Patients with atopic dermatitis and history of eczema herpeticum elicit herpes simplex virus-specific type 2 immune responses

High recurrence rate of eczema herpeticum in moderate/severe atopic dermatitis -TREATgermany registry analysis

BACKGROUND

Eczema herpeticum (EH) is a disseminated skin infection caused by herpes simplex virus in atopic dermatitis (AD) patients. The frequency of EH and the clinical features of EH patients have not yet been investigated in a larger cohort.

METHODS

We sought to investigate the TREATgermany cohort, a multicenter, non-interventional clinical registry of moderately to severely affected AD patients in Germany. Baseline characteristics of patients included between December 2017 and April 2021 were compared between patients without, single, and multiple EH.

RESULTS

Of the 893 patients, 195 (21.8%) had at least one EH. Of the 195 patients with EH, 107 had multiple EH (54.9%), representing 12.0% of the total study population. While there were no differences in demographic characteristics, previous treatment, and disease scores at enrollment (itch, IGA, oSCORAD, EASI), patients with EH had more frequent atopic comorbidities and sensitizations to house dust mite, food, and mold.

DISCUSSION

TREATgermany registry data suggest a high prevalence and recurrence rate of EH, while there appears to be no specific clinical phenotype, besides an increase in allergies, to identify EH patients in the daily routine.

Hohe Rezidivrate des Eczema herpeticatum bei mittelschwerer bis schwerer atopischer Dermatitis - eine TREATgermany Registeranalyse

Hintergrund

Das Eczema herpeticatum (EH) ist eine disseminierte Hautinfektion, die durch Herpes‐simplex‐Viren bei Patienten mit atopischer Dermatitis (AD) verursacht wird. Die Häufigkeit des EH und die klinischen Charakteristika von EH Patienten wurden bisher noch nicht in einer größeren Kohorte untersucht.

Methodik

87 Patienten des TREATgermany Registers, einem multizentrischen, nichtinterventionellen klinischen Register mit moderat bis schwer betroffenen AD‐Patienten in Deutschland, wurden in dieser Analyse betrachtet. Patienten, die zwischen Dezember 2017 und April 2021 in das Register eingeschlossen wurden, wurden unterteilt in die Gruppen ohne, mit einem und mit mehreren EH und basierend auf den klinischen Charakteristika verglichen.

Ergebnisse

Von 893 Patienten berichteten 195 (21,8%) über mindestens eine EH. 107 der 195 Patienten mit EH hatten sogar mehrere EH in der Anamnese (54,9%), was 12,0% der gesamten Studienpopulation entspricht. Während hinsichtlich demographischer Merkmale, Vorbehandlungen und Krankheitsscores (Juckreiz, IGA, oSCORAD, EASI) keine Unterschiede festgestellt wurden, litten Patienten mit EH häufiger an atopischen Begleiterkrankungen und Sensibilisierungen gegen Hausstaubmilben, Nahrungsmittel und Schimmelpilze.

Schlussfolgerungen

Die Daten des TREATgermany‐Registers deuten auf eine hohe Prävalenz und Rezidivrate des EH hin, während es neben einer Häufung von Allergien keinen spezifischen klinischen Phänotyp zu geben scheint, um EH‐Patienten in der täglichen Routine zu identifizieren.

Dupilumab strengthens herpes simplex virus type 1-specific immune responses in atopic dermatitis

BACKGROUND

Impaired virus clearance in a subgroup of atopic dermatitis (AD) patients can lead to severe herpes simplex virus (HSV) infections called eczema herpeticum (EH). We recently identified a type 2 skewed viral immune response in EH patients. Clinical data suggest a reduced incidence of EH in AD patients treated with dupilumab, although immunologic investigations of this phenomenon are still lacking.

OBJECTIVE

We examined the impact of dupilumab on the HSV type 1 (HSV-1) specific immune response in AD, focusing on patients with (ADEH+) and without (ADEH-) a history of EH.

