Clinical and histopathological characterization of eczematous eruptions occurring in course of anti IL-17 treatment: a case series and review of the literature

Ixekizumab-induced urticaria is associated with the short duration of remission in psoriasis by activation of mast cells

BACKGROUND

Mast cell degranulation plays a pivotal role in urticaria and is also an early histologic characteristic of psoriasis. However, whether the activation of mast cells contributes to psoriasis recurrence after discontinuation of interleukin (IL)-17A blockers remains unclear.

OBJECTIVE

To investigate the role of mast cells in ixekizumab treatment-associated urticaria (ITAUR) and assess the effect of urticaria eruption on psoriasis relapse.

METHODS

A retrospective analysis was performed on biopsies of patients who experienced psoriasis relapse after discontinuation of ixekizumab. Transcriptomic and histopathologic features were assessed. Patterns were compared between patients with ITAUR and nonurticaria (NUR) as well as psoriasis-like mice with mast cell activation or inactivation.

RESULTS

Patients with ITAUR experienced early relapse compared with NUR group after treatment withdrawal. Transcriptomic and histopathologic analyses revealed that patients with ITAUR had an elevated proportion of mast cells in resolved skin. Especially, the proportion of IL-17A+ mast cells was inversely correlated with the duration of remission.

LIMITATIONS

The mechanism of mast cell activation in ITAUR has not been precisely elucidated.

CONCLUSION

Ixekizumab treatment increases IL-17A+ mast cells in lesions of ITAUR, which is associated with early psoriasis relapse after ixekizumab withdrawal.

Paradoxical psoriasis induced by IL-17 antagonists

Background The paradoxical occurrence of psoriasis triggered by Interleukin-17 (IL-17) inhibitors is notable due to its prominent symptoms and the therapeutic dilemma it presents for follow-up care. Objective To describe cases in our clinic, perform an in-depth literature review, and suggest the most probable mechanisms of action. Method We conducted a literature review on published cases of IL-17 inhibitor-induced psoriasis. Results We found 22 articles reporting 30 cases of IL-17 inhibitor-induced paradoxical psoriasis, primarily observed in patients with a previous psoriasis history. Almost 60% of cases showed a change in lesion morphology, with the plaque or pustular type being prevalent. About 73.3% of patients had to discontinue the implicated drug, leading to partial or complete symptom resolution. The mechanism behind this response seemed to involve IL-17 inhibitors downregulating Tumour Necrosis Factor alpha (TNF-α), subsequently upregulating plasmacytoid dendritic cells and triggering unopposed IFN-alpha (IFN-α) production. Limitation Data are confined to case reports and case series. Conclusion More assertive measures are recommended for treating paradoxical psoriasis induced by IL-17 inhibitors than those caused by TNF-α inhibitors. Reintroducing an IL-17 inhibitor is not advised, as patients did not show improvement.

Assessment of safety profile of secukinumab in real-world scenario using United States food and drug administration adverse event reporting system database

Secukinumab is an anti-IL-17 monoclonal antibody approved for treating psoriasis and various arthritides. A comprehensive evaluation of its safety, especially in a real-world setting, is necessary. This study aimed to describe the adverse events (AE) associated with secukinumab use using the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database. FAERS data files containing AE reports from 2015 to 2021 were downloaded for data mining. Primary or secondary suspect medications indicated for psoriasis were identified and analyzed. Medical dictionary for regulatory activities (MedDRA version 24.1) was used to analyze the AE terms. To detect potential safety signals of AE from secukinumab use, disproportionality analysis was used. A total of 365,590 adverse event reports were identified; of these, 44,761 reports involved the use of secukinumab. Safety signals were identified for ocular infections and gastrointestinal adverse events at the standardised MedDRA query level. Safety signals for oral candidiasis, oral herpes, conjunctivitis, eye infections, and ulcerative colitis were identified at the preferred term level. The findings of our study are consistent with those of earlier studies, such as the increased risk of infections and inflammatory bowel disease. However, our study also identified additional safety signals that need to be further evaluated.

Development of a clinical algorithm to predict phenotypic switches between atopic dermatitis and psoriasis (the "Flip-Flop" phenomenon)

BACKGROUND

Atopic dermatitis (AD) and psoriasis vulgaris (PV) are almost mutually exclusive diseases with different immune polarizations, mechanisms and therapeutic targets. Switches to the other disease ("Flip-Flop" [FF] phenomenon) can occur with or without systemic treatment and are often referred to as paradoxical reactions under biological therapy.

