated high levels of efficacy and acceptable safety in mostly placebo-controlled clinical trials for atopic dermatitis, but there is no universally applicable algorithm to help choose between them for a given patient. Hence, patients and physicians should utilize shared decision making, discussing efficacy, safety, mode of delivery, monitoring, costs, speed of onset, and other factors to reach individualized treatment decisions. In this review, we try to aid shared decision making by summarizing the efficacy, safety, and monitoring of biologics and oral JAK inhibitors for adults with atopic dermatitis. Network meta-analyses suggest that higher doses of abrocitinib and upadacitinib are more effective than biologics. They also show that, among biologics, dupilumab is likely more effective than tralokinumab and lebrikizumab. Biologics are generally considered safer than JAK inhibitors, although concerns about JAK inhibitors are mainly extrapolated from older generation JAK inhibitors used in higher-risk populations. We also outline evidence and considerations for choosing and using systemic immunomodulatory treatments for special populations including pregnant individuals, those with human immunodeficiency virus (HIV), hepatitis B and C, end stage kidney disease, and older adults.

Jiawei guomin decoction regulates the degranulation of mast cells in atopic dermatitis mice via the HIS/PAR-2 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Guomin decoction (GMD) is a traditional Chinese medicine commonly used in clinical practice. It has traditionally been used to treat all allergic diseases. Currently, Jiawei Guomin Decoction (JWGMD) is used to treat sensitive skin after initial therapy. Although it has a significant clinical therapeutic effect, the exact role of mast cell degranulation in treating atopic dermatitis (AD) is still unclear.

AIM OF THE STUDY

GMD and JWGMD can both treat allergic diseases, while JWGMD focuses on skin allergies. This study aims to explore the potential effect of JWGMD on the degranulation of mast cells in an AD mouse model induced by 2,4-dinitrofluorobenzene (DNFB) and investigate the effectiveness of JWGMD in alleviating disease progression to further provide specific therapeutic targets for treating AD.

MATERIALS AND METHODS

The scratching times and skin lesions of model mice induced by DNFB were observed, and skin tissues were collected for subsequent measurement. Histopathological changes in the back skin of mice were observed by haematoxylin eosin (H&E) staining, Toluidine blue staining was used to detect the degranulation of mouse skin mast cells, and the relationship between the expression of histamine (HIS), mast cell tryptase (MCT) and mast cell degranulation was analysed by enzyme-linked immunosorbent assay (ELISA). The expression of protease-activated receptor-2 (PAR-2), histamine 1 receptor (H1R), H2R, H4R and MCT proteins in AD mice was detected by Western blot (WB). Immunofluorescence assay (IFA) further confirmed the localization of PAR-2, H1R, H2R, H4R, and MCT proteins in the skin. Quantitative real-time PCR (qPCR) was used to determine PAR-2, H1R, H2R and H4R mRNA levels in skin lesions to further clarify the mechanism by which JWGMD amplifies mast cell degranulation in AD. In addition, a reliable ultrahigh-performance liquid chromatography-quadrupole electrostatic field orbitrap mass spectrometry (UPLC-QE-MS) nontargeted metabolomics analysis was performed to analyse the differences in metabolite abundance between GMD and JWGMD, and these results were used to identify the active components in JWGMD that may have antipruritic and anti-inflammatory properties and inhibit mast cell degranulation.

RESULTS

After intermittent stimulation with DNFB, the skin lesions showed extensive desquamation, dryness, scabbing, skin thickening, and slight bleeding. Both treatments alleviated this phenomenon and reduced the number of scratches, with JWGMD being the most effective. JWGMD can significantly reduce inflammatory cell infiltration, oedema, and some capillary neogenesis in mice and reduce the degranulation of mast cells. The ELISA results showed that JWGMD can increase the levels of MCT and HIS proteins. The WB and IFA results demonstrated that JWGMD reduced the expression levels of PAR-2, H1R, H4R, and MCT proteins in skin lesions, with protein localization mainly in the epidermal layer, while H2R protein levels were increased and mainly localized in the dermis. In addition, JWGMD downregulates the mRNA expression of PAR-2, H1R, H2R, and H4R. Interestingly, through UPLC-QE-MS nontargeted metabolomic analysis, we detected the anti-inflammatory and antiallergy active substances in JWGMD, such as methyl eugenol, dictamnine and sinapine.

CONCLUSIONS

JWGMD may alleviate itching through methyl syringol, dictamnine, sinapine and other substances, and its mechanism may be related to inhibiting the HIS/PAR-2 pathway in AD model mice and further regulating the self-amplification of mast cell degranulation. JWGMD is a potential drug for treating AD. Therefore, it deserves continuous attention and research.

A Bispecific, Tetravalent Antibody Targeting Inflammatory and Pruritogenic Pathways in Atopic Dermatitis

Inhibition of IL-4/IL-13 signaling has dramatically improved the treatment of atopic dermatitis (AD). However, in many patients, clinical responses are slow to develop and remain modest. Indeed, some symptoms of AD are dependent on IL-31, which is only partially reduced by IL-4/IL-13 inhibition. Thus, there is an unmet need for AD treatments that concomitantly block IL-4/IL-13 and IL-31 pathways. We engineered NM26-2198, a bispecific tetravalent antibody designed to accomplish this task. In reporter cell lines, NM26-2198 concomitantly inhibited IL-4/IL-13 and IL-31 signaling with a potency comparable with that of the combination of an anti-IL-4Rα antibody (dupilumab) and an anti-IL-31 antibody (BMS-981164). In human PBMCs, NM26-2198 inhibited IL-4-induced upregulation of CD23, demonstrating functional binding to FcγRII (CD32). NM26-2198 also inhibited the secretion of the AD biomarker thymus and activation-regulated chemokine (TARC) in blood samples from healthy human donors. In male cynomolgus monkeys, NM26-2198 exhibited favorable pharmacokinetics and significantly inhibited IL-31-induced scratching at a dose of 30 mg/kg. In a repeat-dose, good laboratory practice toxicology study in cynomolgus monkeys, no adverse effects of NM26-2198 were observed at a weekly dose of 125 mg/kg. Together, these results justify the clinical investigation of NM26-2198 as a treatment for moderate-to-severe AD.

Unraveling Atopic Dermatitis: Insights into Pathophysiology, Therapeutic Advances, and Future Perspectives

Atopic dermatitis (AD) is an inflammatory skin condition that frequently develops before the onset of allergic rhinitis or asthma. More than 10% of children are affected by this serious skin condition, which is painful for the sufferers. Recent research has connected the environment, genetics, the skin barrier, drugs, psychological factors, and the immune system to the onset and severity of AD. The causes and consequences of AD and its cellular and molecular origins are reviewed in this paper. The exploration of interleukins and their influence on the immunological pathway in AD has been facilitated by using relevant biomarkers in clinical trials. This approach enables the identification of novel therapeutic modalities, fostering the potential for targeted translational research within the realm of personalized medicine. This review focuses on AD's pathophysiology and the ever-changing therapeutic landscape. Beyond the plethora of biologic medications in various stages of approval or development, a range of non-biologic targeted therapies, specifically small molecules, have emerged. These include Janus kinase (JAK) inhibitors like Baricitinib, Upadacitinib, and Abrocitinib, thus expanding the spectrum of therapeutic options. This review also addresses the latest clinical efficacy data and elucidates the scientific rationale behind each targeted treatment for atopic dermatitis.