METHODS

Sera and peripheral blood mononuclear cells were collected from ADEH+ and ADEH- patients, a subgroup of whom was receiving dupilumab treatment, and healthy controls. Serum samples were tested for IgE against HSV-1 glycoprotein D (n = 85). Peripheral blood mononuclear cells were stimulated with HSV peptides, and activated CD4+ and CD8+ cells were characterized by flow cytometry after magnetic enrichment via CD154 or CD137 (n = 60). Cytokine production of HSV-1-reactive T-cell lines (n = 33) and MHC-I tetramer+ (HSV-1-UL25) CD8+ T cells was investigated by bead assay and intracellular cytokine staining (n = 21).

RESULTS

We confirmed that HSV-1-specific IgE is elevated in ADEH+ patients. During dupilumab treatment, the IgE levels were significantly decreased, reaching levels of healthy controls. HSV-1-specific TC1 frequencies were elevated in ADEH- patients treated with dupilumab compared to dupilumab-negative patients. There were no changes in the frequencies of HSV-1-specific TH cells while receiving dupilumab therapy. AD patients receiving dupilumab exhibited elevated IFN-γ and reduced IL-4 production in HSV-1-UL25-epitope-specific T cells compared to dupilumab-negative patients.

CONCLUSION

Dupilumab may improve the HSV-1-specific immune response in AD as a result of an increased type I immune response and a reduction of HSV-1-specific IgE.

Diversities of allergic pathologies and their modifiers: Report from the second DGAKI-JSA meeting

In October 2021, researchers from the German Society of Allergy and Clinical Immunology (DGAKI) and from the Japanese Society of Allergology (JSA) focused their attention on the pathological conditions and modifiers of various allergic diseases. Topics included 1) the pathophysiology of IgE/mast cell-mediated allergic diseases; 2) the diagnosis and prevention of IgE/mast cell-mediated diseases; 3) the pathophysiology, diagnosis, and treatment of eosinophilic airway diseases; and 4) host-pathogen interaction and allergic diseases. This report summarizes the panel discussions, which highlighted the importance of recognizing the diversity of genetics, immunological mechanisms, and modifying factors underlying allergic diseases.

Eczema herpeticum in atopic dermatitis

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases leading to pruritic skin lesions. A subset of AD patients exhibits a disseminated severe HSV infection called eczema herpeticum (EH) that can cause life-threatening complications. This review gives an overview of the clinical picture, and characteristics of the patients as well as the diagnosis and therapy of EH. A special focus lies on the pathophysiological hallmarks identified so far that predispose for EH. This aspect covers genetic aberrations, immunological changes, and environmental influences displaying a complex multifactorial situation, which is not completely understood. Type 2 skewing of virus-specific T cells in ADEH⁺ patients has been implicated in immune profile abnormalities, along with impaired functions of dendritic cells and natural killer cells. Furthermore, aberrations in interferon pathway-related genes such as IFNG and IFNGR1 have been identified to increase the risk of EH. IL-4, IL-25, and thymic stromal lymphopoietin (TSLP) are overexpressed in EH, whereas antimicrobial peptides like human β-defensins and LL-37 are reduced. Concerning the epidermal barrier, single nucleotide polymorphisms (SNPs) in skin barrier proteins such as filaggrin were identified in ADEH⁺ patients. A dysbalance of the skin microbiome also contributes to EH due to an increase of Staphylococcus aureus, which provides a supporting role to the viral infection via secreted toxins such as α-toxin. The risk of EH is reduced in AD patients treated with dupilumab. Further research is needed to identify and specifically target risk factors for EH in AD patients.

Atopic Eczema: Pathophysiological Findings as the Beginning of a New Era of Therapeutic Options

Atopic eczema (AE) is a chronic inflammatory disease hallmarked by intense pruritus and eczematous lesions. It depicts one of the most common skin diseases affecting a major part of children and several percentages of adults.Both pathogenesis and pathophysiology are based on complex orchestrated interactions of skin barrier defects, immunological changes, the environment, and an abundance of other contributing factors. Frequently, AE displays the starting point for other allergic diseases such as allergic asthma and rhinoconjunctivitis. Additionally, the risk of developing food allergy is increased. Furthermore, the disease is accompanied by a susceptibility to bacterial, fungal, and viral infections. The development of new therapies received great impetus by an ample research of the pathophysiological mechanisms, leading to a new era in the treatment of severe atopic eczema due to targeted treatments, e.g. the IL-4R alpha specific monoclonal antibody dupilumab.This article provides an overview of the causative and pathophysiological characteristics, the clinical and diagnostic aspects as well as current and future therapeutical possibilities focusing allergic aspects contributing to the course of the disease.