METHODS

The objective was to develop a diagnostic algorithm by combining clinical criteria of AD and PV to identify FF patients. The algorithm was prospectively validated in patients enrolled in the CK-CARE registry in Bonn, Germany. Afterward, algorithm refinements were implemented based on machine learning.

RESULTS

Three hundred adult Caucasian patients were included in the validation study (n = 238 with AD, n = 49 with PV, n = 13 with FF; mean age 41.2 years; n = 161 [53.7%] female). The total FF scores of the PV and AD groups differed significantly from the FF group in the validation data (p < .001). The predictive mean generalized Youden-Index of the initial model was 78.9% [95% confidence interval 72.0%-85.6%] and the accuracy was 89.7%. Disease group-specific sensitivity was 100% (FF), 95.0% (AD), and 61.2% (PV). The specificity was 89.2% (FF), 100% (AD), and 100% (PV), respectively.

CONCLUSION

The FF algorithm represents the first validated tool to identify FF patients.

Development of IL-17A inhibitor-induced atopic dermatitis-like rash in psoriasis patients: Insights into immune shift

Cases of atopic dermatitis (AD)-like rash induced by IL-17A inhibitor secukinumab treatment (SI-AD) have been recently reported in psoriasis patients. To identify immune and inflammatory factors expression in SI-AD. A panel of 15 immune and inflammatory factors in peripheral blood samples from various groups, including patients with patients with SI-AD, psoriasis with secukinumab (S-stable), advanced psoriasis patients (Advanced) and healthy controls (HC). Interleukin-10 (IL-10), IL-4 and IL-17A were detected in skin tissue biopsy samples by immunohistochemistry and real-time quantitative polymerase chain reaction. The immunoglobulin E levels in the SI-AD patients exceeded normal values. The IL-10 levels in SI-AD patients were higher than those in S-stable patients, advanced patients and HC. The IL-4 levels in SI-AD patients were higher than that in S-stable patients and HC. The IL-17A levels in SI-AD patients were higher than those in advanced psoriasis patients and HC, but no significant differences were observed between SI-AD patients and S-stable patients. IL-10 and IL-4 levels were higher in AD-like rashes than in healthy skin, while IL-17A did not differ significantly between the two. Upon discontinuing secukinumab, and switching to oral cyclosporine, antihistamines, Janus kinase 1 inhibitor and topical glucocorticoids, SI-AD patients experienced significant improvement in their skin lesions. Upon reexamination, all 15 immune and inflammatory factors returned to normal levels. Immune shift from Th17 towards Th2 may occur in SI-AD, as indicated by abnormal expression of multiple immune and inflammatory factors observed in peripheral blood and skin tissues.

Predictive factors of atopic-like dermatitis induced by IL-17A inhibitors in patients with psoriasis: A 2-year follow-up study

BACKGROUND

Atopic-like dermatitis (ALD) is a common side effect of interleukin-17A (IL-17A) inhibitors.

OBJECTIVE

To determine the prevalence, risk factors, outcomes and treatment of ALD in a cohort of psoriasis patients treated with IL-17A inhibitors.

METHODS

This retrospective study included 226 psoriasis patients treated with an IL-17A inhibitor in our dermatology department between July 2020 and July 2022. The patients were reviewed over 2 years. A logistic regression model in rare events data (relogit) was used to predict the risk factors for ALD.

RESULTS

Of the 226 patients, 14 had ALD. Data including age, body mass index, IL-17A inhibitor use, personal and family history of atopic disease, pet ownership history, and immunoglobulin E (IgE) levels were analysed using the relogit regression model. It indicated a personal history of atopic disease (odd ratio [OR] 27.830, 95% confidence interval [CI] 3.801-203.770; p = 0.001) and elevated IgE levels (OR 5.867, 95% CI 1.131-30.434; p = 0.035) as independent predictors of incident ALD. In one patient, anti-IL-17A therapy was discontinued, and treatment was switched to tofacitinib. Thirteen patients who continued with IL-17A inhibitor were treated with topical therapy and/or antihistamines, and their ALD was partially or completely resolved.