Novel Immunopharmacological Drugs for the Treatment of Allergic Diseases

The exponential rise in the prevalence of allergic diseases since the mid-twentieth century has led to a genuine public health emergency and has also fostered major progress in research on the underlying mechanisms and potential treatments. The management of allergic diseases benefits from the biological revolution, with an array of novel immunomodulatory therapeutic and investigational tools targeting players of allergic inflammation at distinct pathophysiological steps. Prominent examples include therapeutic monoclonal antibodies against cytokines, alarmins, and their receptors, as well as small-molecule modifiers of signal transduction mainly mediated by Janus kinases and Bruton's tyrosine kinases. However, the first-line therapeutic options have yet to switch from symptomatic to disease-modifying interventions. Here we present an overview of available drugs in the context of our current understanding of allergy pathophysiology, identify potential therapeutic targets, and conclude by providing a selection of candidate immunopharmacological molecules under investigation for potential future use in allergic diseases.

Baseline Demographics, Comorbidities, Treatment Patterns and Burden of Atopic Dermatitis in Adults and Adolescents from the GLOBOSTAD Long-Term Observational Study

INTRODUCTION

Insights into real-world treatment of atopic dermatitis (AD) are relevant to clinical decision making. The aim of this analysis was to characterize patients who receive dupilumab for AD in a real-world setting.

METHODS

The GLOBOSTAD registry is an ongoing, longitudinal, prospective, observational study of patients with AD who receive dupilumab according to country-specific prescribing information. We report baseline characteristics, comorbidities and treatment patterns for patients enrolled from July 11, 2019 to March 31, 2022. Analyses are descriptive; no formal statistical comparisons were performed.

RESULTS

Nine hundred fifty-two adults and adolescents were enrolled in GLOBOSTAD. Patients had a high disease burden before starting dupilumab: (mean [standard deviation]) percent body surface area affected (44.8 [24.42]), Eczema Area and Severity Index total score (24.8 [12.95]), SCORing Atopic Dermatitis total score (60.5 [16.34]), Patient-Oriented Eczema Measure total score (19.7 [6.37]) and Dermatology Life Quality Index total score (13.7 [7.02]). Overall, 741 (77.8%) patients reported ≥ 1 type 2 inflammatory comorbidities, most frequently allergic rhinitis (492 [51.7%]), asthma (323 [33.9%]), food allergy (294 [30.9%]) or another allergy (274 [28.8%]). In the previous 12 months, 310 (32.6%) patients had received systemic non-steroidal immunosuppressants and 169 (17.8%) systemic corticosteroids; 449 (47.2%) had received topical corticosteroids, most commonly potent topical corticosteroids; 141 (14.8%) had received topical calcineurin inhibitors and 32 (3.4%) ultraviolet therapy. Most (713 [74.9%]) patients started dupilumab because of prior treatment failure.

CONCLUSION

Patients enrolled in GLOBOSTAD demonstrated considerable multidimensional burden of disease across AD signs, symptoms and quality of life despite previous use of systemic and non-systemic AD treatments.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT03992417. Video Abstract.

Tralokinumab therapy for moderate-to-severe atopic dermatitis: Clinical outcomes with targeted IL-13 inhibition

Atopic dermatitis (AD) is a chronic, inflammatory, intensely pruritic skin disorder associated with significant patient burden. Interleukin (IL)-13 is a cytokine that acts as a driver of immune dysregulation, skin-barrier dysfunction, and microbiome dysbiosis that characterizes AD, and is consistently overexpressed in AD skin. Tralokinumab is a fully human immunoglobulin (Ig) G4 monoclonal antibody that binds specifically to IL-13 with high affinity, thereby inhibiting subsequent downstream IL-13 signaling. Three pivotal phase 3 clinical trials demonstrated that tralokinumab 300 mg every other week, as monotherapy or in combination with topical corticosteroids as needed, provides significant improvements in signs and symptoms of moderate-to-severe AD, as measured by Investigator's Global Assessment 0/1 (clear/almost clear) and Eczema Area and Severity Index-75 at Week 16. Improvements were observed soon after tralokinumab initiation and were maintained over 52 weeks of therapy. Tralokinumab significantly improved patient-reported outcomes such as itch and sleep, and demonstrated a safety profile comparable with placebo; conjunctivitis during tralokinumab therapy was generally mild. Similar results were observed in a phase 3 adolescent trial. The role of IL-13 in the pathophysiology of AD justifies a targeted approach and a wealth of clinical data supports tralokinumab as a new therapeutic option for people with moderate-to-severe AD.

Lebrikizumab for the Treatment of Moderate-to-Severe Atopic Dermatitis

Atopic dermatitis (AD) is a common, heterogeneous, inflammatory skin disorder characterized by chronic or relapsing eczematous lesions with intense pruritus and discomfort. Affected patients often experience significant impairment in their quality of life, and the treatment of moderate-to-severe AD forms remains challenging. In the past few decades, increasing knowledge on the AD pathogenesis has driven the development of novel targeted therapies. Interleukin (IL)-13 plays a central and pleiotropic role in AD pathogenesis, contributing directly or indirectly to epidermal barrier disfunction, type-2 inflammation, dysbiosis, fibrosis, and itch response. For this reason, agents selectively targeting IL-13, such as lebrikizumab, emerged as a potential therapy for AD. This article reviews the current evidence about lebrikizumab in the management of AD. The phase II and phase III trials seem to corroborate efficacy of lebrikizumab in the treatment of moderate-to-severe AD, as shown by significant improvement of Eczema Area and Severity Index, body surface area, and pruritus scores. Also, lebrikizumab demonstrated favorable safety and tolerability profiles, with the majority of patients experiencing no significant adverse events. Lebrikizumab seems to be a promising emerging targeted biological agent for patients with moderate-to-severe AD. More data on the long-term efficacy and safety, head-to-head comparisons with other agents, and real-world evidence will help to clarify its place in therapy in AD.

[Algoritmo de tratamiento de la dermatitis atópica en Perú. Consenso de expertos]

Objective

Atopic dermatitis is a chronic, systemic, relapsing disease with dermatological manifestations, which imposes a high burden on patients, families and the health care system and has a high psychological, social, and economic impact and on the quality of life of patients. It mainly affects the pediatric population and, to a lesser extent, the adult population. The clinical presentation varies according to the age and evolution of the disease, and currently there are multiple pharmacological and non-pharmacological therapies available for the symptomatic management of patients.

Methods

To present an algorithm for the management of atopic dermatitis, proposed as a series of recommendations on the management, diagnosis, education, and follow-up of these patients.

Results

A consensus was reached using the nominal group technique. The methodology was developed in 7 phases, including: posing the research questions, literature search, an initial proposal of recommendations, elaboration of the final recommendations and the management algorithm with three voting cycles, consensus was established with 80% favorability.

Conclusions

The result of the consensus process is a management algorithm for patients with mild, moderate/severe atopic dermatitis derived from expert recommendations. The algorithm establishes diagnostic and treatment criteria and provides updated recommendations, including all therapeutic alternatives available in Peru for the management of patients with mild, moderate, and severe atopic dermatitis.

Binding, Neutralization and Internalization of the Interleukin-13 Antibody, Lebrikizumab

INTRODUCTION

IL-13 is the primary upregulated cytokine in atopic dermatitis (AD) skin and is the pathogenic mediator driving AD pathophysiology. Lebrikizumab, tralokinumab and cendakimab are therapeutic monoclonal antibodies (mAb) that target IL-13.

METHODS

We undertook studies to compare in vitro binding affinities and cell-based functional activities of lebrikizumab, tralokinumab and cendakimab.