Microbiome of Barrier Organs in Allergy: Who Runs the World? Germs!

Over the last few decades, allergic diseases have been steadily increasing worldwide, a phenomenon that is not yet completely understood. Recent evidence, however, suggests that alterations in the microbiome may be a contributing factor. The microbiome refers to all microorganisms in a habitat including bacteria, fungi, and viruses. Using modern sequencing technologies, we are now capable of detecting and analyzing the human microbiome in more detail than ever before. Epidemiological and experimental studies have indicated that a complex intestinal microbiome supports the development of the immune system during childhood, thus providing protection from allergic diseases, including food allergy. The microbiome becomes an important part of human physiology and forms dynamic relationships with our various barrier systems. For example, bacterial dysbiosis is a hallmark of atopic eczema and correlates with disease progression. Similarly, the lung and nasopharyngeal microbiome is altered in patients with asthma and allergic rhinitis. While these results are interesting, the underlying mechanisms are still unclear and need to be investigated with functional studies. This review gives a short overview of the terminology and methods used in microbiome research before highlighting results concerning the lung, skin, and intestinal microbiome in allergic diseases.

Herpes simplex virus 1 proteins can induce skin inflammation in an atopic dermatitis-like mouse model

Herpes simplex virus type 1 (HSV-1) can induce in certain individuals with atopic dermatitis (AD) severe cutaneous infections that can spread throughout the entire body, a condition named as AD complicated by eczema herpeticum (ADEH). It has been recently found that ADEH patients can produce specific IgE against HSV-1 proteins, which may contribute to lower protection against HSV-1. However, little is known about the capacity of these HSV-1 proteins to produce an inflammatory response at the skin level. In this study, using a mouse model of AD-like dermatitis, three HSV-1 proteins (glycoprotein D -gD-, glycoprotein B -gB- and VP22) were applied on tape-stripped back skin mice in three exposures periods. Ovalbumin (OVA) and 0.9% NaCl were used as positive and negative controls, respectively. Skin samples were obtained for analysis of specific cell components of skin infiltration. The results showed that the viral protein gD induced a statistically significant increase in the number of dermal infiltrating CD3+, CD4+ cells and mast cells compared with the negative control group. gD was also able to induce epidermal thickening and epidermal infiltration of T cells closely related to the one produced in mice sensitized with OVA. However, VP22 and gB contributed to a lesser extent to skin inflammation. These results showed that proteins from HSV-1, especially gD, can have per se an important T cell and mast cell-driven inflammatory potential at the skin level.

Eczema Herpeticum: Clinical and Pathophysiological Aspects

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease in the world. AD is a complex pathology mainly characterized by an impaired skin barrier, immune response dysfunction, and unbalanced skin microbiota. Moreover, AD patients exhibit an increased risk of developing bacterial and viral infections. One of the most current, and potentially life-threatening, viral infection is caused by herpes simplex virus (HSV), which occurs in about 3% of AD patients under the name of eczema herpeticum (EH). Following a first part dedicated to the clinical features, virological diagnosis, and current treatments of EH, this review will focus on the description of the pathophysiology and, more particularly, the presently known predisposing factors to herpetic complications in AD patients. These factors include those related to impairment of the skin barrier such as deficit in filaggrin and anomalies in tight and adherens junctions. In addition, low production of the antimicrobial peptides cathelicidin LL-37 and human β-defensins; overexpression of cytokines such as interleukin (IL)-4, IL-13, IL-25, IL-33, and thymic stromal lymphopoietin (TSLP); or downregulation of type I to III interferons as well as defect in functions of immune cells such as dendritic, natural killer, and regulatory T cells have been involved. Otherwise, genetic polymorphisms and AD topical calcineurin inhibitor treatments have been associated with an increased risk of EH. Finally, dysbiosis of skin microbiota characterized in AD patients by Staphylococcus aureus colonization and toxin secretion, such as α-toxin, has been described as promoting HSV replication and could therefore contribute to EH.