CONCLUSION

In this study, the incidence rate of ALD was 6.19%. Elevated IgE levels and a personal history of atopic disease were found to be the risk factors for ALD. Our study findings suggest that treatment should be provided based on the severity of psoriasis and incident ALD. Prior to treatment, psoriasis patients who have the risk factors for ALD should be informed of the possible development of ALD, and alternative psoriatic therapeutic options should be considered if severe ALD develops.

RETRACTED ARTICLE: Secukinumab-induced paradoxical skin lesions, but successful treatment with tofacitinib in SAPHO syndrome: a case report

We, the Editors and Publisher of Journal of Dermatological Treatment, have retracted the following article:Li Luan & Chengzhi Lv (2023) Secukinumab-induced paradoxical skin lesions, but successful treatment with tofacitinib in SAPHO syndrome: a case report, Journal of Dermatological Treatment, DOI: 10.1080/09546634.2023.2193662Since publication of the article, concerns were raised by a reader regarding the lack of recorded patient consent to publish. Upon further investigation, it was determined that written consent for the publication was not obtained by the authors. The authors were contacted for an explanation and confirmed written consent for the publication was not obtained.As this represents a breach of the journal's editorial policies, we are therefore retracting the article. The corresponding author listed in this publication has been informed.We have been informed in our decision-making by our editorial policies and the COPE guidelines.The retraction article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as 'Retracted'.

Secukinumab-induced IgA vasculitis in a patient with psoriatic arthritis

OBJECTIVES

Secukinumab (SEC) is an effective and widely used drug in psoriatic disease and axial spondyloarthritis. However, SEC has been found to be associated with inflammatory conditions and vasculitis. These inflammatory adverse effects may complicate the treatment of underlying disease, and clinicians may experience difficulties in recognizing and managing this unusual condition.

CASE REPORT

A man aged 56 years with psoriatic disease refractory to conventional disease-modifying antirheumatic drugs was given adalimumab for 6 weeks, then switched to SEC when his psoriatic lesions were exacerbated. After 3 weeks of SEC treatment, he developed systemic features of IgA vasculitis while his skin lesions and arthritis persisted.

CONCLUSIONS

Although SEC-related inflammatory adverse events, including vasculitis, are rarely encountered in clinical practice, it is essential to recognize them because they can be mistaken as a component of the underlying inflammatory disease. In addition, the dramatic improvement in many cases after the cessation of SEC underlines the importance of making an accurate diagnosis. Pathogenetically, these adverse events are likely to be paradoxical reactions, except for SEC-induced inflammatory bowel diseases. However, in many aspects, their pathogenesis is controversial and needs clarification.

Author reply to: Comment on: 'Eczematous drug eruption in patients with psoriasis under anti-interleukin-17A: does interleukin-22 play a key role?'

Eczematous drug eruption during biological treatments represents novel and difficult-to-manage reactions, with a still unexplained pathogenesis

In patients treated with IL-17 inhibitors for psoriasis, eczematous drug eruptions skin lesions mainly express Th2/Th22 features, with a central role played by IL-22.

Real-life experience with ixekizumab in plaque psoriasis: a multi-center, retrospective, 3-year study

BACKGROUND

Confirmatory data on the long-term effectiveness and safety of ixekizumab in psoriatic patients from real-world studies are needed.

OBJECTIVES

The primary aim was to evaluate the 3-year drug survival of ixekizumab in the treatment of patients with moderate-to-severe plaque psoriasis, in a multicenter real-world setting. The secondary aim was to assess the influence of predictive factors on the drug survival of ixekizumab.

METHODS

A retrospective analysis was performed on a cohort of patients with chronic plaque psoriasis, who received at least one dose of ixekizumab before December 2018. The drug survival analysis was performed and descriptively analyzed using Kaplan-Meier survival curves. Multivariable Cox regression analyses were carried out including variables considered to be of clinical importance.

RESULTS

A total of 306 patients were enrolled. The overall drug survival at 12, 24, and 36 months of treatment with ixekizumab was 92.11%, 83.85%, and 80.19%, respectively. A higher probability (HR 2.34) of drug withdrawal was found among patients who had already received an anti-IL-17 agent compared with bio-naive patients (p 0.017).

CONCLUSIONS

We found that ixekizumab is a biological agent characterized by long-term effectiveness, not influenced by several clinical factors and associated with a good safety profile.