RESULTS

Lebrikizumab bound IL-13 with higher affinity (as determined using surface plasma resonance) and slower off-rate. It was more potent in neutralizing IL-13-induced effects in STAT6 reporter and primary dermal fibroblast periostin secretion assays than either tralokinumab or cendakimab. Live imaging confocal microscopy was employed to determine the mAb effects on IL-13 internalization into cells via the decoy receptor IL-13Rα2, using A375 and HaCaT cells. The results showed that only the IL-13/lebrikizumab complex was internalized and co-localized with lysosomes, whereas IL-13/tralokinumab or IL-13/cendakimab complexes did not internalize.

CONCLUSION

Lebrikizumab is a potent, neutralizing high-affinity antibody with a slow disassociation rate from IL-13. Additionally, lebrikizumab does not interfere with IL-13 clearance. Lebrikizumab has a different mode of action to both tralokinumab and cendakimab, possibly contributing to the clinical efficacy observed by lebrikizumab in Ph2b/3 AD studies.

The Essential Role of microRNAs in Inflammatory and Autoimmune Skin Diseases-A Review

The etiopathogenesis of autoimmune skin diseases is complex and still not fully understood. The role of epigenetic factors is emphasized in the development of such diseases. MicroRNAs (miRNAs), a group of non-coding RNAs (ncRNAs-non-coding RNAs), are one of the important post-transcriptional epigenetic factors. miRNAs have a significant role in the regulation of the immune response by participating in the process of the differentiation and activation of B and T lymphocytes, macrophages, and dendritic cells. Recent advances in research on epigenetic factors have provided new insights into the pathogenesis and potential diagnostic and therapeutic targets of many pathologies. Numerous studies revealed a change in the expression of some microRNAs in inflammatory skin disorders, and the regulation of miRNA expression is a promising therapeutic goal. This review presents the state of the art regarding changes in the expression and role of miRNAs in inflammatory and autoimmune skin diseases, including psoriasis, atopic dermatitis, vitiligo, lichen planus, hidradenitis suppurativa, and autoimmune blistering diseases.

TRPA1 is involved in the inhibitory effect of Ke-teng-zi on allergic contact dermatitis via MAPK and JAK/STAT3 signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

The seeds of Entada phaseoloides (Linn.) Merr. commonly named "Ke-teng-zi" is a traditional Chinese folk medicine and reported to treat dermatitis, spasm, and headache. However, the exact effect and the mechanism of Ke-teng-zi on the treatment of dermatitis is unclear.

AIM OF THE STUDY

To elucidate the antipruritic effect and molecular mechanisms of Ke-teng-zi on the treatment of allergic contact dermatitis (ACD).

MATERIALS AND METHODS

The main components of the n-butanol fraction of 70% ethanol extract from Ke-teng-zi (abbreviated as KB) were analyzed by HPLC. The chloroquine (CQ)-induced acute itch and squaraine dibutyl ester (SADBE)-induced ACD chronic itch in mice was established, and the TNF-α/IFN-γ stimulated Human keratinocytes (HaCaT) were used to evaluate the antipruritic and anti-inflammatory effects of KB. Behavioral tests, lesion scoring, and histology were also examined. The expression levels of molecules in MAPK and JAK/STAT3 pathways, the mRNA levels of chemokines and cytokines in both the skin of ACD mice and the HaCaT cells were detected by western blot and qPCR. Furthermore, whole-cell patch-clamp recordings in TRPA1-tranfected HEK293T cells were used to elucidate the effect of KB on TRPA1 channels. TRPA1 siRNA was used to evaluate the role of TRPA1 in the anti-inflammatory effect of KB in keratinocytes.

RESULTS

The main compounds in KB could bind to the active sites of TRPA1 mainly through hydrogen bond and hydrophobic bond interactions. KB could inhibit the scratching behavior in CQ-induced acute itch, and the inhibitory effect of KB was blocked by TRPA1 inhibitor HC-030031. In addition, KB significantly decreased the scratching bouts of ACD mice, reduced the skin lesion scores, mast cells degranulation, and epidermal thickening, inhibited the production of inflammatory chemokines/cytokines and CGRP, and down-regulated the levels of p-ERK1/2, p-p38, and p-STAT3, compared to the ACD mice. Moreover, continuous application of KB induced the desensitization of TRPA1 channels. Also, KB inhibited the expression of p-ERK1/2, p-p38, and p-STAT3, and down-regulated the expression of inflammatory chemokines and cytokines in vitro, which were reversed by the TRPA1 siRNA.

CONCLUSIONS

KB alleviated the pruritus and skin inflammation in ACD mice through TRPA1 channels desensitization and down-regulation of intracellular MAPK and JAK/STAT3 signaling pathways. Our results suggested that Ke-teng-zi is a potential drug for the treatment of inflammatory skin diseases such as ACD.

Two Phase 3 Trials of Lebrikizumab for Moderate-to-Severe Atopic Dermatitis

BACKGROUND

Lebrikizumab, a high-affinity IgG4 monoclonal antibody targeting interleukin-13, prevents the formation of the interleukin-4Rα-interleukin-13Rα1 heterodimer receptor signaling complex.

METHODS

We conducted two identically designed, 52-week, randomized, double-blind, placebo-controlled, phase 3 trials; both trials included a 16-week induction period and a 36-week maintenance period. Eligible patients with moderate-to-severe atopic dermatitis (adults [≥18 years of age] and adolescents [12 to <18 years of age, weighing ≥40 kg]) were randomly assigned in a 2:1 ratio to receive either lebrikizumab at a dose of 250 mg (loading dose of 500 mg at baseline and week 2) or placebo, administered subcutaneously every 2 weeks. Outcomes for the induction period were assessed up to 16 weeks and are included in this report. The primary outcome was an Investigator's Global Assessment (IGA) score of 0 or 1 (indicating clear or almost clear skin; range, 0 to 4 [severe disease]) with a reduction (indicating improvement) of at least 2 points from baseline at week 16. Secondary outcomes included a 75% improvement in the Eczema Area and Severity Index score (EASI-75 response) and assessments of itch and of itch interference with sleep. Safety was also assessed.

RESULTS

In trial 1, the primary outcome was met in 43.1% of 283 patients in the lebrikizumab group and in 12.7% of 141 patients in the placebo group (P<0.001); an EASI-75 response occurred in 58.8% and 16.2%, respectively (P<0.001). In trial 2, the primary outcome was met in 33.2% of 281 patients in the lebrikizumab group and in 10.8% of 146 patients in the placebo group (P<0.001); an EASI-75 response occurred in 52.1% and 18.1%, respectively (P<0.001). Measures of itch and itch interference with sleep indicated improvement with lebrikizumab therapy. The incidence of conjunctivitis was higher among patients who received lebrikizumab than among those who received placebo. Most adverse events during the induction period were mild or moderate in severity and did not lead to trial discontinuation.

CONCLUSIONS

In the induction period of two phase 3 trials, 16 weeks of treatment with lebrikizumab was effective in adolescents and adults with moderate-to-severe atopic dermatitis. (Funded by Dermira; ADvocate1 and ADvocate2 ClinicalTrials.gov numbers, NCT04146363 and NCT04178967, respectively.).