On the surface: Skin microbial exposure contributes to allergic disease

OBJECTIVE

To discuss the skin microbiome modulates immunity by interactions between skin immunology with keratinocytes to combat pathogens. Allergic disorders are classified by immunoglobulin E sensitivity and aberrant TH2 cell responses, and an increasing number of studies have described the associations with skin microbiome fluctuations. In this review, we discuss commensal-epidermal homeostasis and its influence on allergic disease.

DATA SOURCES

All included references were obtained from the PubMed database.

STUDY SELECTIONS

Studies addressing relevant aspects of commensal-epidermal homeostasis, skin microbiome dysbiosis, microbiome-targeted therapeutics, and prevention in allergy were included.

RESULTS

Homeostasis between the commensal microbiome and the epidermis is important in protecting against allergic disease. Commensals promote antiallergic TH1 and TH17 immunophenotypes within the skin and induce keratinocytes to secrete antimicrobial peptides and alarmins that enhance barrier function and antagonize proallergic organisms. Perturbations in this homeostasis, however, is associated with allergic disease development. Atopic dermatitis is associated with decreases in skin commensals and increases in the pathogen, Staphylococcus aureus. Fluctuations in the skin microbiome contributes to decreased barrier dysfunction, allergic sensitization, and TH2 cytokine secretion. Little is known about how the skin microbiome affects food allergy, allergic rhinitis, and asthma, and it is poorly understood how cutaneous inflammation influences systemic allergic responses. Therapies are targeted toward maintenance of the skin barrier, replacement of healthy commensals, and anti-TH2 biologic therapy.

CONCLUSION

Although the effects of commensal-epidermal homeostasis on allergy within the skin are becoming increasingly clear, future studies are necessary to assess its effects on extracutaneous allergic disorders and explore potential therapeutics targeting the skin microbiome.

Pooled safety analysis of baricitinib in adult patients with atopic dermatitis from 8 randomized clinical trials

BACKGROUND

Janus kinase (JAK) inhibition is a new mode of action in atopic dermatitis (AD); clarity about drug class safety considerations in the context of AD is important. Baricitinib, an oral, reversible, selective inhibitor of JAK1/JAK2, is in late-stage development for adult patients with moderate-to-severe AD.

OBJECTIVE

To report pooled safety data for baricitinib in patients with moderate-to-severe AD in the clinical development program including long-term extension (LTE) studies.

METHODS

This analysis included patient-level safety data from six double-blinded, randomized, placebo-controlled studies (one phase 2 and five phase 3), one double-blinded, randomized, LTE study and one open-label LTE study, reported in three data sets: placebo-controlled, 2-mg - 4-mg extended and All-bari AD. Safety outcomes include treatment-emergent adverse events, adverse events of special interest and abnormal laboratory changes. Proportions of patients with events and incidence rates were calculated.

RESULTS

Data were collected for 2531 patients who were given baricitinib for 2247 patient-years (median duration 310 days). The frequency of serious infections, opportunistic infections and conjunctival disorders was low and similar between treatment groups in the placebo-controlled period. The most common serious infections were eczema herpeticum [n = 11, incidence rates (IR) = 0.5], cellulitis (n = 6, IR = 0.3) and pneumonia (n = 3, IR = 0.1). There were four opportunistic infections (IR = 0.2). No malignancies, gastrointestinal perforations, positively adjudicated cardiovascular events or tuberculosis were reported in the placebo-controlled period in baricitinib-treated patients. Frequency of herpes simplex was higher in the 4-mg group (6.1%) vs. the 2-mg (3.6%) and placebo group (2.7%); IRs in the extended data set (2-mg IR = 9.6; 4-mg IR = 14.5) were lower vs. the placebo-controlled data set (2-mg IR = 12.4; 4-mg IR = 21.3). In the All-bari AD data set, there were two positively adjudicated major adverse cardiovascular events (2-mg group): two venous thrombosis events (4-mg group) and one death.