Treatment of paradoxical eczematous eruption in psoriasis treated with secukinumab: A case report

RATIONALE

Eczematous eruption is an increasingly recognized form of drug-related eruption, typically reported in association with interleukin 17 (IL-17)A inhibitors. However, severe paradoxical eczematous eruption due to IL-17A inhibitors has been rarely reported. Herein, we reported a case of a man with severe psoriasis with erythematous scaly plaques on the scalp, trunk, and arms and legs after the administration of secukinumab was initiated.

PATIENT CONCERNS

We reported a case of a 20-year-old man with severe psoriasis with erythematous scaly plaques on the scalp, trunk, and arms and legs after the administration of secukinumab was initiated. A skin biopsy was performed. It revealed spongiotic dermatitis consistent with eczematous reaction. Direct and indirect immunofluorescence assays were negative.

DIAGNOSES

He was diagnosed with eczematous eruption.

INTERVENTIONS

Discontinuation of secukinumab and administration of cyclosporine and prednisone were considered.

OUTCOMES

Significant improvement was observed, with no adverse events.

CONCLUSION

Our case shows that eczematous eruption can paradoxically occur in patients on IL-17A inhibitors and this report is expected to increase awareness of the rising number of cutaneous eruptions related to biological agents.

IL-17A and TNF-α inhibitors induce multiple molecular changes in psoriasis

Adalimumab and secukinumab are commonly used for moderate to severe psoriasis vulgaris (PV). Although distinct individual responses to and impaired effectiveness of these biological agents occur occasionally, little is known about the underlying reasons. Here, we report a proteomic analysis of psoriatic lesions from patients treated with these drugs using data-independent acquisition mass spectrometry (DIA-MS). Thousands of differentially expressed proteins (DEPs) changed over 12 weeks of treatment. Network analysis showed that DEPs could interact and induce transformation in matrix components, metabolic regulation, and immune response. The results of parallel reaction monitoring (PRM) analysis suggested that S100s, STAT1, KRT2, TYMP, SOD2, HSP90AB1, TFRC, and COL5A1 were the most significantly changed proteins in both groups. There was a positive association between the Psoriasis Area and Severity Index (PASI) score and three proteins (TFRC, IMPDH2, KRT2). Our study findings suggest that inhibition of IL-17A and TNF-α can induce changes in multiple molecules in psoriatic lesions and have an overlapping influence on the immune response and process through direct or indirect effects.

The immunoregulatory effects of natural products on psoriasis via its action on Th17 cells versus regulatory T cells balance

Psoriasis is an incurable, chronic inflammatory disease, which brings a substantial burden on individuals and society. Currently, the treatment of psoriasis has entered the era of biologics, but its highly targeting of inflammatory mediators may enable the immune response to circumvent the blockade, leading to disease recurrence, or other clinical and immunological characteristics. Therefore, the discovery of new therapies that have the ability of multidirectional regulation on immunity and maintain the dynamic balance of immunity in psoriasis, may be the key to the treatment of the disease. Natural products extracted from herbal medicines have synergistic effects to alleviate psoriasis and its comorbidities because of their structural diversity and multiple active mechanisms. To date, the characteristics of natural products regulating T helper 17 (Th17) cells/regulatory T (Treg) cells balance in the treatment of psoriasis have attracted more and more attention from basic and clinical studies. In this review, we systematically introduced the natural products regulating the balance of Th17/Treg and their specific mechanism of action, finding Datura metel L, Grape seed proanthocyanidin extract (GSPE), Thymol, Kaempferol, Aloperine, Abietic acid (AA), Isogarcinol, Luteolin reduced the frequency and function of Th17 cells and simultaneously increased that of Treg cells. It is expected that our work can provide a reference for clinicians in drug use.

Pathogenesis of Paradoxical Reactions Associated with Targeted Biologic Agents for Inflammatory Skin Diseases

