Inborn Error of Immunity or Atopic Dermatitis: When to be Concerned and How to Investigate

Dermatologic presentations of hyper IgE syndrome in pediatric patients

BACKGROUND

Hyper-IgE Syndrome, also known as Job's syndrome, is a rare primary immunodeficiency disorder characterized by recurrent infections and elevated levels of immunoglobulin E. While respiratory and systemic manifestations have been more emphasized, dermatological manifestations in Hyper-IgE Syndrome also play a significant role in disease presentation.

METHODS

This narrative review explores the dermatologic presentations of Hyper-IgE Syndrome in pediatric populations, including descriptions, associated symptoms/findings, and available treatment options.

RESULTS AND CONCLUSION

Neonatal rash, mucocutaneous candidiasis, noma neonatorum, psoriasis, cold staphylococcal abscesses, and candida onychomycosis are among the dermatological manifestations of Hyper-IgE Syndrome. Each manifestation has unique characteristics and treatment considerations, necessitating accurate recognition and diagnosis for effective management. Optimal treatment strategies involve a combination of supportive care, topical/systemic therapies, antifungal medications, and surgical interventions when necessary. Further research is needed to enhance our understanding of these manifestations and evaluate treatment modalities for individuals affected by Hyper-IgE Syndrome.

European Guideline (EuroGuiDerm) on atopic eczema: Living update

The evidence- and consensus-based living guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. The original EuroGuiDerm Guideline on atopic eczema was published in June 2022. Since then, the part of the guideline dealing with systemic therapy has been updated twice. This paper summarizes the results of the second update. Twenty-eight experts (including clinicians and patient representatives) from 12 European countries participated. The updated guideline provides guidance on which patients should be treated with systemic therapies, as well as recommendations and detailed information on each systemic drug. The systemic treatment options discussed in the guideline comprise conventional immunosuppressive drugs (azathioprine, ciclosporin, glucocorticosteroids, methotrexate and mycophenolate mofetil), biologics (dupilumab, lebrikizumab, nemolizumab and tralokinumab) and Janus kinase (JAK) inhibitors (abrocitinib, baricitinib and upadacitinib). Additionally, the updated guidelines address considerations for paediatric, adolescent, pregnant and breastfeeding patients. For all other aspects, please refer to the 2022 version.

Inborn errors of immunity with atopic phenotypes in the allergy and immunology clinic: a practical review

PURPOSE OF REVIEW

Inborn errors of immunity with atopic phenotypes (IEIwA) are a subgroup of IEI that may present with severe and/or multiple atopic clinical manifestations. Because of their specific clinical management and prognosis, it is important to distinguish IEIwA from multifactorial allergic diseases. We aimed to review the main clinical manifestations associated with IEIwA and summarize the available data regarding the precision medicine approach for these conditions.

RECENT FINDINGS

IEIwA include more than 50 monogenic disorders marked by different immune dysregulation mechanisms such as alterations in cytokine signaling, T cell receptor function, mast cell activation, and skin barrier integrity. A critical role in diagnosis is played by advanced genetic testing. Emerging treatments include targeted monoclonal antibodies and small molecules, whereas hematopoietic stem cell transplantation (HSCT) is still a valid option for some specific disorders and may be curative also on atopic manifestations.

SUMMARY

The recognition and accurate diagnosis of IEIwA are crucial for timely and appropriate therapeutic intervention. The diagnosis should be suspected according to the presence of 'red flags' at clinical evaluation stage, such as early-onset severe atopy, recurrent/atypical infections, and autoimmunity. The diagnostic confirmation requires genetic testing. Precision medicine approaches like biological therapies and HSCT seem to provide promising results. It is worth noting that clinical and translational research in the field of IEIwA is currently paving the way for a more thorough understanding of the molecular bases of common allergic diseases.

Inborn Errors of Immunity in Early Childhood: Essential Insights for the Neonatologist

BACKGROUND

Inborn errors of immunity (IEI), formerly referred to as primary immunodeficiencies, manifest with a wide range of symptoms such as increased susceptibility to infections, immune dysregulation, and autoinflammation. Although most cases manifest in childhood, onset during the neonatal period is rare but potentially critical.