Epicutaneous Sensitization and Food Allergy: Preventive Strategies Targeting Skin Barrier Repair-Facts and Challenges

Food allergy represents a growing public health and socio-economic problem with an increasing prevalence over the last two decades. Despite its substantial impact on the quality of life, current treatment options for food allergy are limited to strict allergen avoidance and emergency management, creating an urgent need for effective preventive strategies. Advances in the understanding of the food allergy pathogenesis allow to develop more precise approaches targeting specific pathophysiological pathways. Recently, the skin has become an important target for food allergy prevention strategies, as it has been hypothesized that allergen exposure through the impaired skin barrier might induce an immune response resulting in subsequent development of food allergy. This review aims to discuss current evidence supporting this complex interplay between the skin barrier dysfunction and food allergy by highlighting the crucial role of epicutaneous sensitization in the causality pathway leading to food allergen sensitization and progression to clinical food allergy. We also summarize recently studied prophylactic and therapeutic interventions targeting the skin barrier repair as an emerging food allergy prevention strategy and discuss current evidence controversies and future challenges. Further studies are needed before these promising strategies can be routinely implemented as prevention advice for the general population.

Targeting Interleukin 13 for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a common chronic inflammatory skin condition that has a significant impact on a patient's quality of life and requires ongoing management. Conventional topical and systemic therapies do not target specific components of AD pathogenesis and, therefore, have limited efficacy and may be associated with long-term toxicity. Thus, AD management is challenging, with a significant proportion of patients not achieving clear skin or a reduction in pruritus. There remains a large unmet need for effective therapeutic strategies with favorable safety profiles that can be used long-term in patients with refractory AD. The emergence of targeted biological and small molecule therapies has effectively broadened available treatment options for moderate-to-severe AD. Most recently, interleukin 13 (IL-13) inhibitors were shown to be efficacious and well-tolerated, with tralokinumab already approved for use in this patient population. It is important for dermatologists to be aware of the evidence behind this emerging class of biologic agents to guide treatment choices and improve outcomes in patients with AD. The main objective of this paper is to review the current literature regarding the efficacy and safety of current and emerging anti-IL-13 monoclonal antibodies, including tralokinumab, lebrikizumab, cendakimab, and eblasakimab, for the treatment of moderate-to-severe AD.

Efficacy and Safety of Lebrikizumab in Combination With Topical Corticosteroids in Adolescents and Adults With Moderate-to-Severe Atopic Dermatitis: A Randomized Clinical Trial (ADhere)

Importance

Lebrikizumab (LEB), a high-affinity monoclonal antibody targeting interleukin (IL)-13, demonstrated efficacy and safety in patients with moderate-to-severe atopic dermatitis (AD) during 16 weeks of monotherapy in a phase 2b trial, and two 52-week phase 3 trials.

Objective

To evaluate efficacy and safety of LEB combined with low- to mid-potency topical corticosteroids (TCS) in patients with moderate-to-severe AD.

Design, Setting, and Participants

The ADhere trial was a 16-week randomized, double-blinded, placebo (PBO)-controlled, multicenter, phase 3 clinical trial conducted from February 3, 2020, to September 16, 2021. The study was conducted at 54 outpatient sites across Germany, Poland, Canada, and the US and included adolescent (aged ≥12 to <18 years weighing ≥40 kg) and adult patients with moderate-to-severe AD. The treatment allocation ratio was 2:1 (LEB:PBO).

Interventions

Overall, 211 patients were randomized to subcutaneous LEB (loading dose of 500 mg at baseline and week 2, followed by 250 mg every 2 weeks [Q2W] thereafter) or PBO Q2W in combination with TCS for 16 weeks.

Main Outcomes and Measures

Efficacy analyses at week 16 included proportions of patients achieving Investigator's Global Assessment score of 0 or 1 (IGA [0,1]) with 2 or more points improvement from baseline, and 75% improvement in the Eczema Area and Severity Index (EASI-75). Key secondary end points included evaluation of itch, itch interference on sleep, and quality of life. Safety assessments included monitoring adverse events (AEs).

Results

The mean (SD) age of patients was 37.2 (19.3) years, 103 (48.8%) patients were women, 31 (14.7%) patients were Asian, and 28 (13.3%) patients were Black/African American. At week 16, IGA (0,1) was achieved by 145 (41.2%) patients in the LEB+TCS group vs 66 (22.1%) receiving PBO+TCS (P = .01); corresponding proportions of patients achieving EASI-75 were 69.5% vs 42.2% (P < .001). The LEB+TCS group showed statistically significant improvements in all key secondary end points. Most treatment-emergent adverse events (TEAEs) were nonserious, mild or moderate in severity, and did not lead to study discontinuation. The TEAEs frequently reported in the LEB+TCS group included conjunctivitis (7 [4.8%]), headache (7 [4.8%]), hypertension (4 [2.8%]), injection site reactions (4 [2.8%]), and herpes infection (5 [3.4%]) vs 1.5% or less patient-reported frequencies in the PBO+TCS group. Similar frequencies of patient-reported serious AEs following LEB+TCS (n = 2, 1.4%) and PBO+TCS (n = 1, 1.5%).

Conclusions and Relevance

In this randomized phase 3 clinical trial, LEB+TCS was associated with improved outcomes in adolescents and adults with moderate-to-severe AD compared with TCS alone, and safety was consistent with previously reported AD trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT04250337.

IL-13, periostin and dipeptidyl-peptidase-4 reveal endotype-phenotype associations in atopic dermatitis

BACKGROUND

The heterogeneous (endo)phenotypes of atopic dermatitis (AD) require precision medicine. Currently, systemic therapy is recommended to patients with an Eczema Area and Severity Index (EASI)≥16. Previous studies have demonstrated an improved treatment response to the anti-interleukin (IL)-13 antibody tralokinumab in AD subgroups with elevated levels of the IL-13-related biomarkers dipeptidyl-peptidase (DPP)-4 and periostin.

METHODS

Herein, 373 AD patients aged≥12 years were stratified by IL-13high , periostinhigh and DPP-4high endotypes using cross-sectional data from the ProRaD cohort Bonn. "High" was defined as >80th quantile of 47 non-atopic controls. We analyzed endotype-phenotype associations using machine-learning gradient boosting compared to logistic regression.

RESULTS

AD severity and eosinophils correlated with IL-13 and periostin levels. Correlations of IL-13 with EASI were stronger in patients with increased (rs=0.482) than with normal (rs=0.342) periostin levels. We identified eosinophilia>6% and an EASI range of 5.5-17 dependent on the biomarker combination to be associated with increasing probabilities of biomarkerhigh endotypes. Also patients with mild-to-low-moderate severity (EASI<16) featured increased biomarkers (IL-13high : 41%, periostinhigh : 48.4%, DPP-4high : 22.3%). Herthoge sign (adjusted Odds Ratio (aOR)=1.89, 95% Confidence Interval (CI) [1.14-3.14]) and maternal allergic rhinitis (aOR=2.79-4.47) increased the probability of an IL-13high -endotype, "dirty neck" (aOR=2.83 [1.32-6.07]), orbital darkening (aOR=2.43 [1.08-5.50]), keratosis pilaris (aOR=2.21 [1.1-4.42]) and perleche (aOR=3.44 [1.72-6.86]) of a DPP-4high -endotype.

CONCLUSIONS

A substantial proportion of patients with EASI<16 featured high biomarker levels suggesting systemic impact of skin inflammation already below the current cut-off for systemic therapy. Our findings facilitate the identification of patients with distinct endotypes potentially linked to response to IL-13-targeted therapy.

Combined application of dupilumab and mite allergen-specific immunotherapy in children with moderate to severe atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic, relapsing inflammatory skin disease that manifests in skin dryness, severe itching, and eczema, and can significantly impact a patient's quality of life. Current treatment regimens do not prevent the recurrence of the disease and are associated with adverse effects. Here, we report two cases of moderate-to-severe AD in children that were treated with dupilumab, a dual inhibitor of IL-4 and IL-13 signaling, in combination with mite allergen-specific immunotherapy.