Targeted biologic agents have dramatically changed the therapeutic landscape for immune-mediated inflammatory diseases, particularly in rheumatology and dermatology. Their introduction has resulted in a paradigm shift, i.e., they produce significant clinical improvements in most patients with such diseases. Nevertheless, a variety of adverse reactions associated with these agents have been observed, including so-called paradoxical reactions (PRs), which are a new class of adverse events. PRs involve the de novo development or worsening of immune-mediated inflammatory disease during treatment with a targeted biologic agent that is commonly used to treat the idiopathic counterpart of the drug-induced reaction. In addition, the efficacy of biologic agents targeting individual cytokines and the existence of PRs to them have provided proof that cytokines are key drivers of various immune-mediated inflammatory diseases and helped researchers elucidate the molecular pathways underlying the pathophysiology of these diseases. Here, a comprehensive review of the targeted biologic agents used to treat immune-mediated inflammatory diseases, particularly psoriasis and atopic dermatitis, is provided, with a specific focus on biologic agents that inhibit cytokine signaling involving tumor necrosis factor-α, interleukin (IL)-12/23 (p40), IL-17A (and the IL-17 receptor [R]), IL-23 (p19), and the IL-4Rα, and their associated PRs. The characteristic clinical manifestations and potential immunological mechanisms of the PRs induced by these biologic agents are also reviewed.

Dupilumab-Associated Adverse Events During Treatment of Allergic Diseases

Among the new biological therapies for atopic diseases, dupilumab is a fully human monoclonal antibody directed against IL-4Rα, the common chain of interleukin-4 and interleukin-13 receptors. Dupilumab showed clinical improvements in patients with atopic dermatitis, asthma, and chronic rhinosinusitis and is currently under development for other indications. While dupilumab is considered to be well tolerated, a number of recent publications have reported various adverse events. This review aims to summarize the current knowledge about these adverse events, which may help clinicians to improve the follow-up of patients on dupilumab. Injection-site reactions are the most common reported adverse event. However, dupilumab has also been shown to cause ophthalmic complications (e.g., dry eyes, conjunctivitis, blepharitis, keratitis, and ocular pruritus), head and neck dermatitis, onset of psoriatic lesions, progression of cutaneous T-cell lymphoma exacerbation, alopecia areata, hypereosinophilia, and arthritis. Most are managed during dupilumab treatment continuation, but some (e.g., severe conjunctivitis) may result in a discontinuation of treatment. Their molecular origin is unclear and requires further investigations. Among other hypothesis, it has been suggested that T helper (Th)2-mediated pathway inhibition may worsen Th1/Th17-dependent immune responses. An ophthalmological examination for the presence of potential predictive indicators of ophthalmic adverse events is recommended before initiation of dupilumab therapy.

Review of secukinumab-induced adverse events of special interest and its potential pathogenesis

Although secukinumab has demonstrated high efficacy and favorable safety in moderate-to-severe psoriasis and psoriatic arthritis, patients developing adverse events of special interest (AESI) were reported increasingly in real-world practice. A systematic literature search of the PubMed database was conducted to identify clinical studies or case reports on secukinumab-induced AESI. More than 1077 patients (aged 18-74 years) from 55 studies were reported to have 24 AESI 3 days to 96 weeks after secukinumab treatment. The four most common AESI was inflammatory bowel disease (n > 1000), eczematous drug eruption (n > 30), drug-associated vasculitis (n = 8), and drug-induced lupus erythematosus (n = 4). Most of these AESI were only mild to moderately severe and resolved after secukinumab discontinuation without or with symptomatic treatment. Secukinumab has the potential to develop a number of AESI by probably dysregulating the different expression of polar T-cell axes (Th1, Th2, Th17, Th22, and/or Treg) and driving various cytokines in some patients. Physicians should be aware of these AESI for timely diagnosis and proper treatment. This article is protected by copyright. All rights reserved.

Eczematous drug eruption in patients with psoriasis under anti-interleukin-17A: does interleukin-22 play a key role?

BACKGROUND

Eczematous drug eruption (EDE) is a spongiotic skin reaction in response to systemic medications. To date, EDE has been described in patients treated with anti-interleukin (IL)-17A monoclonal antibodies with a prevalence of 2.2%-12.1%.

AIM

To describe the clinical and histological features and the skin cytokine milieu in patients with EDE induced by anti-IL-17A biologics.

METHODS

This was a prospective study, enrolling patients with psoriasis who developed EDE during treatment with two anti-IL-17 biologics, ixekizumab and secukinumab, from June 2019 to April 2021. Skin biopsies were taken from all patients: a 5-mm lesional biopsy (LB) and a 3-mm nonlesional biopsy (NLB). The LB sample was split into two parts, one for histological examination and the other for cytokine profile evaluation.