CONCLUSION

This integrated safety analysis in patients with moderate-to-severe AD confirms the established safety profile of baricitinib.

Baseline characteristics, disease severity and treatment history of patients with atopic dermatitis included in the German AD Registry TREATgermany

BACKGROUND

The Atopic Dermatitis (AD) TREATgermany registry was initiated by the German Society for Dermatology (DDG) in 2011 to evaluate the 'real-life' situation of health care for patients with AD.

OBJECTIVES

Interim data analysis on baseline characteristics as well as current and prescribed systemic treatments of the TREATgermany registry patients.

METHODS

Patients (≥18 years) with moderate-to-severe AD [objective (o)SCORAD > 20], or with current or previous anti-inflammatory systemic treatment for AD within 24 months, were included and are followed up over at least 24 months. To assess clinical signs, the eczema area severity index (EASI, 0-72), the oSCORAD (0-83) and the Investigator Global Assessment (IGA; 6-point scale) were used. The disease severity was globally scored by the patients [Patient Global Assessment (PGA); six-step Likert scale]. Disease symptoms were assessed by the patient-oriented eczema measure (POEM, 0-28) and numeric rating scales (NRS, 0-10). Health-related quality of life was measured using the dermatological life quality index (DLQI, 0-30).

RESULTS

A total of 612 patients were recruited across 32 sites between 06/2016 and 01/2019 (mean age: 42.6 ± 14.2 years; mean oSCORAD: 40.8 ± 16.3). The mean POEM score was 16.3 ± 7.5. Pruritus was rated highest among subjective symptoms (NRS: 5.4 ± 2.7). The mean DLQI value was 11.3 ± 7.5. The frequency of arterial hypertension was lower (20.8%) compared with the general population, whilst this was higher for depression (10%). More than 60% of the patients had received systemic glucocorticosteroids, and 36.8% had received cyclosporine A prior to inclusion. Dupilumab was the leading substance documented as either 'current' (12.1%) or 'prescribed' (31.4%) at baseline.

CONCLUSIONS

These 'real-life' data clearly demonstrate the substantial disease burden. Most of TREATgermany patients were already treated with or prescribed dupilumab at baseline. Moreover, current findings indicate the urgent need for further alternative agents in order to achieve a perceptible improvement of quality of life of patients with moderate-to-severe AD.

Pathophysiology of atopic dermatitis

Only few diseases have been studied as extensively and on as many different levels in recent years as atopic dermatitis (AD). One of the reasons why AD is the focus of interest is that it is one of the most common chronic inflammatory skin diseases, affecting up to 30 % of children and 1-10 % of adults. Numerous complex alterations both on the genetic level as well as on the level of innate and adaptive immunity have been identified and form the basis for the characterization of different patient groups and the development of novel diagnostic and therapeutic approaches. Despite the complex pathophysiological and immunological differences, which are closely related to disease stage and severity, as well as the heterogeneity of individual trigger factors, treatment of AD - in particular that of moderate-to-severe AD - was long limited to merely symptomatic and relatively nonspecific immunosuppressive approaches. Since the approval of the first biologic for the treatment of moderate-to-severe adult AD (commercially available in Germany since late 2017), there has been some movement in the field of AD management. The present review highlights recent pathophysiologic insights. Advances in research allow for better characterization of certain patient subgroups and different disease manifestations. In addition, they form the basis of current and future developments in the field of precision medicine in AD.