CASE SUMMARY

Both patients presented with the diagnosis of AD that was not adequately controlled by the conventional treatment regimen, including topical corticosteroids (TCS), topical calcineurin inhibitors, emollients, and the traditional Chinese medicine treatments. In both patients, AD-associated skin irritation impacted the quality of life, disturbed sleep patterns, and caused stress and anxiety.Patients received treatment with dupilumab and mite allergen-specific immunotherapy in addition to the baseline treatment regimen of external glucocorticoids (TCS) and oral antihistamines. Nine months after beginning of treatment, clinical symptoms, signs, medication scores, and evaluation scale scores of both children significantly improved, and the treatment was associated with an overall good tolerance.

CONCLUSION

A combination of dupilumab and mite allergen-specific immunotherapy in addition to the standard anti-AD treatment improves clinical symptoms and is not associated with increased incidence of adverse effects.

Immunotherapy in atopic dermatitis

In the past decade, the emergence of biologics targeting human cytokine networks has advanced a new era in atopic dermatitis therapy. Dupilumab, in particular, the most widely studied and used IL-4/IL-13 inhibitor, has been considered a milestone in the treatment of patients with moderate-to-severe atopic dermatitis. In addition to the IL-4 and IL-13 pathways, many other cytokines and receptors have been newly targeted as therapeutic options. In this review, the authors provide an overview of the approved and tested biologics and JAK inhibitors for the treatment of atopic dermatitis, including their advantages and limitations.

Evaluation of the Anti-Atopic Dermatitis Effects of α-Boswellic Acid on Tnf-α/Ifn-γ-Stimulated HaCat Cells and DNCB-Induced BALB/c Mice

Boswellic acids, triterpenoids derived from the genus Boswellia (Burseraceae), are known for their anti-inflammatory and anti-tumor efficacy. Atopic dermatitis is a chronic, non-infectious inflammatory skin disease. However, the effects of α-boswellic acid on atopic dermatitis have not been studied. Therefore, in this study we examined the expression level of pro-inflammatory cytokines, histopathological analysis, and physiological data from BALB/c mice with atopic-like dermatitis induced by 2,4-dinitrochlorobenzene and TNF-α/IFN-γ-stimulated HaCaT cells to better understand the agent’s anti-atopic dermatitis efficacy. First, we found that α-boswellic reduced the epidermal thickening, mast cell numbers, and dermal infiltration of 2,4-dinitrochlorobenzene-induced atopic-like dermatitis in BALB/c mice. Furthermore, we also found that α-boswellic acid can restore transepidermal water loss and skin reddening in mice. In human keratinocytes inflamed by TNF-α/IFN-γ, α-boswellic acid inhibited MAP kinase activation and showed a reduction in NF-κB nuclear translocation. Finally, α-boswellic acid can reduce the expression level of cytokines (IL-1β, IL-6, and IL-8) following the stimulation of TNF-α/IFN-γ in HaCaT cells. Taken together, our study suggests that α-boswellic acids are a potential component for the development of anti-atopic dermatitis drugs.

IL-1 Family Cytokines in Inflammatory Dermatoses: Pathogenetic Role and Potential Therapeutic Implications

The interleukin-1 (IL-1) family is involved in the correct functioning and regulation of the innate immune system, linking innate and adaptative immune responses. This complex family is composed by several cytokines, receptors, and co-receptors, all working in a balanced way to maintain homeostasis. Dysregulation of these processes results in tissue inflammation and is involved in the pathogenesis of common inflammatory dermatoses such as psoriasis, hidradenitis suppurativa, and atopic dermatitis. Therefore, therapeutic targeting of IL-1 pathways has been studied, and several monoclonal antibodies are currently being assessed in clinical trials. So far, promising results have been obtained with anti-IL-36R spesolimab and imsidolimab in pustular psoriasis, and their efficacy is being tested in other conditions.

Atopic Dermatitis: Striving for Reliable Biomarkers

Atopic dermatitis (AD) is a highly heterogeneous inflammatory disease regarding both its pathophysiology and clinical manifestations. However, it is treated according to the “one-size-fits-all” approach, which may restrict response to treatment. Thus, there is an unmet need for the stratification of patients with AD into distinct endotypes and clinical phenotypes based on biomarkers that will contribute to the development of precision medicine in AD. The development of reliable biomarkers that may distinguish which patients with AD are most likely to benefit from specific targeted therapies is a complex procedure and to date none of the identified candidate biomarkers for AD has been validated for use in routine clinical practice. Reliable biomarkers in AD are expected to improve diagnosis, evaluate disease severity, predict the course of disease, the development of comorbidities, or the therapeutic response, resulting in effective and personalized treatment of AD. Among the studied AD potential biomarkers, thymus and activation-regulated chemokine/C-C motif ligand 17 (TARC/CCL17) has the greatest evidence-based support for becoming a reliable biomarker in AD correlated with disease severity in both children and adults. In this review, we present the most prominent candidate biomarkers in AD and their suggested use.

Dupilumab combined with low-dose systemic steroid therapy improves efficacy and safety for bullous pemphigoid

BACKGROUND

Routine systemic therapy for bullous pemphigoid (BP) has been challenged due to the inevitably adverse effects. According to the successful applications of dupilumab in BP cases reported, therefore, we investigate the real-life efficacy and safety of dupilumab combined with low-dose oral steroid for BP.

RESEARCH DESIGN AND METHODS

A cohort of BP patients who received either dupilumab plus low-dose methylprednisolone (dupilumab group) or merely methylprednisolone (control group) was retrospectively reviewed. The time to disease control was investigated. Additionally, the control dose and cumulative dosage of steroids, Bullous Pemphigoid Disease Area Index(BPDAI) scores, pruritus scores, and adverse events were assessed.

RESULTS

A total of 40 patients, with 20 in each group, were retrospectively studied. The time to disease control was shorter in the dupilumab group than the control group (14 days vs. 19 days, p=0.043). When the disease was controlled, the control dose and cumulative dosage of methylprednisolone in the dupilumab group were substantially lower than those of the control (24.6mg vs. 48.8mg, 376.8mg vs. 985.6mg, both p<0.01). Compared with the control, the percentage change from baseline in BPDAI scores and pruritus scores were both significantly reduced, and the adverse events were also less frequent in the dupilumab group.

CONCLUSIONS

The combination therapy of dupilumab plus low-dose methylprednisolone exhibits superior efficacy and safety in comparison with the current first-line systemic therapy for BP. This article is protected by copyright. All rights reserved.

Use of Dupilumab in Bullous Pemphigoid: Where Are We Now?

Bullous pemphigoid (BP) is the most frequent autoimmune subepidermal bullous disease. At present, the main treatment options are represented by corticosteroids and immunosuppressant drugs. Steroids often need to be administered in high doses, with subsequent adverse events and safety issues, as BP mainly affects elderly people. As dupilumab, a recombinant fully human IgG4 monoclonal antibody with binding specificity to human interleukin-4 receptor IL-4Rα has become paramount in the treatment of atopic dermatitis, its use in autoimmune bullous diseases has been theorized and it has been used to treat patients with BP. Dupilumab seems to be an effective and safe option to treat recalcitrant BP. Here, we report the results of a literature review on the use of dupilumab in BP, including a total of 30 treated patients in 9 papers.