RESULTS

During the study period, treatment with an anti-IL-17A drug was given to 289 patients of whom 8 (2.8%) developed EDE during the treatment. Histopathological evaluation suggested a diagnosis of spongiotic dermatitis in all eight patients. Cytokine gene expression showed a predominance of T helper (Th)2/Th22 cytokines in EDE lesions with a large increase in IL-4, IL-22 and S100A7 levels in both LB and NLB samples compared with healthy skin. IL-4, IL-22 and S100A7 were significantly higher in LB compared with NLB samples. IL-26 levels were also significantly increased in both LB and NLB compared with healthy skin, whereas low levels of IL-23A were found in both LB and NLB.

CONCLUSION

Eczematous drug eruption skin lesions have mainly Th2/Th22 features, with IL-22 playing a major role in their pathogenesis. EDE seems to be the result of an imbalance towards a Th2/Th22 response, secondary to the blockade of IL-17A activity.

TWEAK functions with TNF and IL-17 on keratinocytes and is a potential target for psoriasis therapy

[Figure: see text].

So close, and yet so far away: The dichotomy of the specific immune response and inflammation in psoriasis and atopic dermatitis

Characterization of the complex interplay between cytokines, chemokines and microorganisms has led to a better understanding of the pathogenesis of both psoriasis and AD and resulted in new therapeutics targeting distinct immune responses. Psoriasis and AD share many characteristics: they are highly prevalent, chronic, cause primarily skin inflammation, but are associated with comorbidities, and come with a devastating quality of life due to itch and stigmatization. However, the pathogenesis of psoriasis and AD is opposing - psoriasis is dominated by a Th17 immune response that causes neutrophil migration, induction of innate immunity and exaggerated epithelial metabolism. Leading cytokines of this Th17 immune response are IL-17A and F, IL-22 and TNF-a. AD is characterized by Th2 immunity characterized by the signature cytokines IL-4 and IL-13 leading to an impaired epidermal barrier, dampened innate immunity and eosinophil migration. This review compares genetics, microbiome and T-cell infiltrate and resulting epithelial response in psoriasis and AD. Whilst the antagonistic course of psoriasis and AD is confirmed by response to specific biologics targeting the key cytokines of inflammation in psoriasis and AD, respectively, clinically overlapping phenotypes are challenging in our daily clinical practice. We conclude this review by summarizing what is known about these mixed phenotypes and how the identification of clinically relevant endotypes and molecular-driven decision-making is the next step in the field of dermato-immunology.

Use of brodalumab for the treatment of chronic plaque psoriasis: a one-year real-life study in the Lazio region, Italy

Background: Information is limited from real-life studies evaluating the efficacy and safety of brodalumab.Research design and methods: In this real-life study, we retrospectively examined a database of 90 patients with moderate-to-severe psoriasis treated with brodalumab (210 mg, s.c.) and followed for 1 year. Disease severity and treatment response were assessed by the Psoriasis Area and Severity Index (PASI) at baseline and after 4, 12, 24, 36, and 48 weeks. Predictors of a PASI response were evaluated by logistic regression.Results: After 48 weeks, 92.2% of patients (mean age 50.2 ± 15 years) treated with brodalumab achieved a PASI score of <3. PASI score decreased from 17.4 ± 10.3 at baseline to 1.7 ± 3.9 and 1.4 ± 3.7 at 12 and 24 weeks, and PASI 75, 90, and 100 response was achieved in 87.3%, 81.8%, and 72.7% of patients, respectively, at 48 weeks.Univariate regression revealed that previous exposure to anti-IL17A treatment was associated with poorer PASI response between 36 and 48 weeks. In difficult-to-treat cases previously having failed with other biologics, brodalumab significantly improved outcome, leading to complete remission.Conclusion: Brodalumab was observed to be effective and safe in patients with moderate-to-severe chronic psoriasis in a real-world setting.