The role of bacterial skin infections in atopic dermatitis: expert statement and review from the International Eczema Council Skin Infection Group

Patients with atopic dermatitis (AD) have an increased risk of bacterial skin infections, which cause significant morbidity and, if untreated, may become systemic. Staphylococcus aureus colonizes the skin of most patients with AD and is the most common organism to cause infections. Overt bacterial infection is easily recognized by the appearance of weeping lesions, honey‐coloured crusts and pustules. However, the wide variability in clinical presentation of bacterial infection in AD and the inherent features of AD – cutaneous erythema and warmth, oozing associated with oedema, and regional lymphadenopathy – overlap with those of infection, making clinical diagnosis challenging. Furthermore, some features may be masked because of anatomical site‐ and skin‐type‐specific features, and the high frequency of S. aureus colonization in AD makes positive skin swab culture of suspected infection unreliable as a diagnostic tool. The host mechanisms and microbial virulence factors that underlie S. aureus colonization and infection in AD are incompletely understood. The aim of this article is to present the latest evidence from animal and human studies, including recent microbiome research, to define the clinical features of bacterial infections in AD, and to summarize our current understanding of the host and bacterial factors that influence microbial colonization and virulence.

[Atopic dermatitis and general medical comorbidities]

Atopic dermatitis (AD) is one of the most frequent chronic inflammatory skin diseases, characterized by pruritic eczematous lesions. Due to the fact that AD is accompanied by signs of systemic inflammation and that an increased number of novel systemic treatment options are currently emerging, research into general medical comorbidities in moderately to severely affected AD patients has received great impetus in recent years. These studies have confirmed an increased risk of atopic diseases such as allergic asthma in AD patients. Furthermore, an association between AD and dermatological diseases with autoimmune pathophysiology such as vitiligo and alopecia areata has been demonstrated. Moreover, several studies have revealed an increased risk for internal autoimmune diseases in AD patients, e.g. inflammatory bowel disease and rheumatoid arthritis. A differentiated view of the data on AD as a possible risk factor for cardiovascular disease is needed. Large cross-sectional studies in the US revealed a correlation between AD and cardiovascular comorbidities. This has not been confirmed as yet in large German, Danish and Canadian investigations. Whether diverse "coping" strategies in different countries can explain these variances remains to be discussed. In terms of microbial comorbidities, AD patients display a particular susceptibility to viral infections.

[Atopic eczema and microbiome]

BACKGROUND

Atopic eczema is a chronic inflammatory skin disease characterized by skin barrier disruption, inflammation and dysbiosis. Furthermore, atopic eczema is associated with other diseases of the atopic group, such as allergies, rhinoconjunctivitis and asthma. The skin microbiome consists of bacteria, viruses and fungi. Patients suffering from atopic eczema often show an imbalance (dysbiosis) of the microbiome.

OBJECTIVE

It is not yet completely clarified what influence dysbiosis and the cutaneous microbiome have on the development and severity of atopic eczema. Modern sequencing methods will be used to investigate the role of the skin microbiome in the pathogenesis of atopic eczema in the future.

MATERIAL AND METHODS

This article presents and discusses the results of current basic research.

RESULTS

The human skin microbiome differs according to body region, age and gender. It interacts with the skin barrier and the cutaneous immune system. Patients suffering from atopic eczema develop dysbiosis consisting of an increased load of Staphylococcus aureus and a reduction of commensal skin bacteria. The altered skin microbiome in patients suffering from atopic eczema may also affect skin barrier function and inflammatory reactions.

CONCLUSION

Knowledge of the skin microbiome has improved in recent years. This will certainly improve the understanding of the pathogenesis causing atopic eczema. These findings may also form the foundation of new treatment and prevention strategies for atopic eczema in the future.

Severe Atopic Dermatitis in Children

PURPOSE OF REVIEW

Severe atopic dermatitis (AD) in childhood leads to significant morbidity including psychosocial problems and infectious complications. There are only a few approved treatment options for these patients. These include topical corticosteroids and tacrolimus ointment, which are associated with potential side effects.

RECENT FINDINGS

In order to find better and safer treatments, further understanding of AD mechanisms is needed. Primary skin barrier defects play an important role in the pathogenesis of AD. In addition, the suppression of skin barrier functions by Th2 inflammation also plays an important role in the persistence and recurrence of AD. Cytokines in the Th2 pathway, which includes IL-4, IL-13, TSLP, IL-25, IL-31, and IL-33, are potential therapeutic targets in AD. Other potential targets of AD are Janus kinase, phospholipase A2, aryl hydrocarbon receptor, and skin microbiota. A better understanding of the pathogenesis of AD will provide future direction for treatment.