Old drugs, new tricks: Emerging role of drug repurposing in the management of atopic dermatitis

Atopic dermatitis is a chronic recurring pruritic inflammatory skin disease manifested by increased pro-inflammatory mediators which lead to dry, thickened, cracked, scaly skin. The current treatment options for atopic dermatitis management comprise drawbacks and leave unmet effective clinical needs. So, the approach for repurposing existing drugs for atopic dermatitis management may potentially overcome these unmet needs. Diseases that share the common pathophysiological pathways with atopic dermatitis can serve as a foundation for the repurposing of drugs. Drugs used in the management of cancer, rheumatoid arthritis, and other immune-mediated diseases such as psoriasis are under investigation to know the potential in atopic dermatitis management by utilizing repurposing strategies for a novel therapeutic indication. This review mainly envisages the probable repurposing of drugs for the management of atopic dermatitis disease; the barriers and regulatory aspects involved in the repurposing of existing drugs.

From Skin Barrier Dysfunction to Systemic Impact of Atopic Dermatitis: Implications for a Precision Approach in Dermocosmetics and Medicine

: Atopic dermatitis (AD) affects up to 20% of children and is considered the starting point of the atopic march with the development of food allergy, asthma, and allergic rhinitis. The heterogeneous phenotype reflects distinct and/or overlapping pathogenetic mechanisms with varying degrees of epidermal barrier disruption, activation of different T cell subsets and dysbiosis of the skin microbiome. Here, we review current evidence suggesting a systemic impact of the cutaneous inflammation in AD together with a higher risk of asthma and other comorbidities, especially in severe and persistent AD. Thus, early therapy of AD to restore the impaired skin barrier, modified microbiome, and target type 2 inflammation, depending on the (endo)phenotype, in a tailored approach is crucial. We discuss what we can learn from the comorbidities and the implications for preventive and therapeutic interventions from precision dermocosmetics to precision medicine. The stratification of AD patients into biomarker-based endotypes for a precision medicine approach offers opportunities for better long-term control of AD with the potential to reduce the systemic impact of a chronic skin inflammation and even prevent or modify the course, not only of AD, but possibly also the comorbidities, depending on the patient’s age and disease stage.

Current and Emerging Strategies to Inhibit Type 2 Inflammation in Atopic Dermatitis

Type 2 immunity evolved to combat helminth infections by orchestrating a combined protective response of innate and adaptive immune cells and promotion of parasitic worm destruction or expulsion, wound repair, and barrier function. Aberrant type 2 immune responses are associated with allergic conditions characterized by chronic tissue inflammation, including atopic dermatitis (AD) and asthma. Signature cytokines of type 2 immunity include interleukin (IL)-4, IL-5, IL-9, IL-13, and IL-31, mainly secreted from immune cells, as well as IL-25, IL-33, and thymic stromal lymphopoietin, mainly secreted from tissue cells, particularly epithelial cells. IL-4 and IL-13 are key players mediating the prototypical type 2 response; IL-4 initiates and promotes differentiation and proliferation of naïve T-helper (Th) cells toward a Th2 cell phenotype, whereas IL-13 has a pleiotropic effect on type 2 inflammation, including, together with IL-4, decreased barrier function. Both cytokines are implicated in B-cell isotype class switching to generate immunoglobulin E, tissue fibrosis, and pruritus. IL-5, a key regulator of eosinophils, is responsible for eosinophil growth, differentiation, survival, and mobilization. In AD, IL-4, IL-13, and IL-31 are associated with sensory nerve sensitization and itch, leading to scratching that further exacerbates inflammation and barrier dysfunction. Various strategies have emerged to suppress type 2 inflammation, including biologics targeting cytokines or their receptors, and Janus kinase inhibitors that block intracellular cytokine signaling pathways. Here we review type 2 inflammation, its role in inflammatory diseases, and current and future therapies targeting type 2 pathways, with a focus on AD.

A Review of the Immunologic Pathways Involved in Bullous Pemphigoid and Novel Therapeutic Targets

Bullous pemphigoid (BP) is a rare, chronic antibody-mediated autoimmune blistering disease primarily affecting the elderly, with an age of onset over 60. Current treatment options are limited and involve the use of corticosteroids and immunosuppressants, but their long-term use is associated with significant morbidity and mortality. In Japan, human intravenous immunoglobin is approved for the treatment of corticosteroid-refractory BP. However, no treatment option is approved by the Food and Drug Administration for the management of BP. Therefore, developing effective therapies free of debilitating side effects is imperative. In this review, we summarize the main immunologic pathways involved in the pathogenesis of BP, with an emphasis on the role of eosinophils, immunoglobulins, cytokines such as the interleukin (IL)-4 and IL-5, and complements. We further discuss the latest advances with novel therapeutic targets tested for the management of BP. Ongoing efforts are needed to run well-designed controlled trials and test the efficacy and safety of investigational drugs while providing much-needed access to these medications for refractory patients who will not otherwise be able to afford them as off-label prescriptions.

Atopic dermatitis: pathomechanisms and lessons learned from novel systemic therapeutic options

Atopic dermatitis (AD) is a chronic, heterogenous, inflammatory skin disorder associated with a high skin-related health burden, typically starting in childhood and often persisting into adulthood. AD is characterized by a wide range of clinical phenotypes, reflecting multiple underlying pathophysiological mechanisms and interactions between genetics, immune system dysregulation, and environmental factors. In this review, we describe the diverse cellular and molecular mechanisms involved in AD, including the critical role of T cell-driven inflammation, primarily via T helper (Th) 2- and Th17-derived cytokines, many of which are mediated by the Janus kinase (JAK) signaling pathway. These local inflammatory processes interact with sensory neuronal pathways, contributing to the clinical manifestations of AD, including itch, pain, and sleep disturbance. The recent elucidation of the molecular pathways involved in AD has allowed treatment strategies to evolve from broad-acting systemic immunosuppressive therapies to more targeted agents, including JAK inhibitors and cytokine-specific biologic agents. Evidence from the clinical development of these targeted therapies has reinforced and expanded our understanding of the pathophysiological mechanisms underlying AD and holds promise for individualized treatment strategies tailored to specific AD subtypes.

Immune Tolerance vs. Immune Resistance: The Interaction Between Host and Pathogens in Infectious Diseases

The immune system is most likely developed to reduce the harmful impact of infections on the host homeostasis. This defense approach is based on the coordinated activity of innate and adaptive immune system components, which detect and target infections for containment, killing, or expulsion by the body's defense mechanisms. These immunological processes are responsible for decreasing the pathogen burden of an infected host to maintain homeostasis that is considered to be infection resistance. Immune-driven resistance to infection is connected with a second, and probably more important, defensive mechanism: it helps to minimize the amount of dysfunction imposed on host parenchymal tissues during infection without having a direct adverse effect on pathogens. Disease tolerance is a defensive approach that relies on tissue damage control systems to prevent infections from causing harm to the host. It also uncouples immune-driven resistance mechanisms from immunopathology and disease, allowing the body to fight infection more effectively. This review discussed the cellular and molecular processes that build disease tolerance to infection and the implications of innate immunity on those systems. In addition, we discuss how symbiotic relationships with microbes and their control by particular components of innate and adaptive immunity alter disease tolerance to infection.

Neuro-immune communication regulating pruritus in atopic dermatitis

Atopic dermatitis (AD) is a common, chronic-relapsing inflammatory skin disease with significant disease burden. Genetic and environmental trigger factors contribute to AD, activating two of our largest organs, the nervous and immune system. Dysregulation of neuro-immune circuits plays a key role in the pathophysiology of AD causing inflammation, pruritus, pain, and barrier dysfunction. Sensory nerves can be activated by environmental or endogenous trigger factors transmitting itch stimuli to the brain. Upon stimulation, sensory nerve endings also release neuromediators into the skin contributing again to inflammation, barrier dysfunction and itch. Additionally, dysfunctional peripheral and central neuronal structures contribute to neuroinflammation, sensitization, nerve elongation, neuropathic itch, thus chronification and therapy-resistance. Consequently, neuro-immune circuits in skin and central nervous system may be targets to treat pruritus in AD. Cytokines, chemokines, proteases, lipids, opioids, ions excite/sensitize sensory nerve endings not only induce itch but further aggravate/perpetuate inflammation, skin barrier disruption, and pruritus. Thus, targeted therapies for neuro-immune circuits as well as pathway inhibitors (e.g., kinase inhibitors) may be beneficial to control pruritus in AD either in systemic and/or topical form. Understanding neuro-immune circuits and neuronal signaling will optimize our approach to control all pathological mechanisms in AD, inflammation, barrier dysfunction and pruritus.