SUMMARY

In this review, we discuss the diverse clinical presentations of IEI and the specific challenges they pose to neonatologists. Rather than detailing every molecular defect, we focus on common clinical scenarios in neonates and young infants, providing practical diagnostic strategies to ensure timely and effective therapeutic interventions.

KEY MESSAGES

Clinical presentations of IEI in neonates may include delayed separation of the umbilical cord, skin rashes such as eczema and erythroderma, and recurrent episodes of inflammation. We also highlight immunological emergencies that require urgent medical attention, such as hyperinflammatory activity mimicking acute neonatal liver failure, sometimes seen in hemophagocytic lymphohistiocytosis. We also discuss appropriate medical action in the case of a positive newborn screening for severe T-cell defects. Early medical intervention in such circumstances may significantly improve outcomes.

Staphylococcus aureus Serine protease-like protein A (SplA) induces IL-8 by keratinocytes and synergizes with IL-17A

BACKGROUND

Serine protease-like (Spl) proteins produced by Staphylococcus (S.) aureus have been associated with allergic inflammation. However, effects of Spls on the epidermal immune response have not been investigated.

OBJECTIVES

To assess the epidermal immune response to SplA, SplD and SplE dependent on differentiation of keratinocytes and a Th2 or Th17 cytokine milieu.

METHODS

Human keratinocytes of healthy controls and a STAT3-hyper-IgE syndrome (STAT3-HIES) patient were cultured in different calcium concentrations in the presence of Spls and Th2 or Th17 cytokines. Keratinocyte-specific IL-8 production and concomitant migration of neutrophils were assessed.

RESULTS

SplE and more significantly SplA, induced IL-8 in keratinocytes. Suprabasal-like keratinocytes showed a higher Spl-mediated IL-8 production and neutrophil migration compared to basal-like keratinocytes. Th17 cytokines amplified Spl-mediated IL-8 production, which correlated with neutrophil recruitment. Neutrophil recruitment by keratinocytes of the STAT3-HIES patient was similar to healthy control cells.

CONCLUSION

S. aureus-specific Spl proteases synergized with IL-17A on human keratinocytes with respect to IL-8 release and neutrophil migration, highlighting the importance of keratinocytes and Th17 immunity in barrier function.

How to Prevent Atopic Dermatitis (Eczema) in 2024: Theory and Evidence

Atopic dermatitis (AD) or eczema is a chronic inflammatory skin disease characterized by dry, itchy, and inflamed skin. We review emerging concepts and clinical evidence addressing the pathogenesis and prevention of AD. We examine several interventions ranging from skin barrier enhancement strategies to probiotics, prebiotics, and synbiotics; and conversely, from antimicrobial exposure to vitamin D and omega fatty acid supplementation; breastfeeding and hydrolyzed formula; and house dust mite avoidance and immunotherapy. We appraise the available evidence base within the context of the Grades of Recommendation, Assessment, Development, and Evaluation approach. We also contextualize our findings in relation to concepts relating AD and individual-patient allergic life trajectories versus a linear concept of the atopic march and provide insights into future knowledge gaps and clinical trial design considerations that must be addressed in forthcoming research. Finally, we provide implementation considerations to detect population-level differences in AD risk. Major international efforts are required to provide definitive evidence regarding what works and what does not for preventing AD.

Effect of Mixed Probiotics on Ovalbumin-Induced Atopic Dermatitis in Juvenile Mice

Atopic dermatitis is one of the most common dermatologic problems, especially in children. Given the ability of symbiotic microorganisms in modulating the immune system, probiotics administration has been studied in previous research in the management of atopic dermatitis. However, there are conflicting results between studies. In this study, we aimed to assess the effectiveness of mixed probiotics as a treatment option for atopic dermatitis induced by ovalbumin. BALB/c juvenile mice were classified and divided into the ovalbumin group, mixed probiotic group (ovalbumin + LK), and control group. Except for the control group, all mice were sensitized with ovalbumin to establish a model of atopic dermatitis. The mixed probiotics were given by gavage for 14 days. Mice body weight, skin lesions, skin inflammation, ovalbumin-specific Ig, the number of Treg and CD103+DC, and the expression level of PD-1/PD-L1 were examined. The results showed that mixed probiotics can improve body weight and alleviate skin symptoms. Mixed probiotics reduced serum Th2 inflammatory factors, eosinophils, mast cell degranulation, mast cell count, and the expression of ovalbumin-specific immunoglobulin E/G1 and increased the anti-inflammatory cytokine interleukin-10, Treg cells, CD103+DC cells, and the expression level of PD-1/PD-L1. These findings suggest that mixed probiotics could be a viable treatment option for atopic dermatitis and provide insight into the underlying mechanisms involved.