From Messengers to Receptors in Psoriasis: The Role of IL-17RA in Disease and Treatment

The paradigm of psoriasis as a Th17-driven disease has evolved in the last years towards a much deeper knowledge of the complex pathways, mechanisms, cells, and messengers involved, highlighting the crucial role played by the IL-17 family of cytokines. All IL-17 isoforms signal through IL-17R. Five subunits of IL-17R have been described to date, which couple to form a homo- or hetero-receptor complex. Characteristically, IL-17RA is a common subunit in all hetero-receptors. IL-17RA has unique structural—containing a SEFIR/TILL domain—and functional—requiring ACT-1 for signaling—properties, enabling Th17 cells to act as a bridge between innate and adaptive immune cells. In psoriasis, IL-17RA plays a key role in pathogenesis based on: (a) IL-17A, IL-17F, and other IL-17 isoforms are involved in disease development; and (b) IL-17RA is essential for signaling of all IL-17 cytokines but IL-17D, whose receptor has not been identified to date. This article reviews current evidence on the biology and role of the IL-17 family of cytokines and receptors, with focus on IL-17RA, in psoriasis and some related comorbidities, and puts them in context with current and upcoming treatments.

Eczematous Drug Eruptions

Eczematous drug eruptions are a heterogenous group of skin reactions that resemble eczema both clinically and histologically. We reviewed the literature and cataloged the systemically administered medications that cause these eruptions, along with their characteristic clinical presentations. We identified three primary pathophysiologic etiologies: (1) cutaneous immunomodulation, (2) skin dehydration, and (3) delayed hypersensitivity. Notably, eczematous eruptions caused by altered immunity in the skin may be increasing in incidence as some responsible drugs, in particular biologic therapies (such as tumor necrosis factor-α and interleukin-17 inhibitors) and targeted cancer treatments (including immune checkpoint inhibitors and epidermal growth factor receptor inhibitors), become more commonly employed in clinical practice. Other notable causes of eczematous eruptions include antiviral agents for hepatitis C virus and cardiovascular medications in elderly individuals, and notable subtypes of eczematous reactions include systemic contact dermatitis and photoallergic reactions, which are also discussed. The diagnostic gold standard is drug rechallenge and most reactions may be treated effectively with emollients, topical corticosteroids, and oral antihistamines.

Psoriasis

Psoriasis is a common, chronic papulosquamous skin disease occurring worldwide, presenting at any age, and leading to a substantial burden for individuals and society. It is associated with several important medical conditions, including depression, psoriatic arthritis, and cardiometabolic syndrome. Its most common form, chronic plaque or psoriasis vulgaris, is a consequence of genetic susceptibility, particularly in the presence of the HLA-C*06:02 risk allele, and of environmental triggers such as streptococcal infection, stress, smoking, obesity, and alcohol consumption. There are several phenotypes and research has separated pustular from chronic plaque forms. Immunological and genetic studies have identified IL-17 and IL-23 as key drivers of psoriasis pathogenesis. Immune targeting of these cytokines and of TNFα by biological therapies has revolutionised the care of severe chronic plaque disease. Psoriasis cannot currently be cured, but management should aim to minimise physical and psychological harm by treating patients early in the disease process, identifying and preventing associated multimorbidity, instilling lifestyle modifications, and employing a personalised approach to treatment.

RNA-Seq Identifies Marked Th17 Cell Activation and Altered CFTR Expression in Different Atopic Dermatitis Subtypes in Chinese Han Populations

Background

Patients with atopic dermatitis (AD) exhibit phenotypic variability in ethnicity and IgE status. In addition, some patients develop other allergic conditions, such as allergic rhinitis (AR), in subsequent life. Understanding the heterogeneity of AD would be beneficial to phenotype-specific therapies.

Methods

Twenty-eight Chinese AD patients and 8 healthy volunteers were enrolled in the study. High-throughput transcriptome sequencing was conducted on lesional and nonlesional skin samples from 10 AD patients and matched normal skin samples from 5 healthy volunteers. Identification of differentially expressed genes (DEGs), KEGG pathway analyses, and sample cluster analyses were conducted in the R software environment using the DEseq2, ClusterProfiler, and pheatmap R packages, respectively. qRT-PCR, Western blotting, and ELISA were used to detect gene expression levels among subtypes. Correlation analysis was performed to further investigate their correlation with disease severity.

Results

A total of 25,798 genes were detected per sample. Subgroup differential expression analysis and functional enrichment analysis revealed significant changes in the IL17 signaling pathway in Chinese EAD patients but not in IAD patients. DEGs enriched in cytokine-cytokine receptor interactions and gland secretion were considered to be associated with atopic march. Further investigations confirmed a marked IL17A upregulation in Chinese EAD with a positive relationship with total IgE level and AD severity. In addition, increased IL17A in AD patients with AR demonstrated a closer association with AR severity than IL4R. Moreover, AQP5 and CFTR were decreased in the lesions of AD patients with AR. The CFTR mRNA expression level was negatively associated with the skin IL17A level and AR severity.