The emerging role of the neuroimmune cytokine interleukin-31 in chronic inflammatory skin diseases

Chronic inflammatory skin diseases pose significant challenges for both patients and clinicians worldwide. Atopic dermatitis (AD), the most common of these diseases, affects up to 8% of the adult population depending on geographic location and demographic group, while prurigo nodularis (PN) is a less common disease that causes significant burden. In these inflammatory skin conditions, pruritus is a cardinal symptom. Interleukin 31 (IL-31), described as a neuroimmune modulator, has been shown to have a prominent role in both inflammation and itch. IL-31 acts through a receptor complex consisting of IL-31 receptor α (IL-31RA) and oncostatin M receptor β (OSMRβ). IL-31 is produced by a variety of cells, including type 2 helper T cells, and IL-31 signaling can activate three important pathways: JAK/STAT, P13K/AKT, and ERK/MAPK. IL-31 is elevated in AD and PN, and is thought to induce chemokine genes CCL1, CCL17, and CCL22. The chemokines recruit T cells to affected skin, where more IL-31 is secreted. The IL-31 receptor complex is also abundant in dorsal root ganglia in human tissue, home of primary sensory neurons and the distal source of "itch sensations". IL-31 and its receptor complex have an important role in chronic inflammatory diseases, including AD and PN, and blocking the IL-31/IL-31RA signaling may represent an important new therapeutic approach for these diseases, which continue to have significant unmet medical needs.

Mechanistic Insights into the Anti-Pruritic Effects of Lebrikizumab, an Anti-IL-13 Monoclonal Antibody

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory skin disease with persistent and severe itch among its hallmark features. Significant increases in type 2 cytokines (i.e., IL-4, IL-13, IL-31) have been documented in acute AD lesions and lead to multi-faceted downstream effects, including inflammation, epidermal barrier dysfunction, and itch.

OBJECTIVE

The primary objective of preclinical studies reported here was to test direct effects of IL-13 and the anti-IL-13 monoclonal antibody, lebrikizumab, in a human dorsal root ganglion (hDRG) model in itch amplification, neuronal excitability, and transcriptional downstream targets.

METHODS

Neuroactive effects were assessed via live cell calcium imaging, electric field stimulation, and RNA sequencing of hDRGs stimulated with IL-13 alone or in combination with lebrikizumab.

RESULTS

These preclinical findings suggest that IL-13 has a direct enhancer role in multiple itch and neuroactive pathways, as well as transcriptional downstream effects, and provide key insights into the mechanistic basis for lebrikizumab's anti-itch effects.

CONCLUSION

IL-13 is a potent enhancer of neuronal responses to different itch stimuli, consistent with the neuro-immune axis contributing to chronic itch-associated inflammatory skin disease, and that blockade of this cytokine pathway may provide a therapeutic approach.

Bee Venom Within Liposomes Synergistically Inhibit Atopic Dermatitis in Mice

Background: This study was performed to determine the effects of liposome-encapsulated bee venom (BV) treatment of inflammatory factors in atopic dermatitis (AD) compared with BV treatment.Methods: AD was induced by phthalic anhydride in mice and the effects of BV liposomes were measured. Using Leica Application Suite, thickened epidermis and dermis were measured after BV liposome treatment (0.05 and 0.1 μg/mL). The number of stained mast cells and the concentration of immunoglobulin (Ig)E were measured. Serum IgE concentration was analyzed using an enzyme-linked immunosorbent assay. The serum concentrations of interleukin (IL)-1, IL-4, and IL-6 inflammatory cytokines were measured. The levels of messenger ribonucleic acid expression of proinflammatory cytokines and chemokines were measured using reverse transcription polymerase chain reaction. Inhibition of mitogen-activated protein kinase activation, was analyzed on western blot. To measure the transcriptional activity (NF-κB inhibition by BV liposomes), western blots (p65, p-IκB, p50, and IκB) were also performed.Results: The weight of lymph nodes, serum IgE concentrations, morphological changes in the skins from the backs of the mice, and mast cell numbers in inflamed tissues were noticeably lower in the BV liposome treatment group compared with the BV treatment group. The concentrations of pro-inflammatory cytokines (IL-1, IL-4, IL-6) and chemokines (TSLP, CCL22) were also reduced. Activation of mitogen-activated protein kinase (p-ERK and p-p38), and transcriptional activity (p65, p-IκB, p50, and IκB) was strongly suppressed in the BV liposome group.Conclusion: BV liposomes may have a better therapeutic effect than BV for the treatment of AD.

IL-13 Genetic Susceptibility to Bullous Pemphigoid: A Potential Target for Treatment and a Prognostic Marker

Background

Bullous pemphigoid (BP) is a senile chronic autoimmune bullous skin disease with a high relapse rate, which significantly impairs patients’ quality of life and contributes to disease mortality. This observational case-control study explores the gene polymorphisms of cytokines and their clinical significance in Chinese patients with BP.

Methods

IL-1α (rs1800587), IL-1β (rs16944, rs1143627, rs1143634), IL-4 (rs2243250), IL-6 (rs1800795), IL-10 (rs1800896, rs1800871, rs1800872), IL-13 (rs1800925, rs20541), TNF-α (rs1799964, rs1800630, rs1799724, rs361525), IFN-γ (rs1799964, rs1800630, rs361525, rs1800629, rs4248160, rs1800750), and TGF-β1 (rs2317130, rs1800469, rs4803457) genes were genotyped in the healthy controls and BP patients, respectively. Expression of these cytokines in serum was measured. Medical profiles of patients, including baseline characteristics and prognosis, were statistically analyzed.

Results

We found that IL-1 β and IL-13 concentrations were higher in the BP patients’ sera compared to those in the controls. For IL-13, significant differences were found in the nucleotide ratio/genotype/haploid frequency/haplotype, respectively. IL-13 (rs20541, rs1800925) is related to gender, and the IL-13 genotype was significantly associated with recurrence.

Conclusions

BP is associated with IL-13 gene polymorphism and IL-13 concentration is elevated in blood circulation in patients with BP. Our results support that IL-13 is relevant in the pathogenesis of BP, suggesting that IL-13 could potentially represent a promising target for BP therapy and a prognostic marker.

The Epidermis: Redox Governor of Health and Diseases

A functional epithelial barrier necessitates protection against dehydration, and ichthyoses are caused by defects in maintaining the permeability barrier in the stratum corneum (SC), the uppermost protective layer composed of dead cells and secretory materials from the living layer stratum granulosum (SG). We have found that loricrin (LOR) is an essential effector of cornification that occurs in the uppermost layer of SG (SG1). LOR promotes the maturation of corneocytes and extracellular adhesion structure through organizing disulfide cross-linkages, albeit being dispensable for the SC permeability barrier. This review takes psoriasis and AD as the prototype of impaired cornification. Despite exhibiting immunological traits that oppose each other, both conditions share the epidermal differentiation complex as a susceptible locus. We also review recent mechanistic insights on skin diseases, focusing on the Kelch-like erythroid cell-derived protein with the cap "n" collar homology-associated protein 1/NFE2-related factor 2 signaling pathway, as they coordinate the epidermis-intrinsic xenobiotic metabolism. Finally, we refine the theoretical framework of thiol-mediated crosstalk between keratinocytes and leukocytes in the epidermis that was put forward earlier.

Emerging topical drug delivery approaches for the treatment of Atopic dermatitis

BACKGROUND

Atopic dermatitis is a chronic, relapsing skin inflammation disease that generally affects 20% of children and 1-3% of adults. It is characterized by pruritus, inflammatory skin lesions, and skin barrier defect. The pillar treatment is topical therapies that have shown great adherence and incredible results in alleviating symptoms of atopic dermatitis. Topical corticosteroids and calcineurin inhibitors have shown improvement in the symptoms of atopic dermatitis but have certain side effects. There is need to develop new therapies or novel drug delivery approaches which can overcome drawbacks of the conventional formulation and increase the therapeutic efficacy.

AIM

The scope of this review is to describe the new topical therapies including phosphodiesterase inhibitors, Janus kinase inhibitors, and nano-formulations such as nanoemulsion, polymeric and lipid nanoparticles, vesicular system, and micelles.

METHODS

The article reviews and discusses the published literature of the topical drug delivery approaches for treatment of Atopic dermatitis.

RESULTS

The reported literature highlighted the benefits of novel topical formulations exhibiting targeted drug delivery, better penetration, enhanced therapeutic efficacy, and overcome systemic side effects.

CONCLUSION

Literature indicated that the new therapies and novel drug delivery approaches found to be the therapeutically more effective in increasing the efficacy of drugs and reducing the side effects in comparison with the conventional treatments for Atopic dermatitis. This has provided a way to modify and develop more such formulations for dermal delivery.

The Pathology of Type 2 Inflammation-Associated Itch in Atopic Dermatitis

Accumulated evidence on type 2 inflammation-associated itch in atopic dermatitis has recently been reported. Crosstalk between the immune and nervous systems (neuroimmune interactions) is prominent in atopic dermatitis research, particularly regarding itch and inflammation. A comprehensive understanding of bidirectional neuroimmune interactions will provide insights into the pathogenesis of itch and its treatment. There is currently no agreed cure for itch in atopic dermatitis; however, increasing numbers of novel and targeted biologic agents have potential for its management and are in the advanced stages of clinical trials. In this review, we summarize and discuss advances in our understanding of type 2 inflammation-associated itch and implications for its management and treatment in patients with atopic dermatitis.

Interleukin-31: The "itchy" cytokine in inflammation and therapy

The cytokine interleukin-31 has been implicated in the pathophysiology of multiple atopic disorders such as atopic dermatitis (AD), allergic rhinitis, and airway hyper-reactivity. In AD, IL-31 has been identified as one of the main "drivers" of its cardinal symptom, pruritus. Here, we summarize the mechanisms by which IL-31 modulates inflammatory and allergic diseases. T_H 2 cells play a central role in AD and release high levels of T_H 2-associated cytokines including IL-31, thereby mediating inflammatory responses, initiating immunoregulatory circuits, stimulating itch, and neuronal outgrowth through activation of the heterodimeric receptor IL-31 receptor A (IL31RA)/Oncostatin M receptor (OSMRβ). IL31RA expression is found on human and murine dorsal root ganglia neurons, epithelial cells including keratinocytes and various innate immune cells. IL-31 is a critical cytokine involved in neuroimmune communication, which opens new avenues for cytokine modulation in neuroinflammatory diseases including AD/pruritus, as validated by recent clinical trials using an anti-IL-31 antibody. Accordingly, inhibition of IL-31-downstream signaling may be a beneficial approach for various inflammatory diseases including prurigo. However, as to whether downstream JAK inhibitors directly block IL-31-mediated-signaling needs to be clarified. Targeting the IL-31/IL31RA/OSMRβ axis appears to be a promising approach for inflammatory, neuroinflammatory, and pruritic disorders in the future.

Tralokinumab for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a relapsing or chronic heterogeneous inflammatory skin disorder with a substantial economic and social impact. AD is a multifactorial disease regulated by a diverse set of environmental and genetic determinants. The main factors involved in the pathogenesis of AD are epidermal barrier dysfunction, immune dysregulation, and dysbiosis. Current data have valued interleukin (IL)-13 as conceivably the crucial cytokine in the underlying inflammation of AD. Advances in understanding AD pathophysiology have driven the progress of targeted immunomodulatory treatments for the treatment of AD, including tralokinumab, a selective IL-13 inhibitor. A phase IIb clinical trial showed that a dosing regimen of 150 or 300 mg every 2 weeks effectively treated moderate-to-severe AD in adults with an acceptable tolerability profile. Phase III clinical trials demonstrated that results with tralokinumab in monotherapy were superior to those with placebo at 16 weeks of treatment. It was also well tolerated up to 52 weeks in the vast majority of patients. In addition, in association with topical corticosteroids, tralokinumab was well tolerated and effective and had a favorable risk-benefit profile. These data provide additional evidence that IL-13 is central to AD pathogenesis, suggesting that tralokinumab may be seen as an innovative option for the treatment of moderate-to-severe AD.

Efficacy and Safety of Janus Kinase Inhibitors for the Treatment of Atopic Dermatitis: A Systematic Review and Meta-Analysis

Background

Current therapeutic options for atopic dermatitis (AD) are limited. Janus kinase (JAK) inhibitors may be viable alternatives.

Objectives

To assess the efficacy and safety of JAK inhibitors for AD treatment.

Methods

We searched PubMed, Embase, the Cochrane Controlled Register of Trials, Web of Science, Global Resource of Eczema Trials database, and ClinicalTrials.gov from inception to September 1, 2020. Randomized clinical trials (RCTs) comparing JAK inhibitors with placebo/vehicle treatment for AD patients were included. The primary study outcomes included (1) the change (%) from the Eczema Area and Severity Index (EASI) baseline expressed as weighted mean difference (WMD) and 95% confidence interval (95% CI), and (2) the Investigator's Global Assessment (IGA) response and safety outcomes expressed as relative risk (RR) and 95% CI.

Results

We included 14 RCTs published in 13 studies (3,822 patients). Treatment with JAK inhibitors significantly improved IGA response (RR 2.83, 95% CI 2.25–3.56, p < 0.001) and EASI score (WMD −28.82, 95% CI −34.48 to −23.16, p < 0.001). JAK inhibitor treatment achieved the largest improvement in both IGA response (RR 3.59, 95% CI 2.66–4.84, p < 0.001) and EASI score (WMD −42.00, 95% CI −48.64 to −35.36, p < 0.001) by week 4 of treatment. Topical JAK inhibitors were significantly more efficacious than oral inhibitors. Upadacitinib treatment for 4 weeks was most effective in reducing EASI score (WMD −53.92, 95% CI −69.26 to −38.58, p < 0.001), while abrocitinib for 4 weeks led to the most effective IGA response (RR 5.47, 95% CI 2.74–10.93, p < 0.001). There was no difference in the frequency of adverse events (AEs) leading to discontinuation; however, JAK inhibitors use, especially abrocitinib, led to a higher incidence of treatment-emergent AEs (RR 1.25, 95% CI 1.10–1.42, p = 0.001).

Conclusion

Our results imply that JAK inhibitors are an effective and safe AD treatment. Nevertheless, further trials with longer duration and head-to-head comparisons of different JAK inhibitors are needed.