Conclusion

Our research characterized marked Th17 activation in Chinese EAD patients, and altered expression of IL17A, IL4R, AQP5, and CFTR in AD patients with AR was associated with AR severity. It partially explained the phenotypic differences of AD subtypes and provided potential references for endotype-targeted therapy.

Drug-induced psoriasiform alopecia associated with interleukin-17 inhibitor therapy

Drug-induced psoriasiform alopecia is an increasingly recognized form of alopecia mostly reported in association with TNF-alpha inhibitors. However, drug-induced psoriasiform alopecia in association with IL-17A inhibitors has not been described. We present a 62-year-old woman with severe psoriasis who developed new psoriatic plaques on the scalp with alopecia after initiating ixekizumab (anti-IL-17A). Scalp biopsy specimens revealed a non-cicatricial alopecia with increased telogen/catagen follicles, atrophy of the sebaceous glands, peribulbar and perifollicular inflammation with frequent lymphocytes, plasma cells, eosinophils, psoriasiform dermatitis, and lack of intra-corneal or intra-epidermal neutrophils. Overall, the clinical and histopathologic findings were most compatible with a drug-induced psoriasiform alopecia in association with IL-17A inhibitor therapy. Our case shows that drug-induced psoriasiform alopecia can paradoxically occur in patients on IL-17A inhibitor therapy and contributes to the growing list of cutaneous eruptions associated with biologic agents.

Real-world evaluation of "Eczema in psoriatico": Bridging the gap between dermatology and dermatopathology

The diagnosis of psoriasis is mainly made by clinical examination but on some occasions according to the localization or duration of the lesions when spongiosis is more prominent, it can be challenging and may be considered as overlapping eczema. To evaluate the patients for "eczema in psoriatico" and to present the differences between psoriasis. Biopsy outcomes of thirty-one patients who were histologically diagnosed with psoriasis and psoriasiform dermatitis because of the erythematous and scaly plaque lesions located on hands and feet, between 2013 and 2015, were evaluated retrospectively. Histopathologic findings compatible with psoriasis and accompanied by spongiosis and spongiotic vesicles were evaluated as eczema in psoriatico and compared with psoriasis. In this study thirty-one patients, including 18 patients with eczema in psoriatico and 13 patients with psoriasis of hands and/or feet were included. Of the 31 patients, 15 (48.4%) were women and 16 (51.6%) were men, in 61.3% of cases, biopsies were taken from hands (61.1% of "eczema in psoriatico", 61.5% of psoriasis) and 38.7% from feet (38.9% of "eczema in psoriatico", 38.5% of psoriasis). There was a statistically significant difference between two groups in terms of parakeratosis severity and distribution, the presence of neutrophil and plasma in stratum corneum, the presence of granular layer loss and suprapapillar plate thinning, the shape of retes, the presence of lymphocytic exocytosis, spongiosis and spongiotic vesicles, the intensity of infiltrates in the papillar dermis and the presence of dermal edema (P < .05). Histology supports a continuum between psoriasis and eczema that share histological similarities and at the same time should be considered a separate entity, eczema in psoriatico.

The IL-23/IL-17 Pathway in Inflammatory Skin Diseases: From Bench to Bedside

Interleukin-17 (IL-17) is an essential proinflammatory cytokine, which is mainly secreted by the CD4⁺ helper T cells (Th17 cells) and subsets of innate lymphoid cells. IL-17A is associated with the pathogenesis of inflammatory diseases, including psoriasis, atopic dermatitis, hidradenitis suppurativa, alopecia areata, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Interleukin-23 (IL-23) plays a pivotal role in stimulating the production of IL-17 by activating the Th17 cells. The IL-23/IL-17 axis is an important pathway for targeted therapy for inflammatory diseases. Emerging evidence from clinical trials has shown that monoclonal antibodies against IL-23, IL-17, and tumor necrosis factor are effective in the treatment of patients with psoriasis, atopic dermatitis, hidradenitis suppurativa, pityriasis rubra pilaris, pemphigus, and systemic sclerosis. Here, we summarize the latest knowledge about the biology, signaling, and pathophysiological functions of the IL-23/IL-17 axis in inflammatory skin diseases. The currently available biologics targeting the axis is also discussed.