Novel Genetic and Phenotypic Expansion in Ameliorated PUF60-Related Disorders

Heterozygous variants in the Poly(U) Binding Splicing Factor 60kDa gene (PUF60) have been associated with Verheij syndrome, which has the key features of coloboma, short stature, skeletal abnormalities, developmental delay, palatal abnormalities, and congenital heart and kidney defects. Here, we report five novel patients from unrelated families with PUF60-related disorders exhibiting novel genetic and clinical findings with three truncating variants, one splice-site variant with likely reduced protein expression, and one missense variant. Protein modeling of the patient's missense variant in the PUF60 AlphaFold structure revealed a loss of polar bonds to the surrounding residues. Neurodevelopmental disorders were present in all patients, with variability in speech, motor, cognitive, social-emotional and behavioral features. Novel phenotypic expansions included movement disorders as well as immunological findings with recurrent respiratory, urinary and ear infections, atopic diseases, and skin abnormalities. We discuss the role of PUF60 in immunity with and without infection based on recent organismic and cellular studies. As our five patients showed less-severe phenotypes than classical Verheij syndrome, particularly with the absence of key features such as coloboma or palatal abnormalities, we propose a reclassification as PUF60-related neurodevelopmental disorders with multi-system involvement. These findings will aid in the genetic counseling of patients and families.

S3 guideline Atopic dermatitis: Part 2 - Systemic treatment

The present S3 guideline was created based on the European English-language S3 guideline, with special consideration given to the medical conditions in the German-speaking region, and with additions from the previous German-language version, in accordance with the criteria of the AWMF. This second part of the guideline addresses the systemic therapy of atopic dermatitis (AD). It covers topics such as the indication for systemic therapy in children, adolescents, and adult patients with AD. Furthermore, it addresses all medications approved for AD, such as the biologics dupilumab and tralokinumab, the Janus kinase inhibitors abrocitinib, baricitinib, and upadacitinib, as well as conventional immunosuppressive therapies with systemic glucocorticosteroids and ciclosporin. Additionally, it discusses systemic off-label therapies. The first part of the guideline, published separately, includes the definition and diagnostic aspects of AD, describes topical therapy, non-drug therapy approaches, and addresses aspects related to special patient groups.

S3-Leitlinie Atopische Dermatitis: Teil 2 - Systemische Therapie: S3 guideline Atopic dermatitis: Part 2 - Systemic treatment

Die vorliegende S3‐Leitlinie wurde auf der Basis der europäischen englischsprachigen S3‐Leitlinie unter besonderer Berücksichtigung der medizinischen Gegebenheiten im deutschsprachigen Raum und mit Ergänzungen der deutschsprachigen Vorgängerversion, entsprechend den Kriterien der AWMF, erstellt. Dieser zweite Teil der Leitlinie behandelt die systemische Therapie der atopischen Dermatitis (AD). Eingegangen wird unter anderem auf die Indikationsstellung für eine Systemtherapie bei Kindern, Jugendlichen und erwachsenen Patienten mit AD. Darüber hinaus werden alle für die AD zugelassenen Medikamente wie die Biologika Dupilumab und Tralokinumab, die Januskinase‐Inhibitoren Abrocitinib, Baricitinib und Upadacitinib sowie die konventionellen immunsuppressiven Therapien mit systemischen Glukokortikosteroiden und Ciclosporin adressiert. Systemische Off‐Label‐Therapien werden ebenfalls behandelt. Der separat publizierte erste Teil der Leitlinie umfasst die Definition und diagnostischen Aspekte der AD, beschreibt die topische Therapie sowie nichtmedikamentöse Therapieverfahren und geht auf Aspekte bei besonderen Patientengruppen ein.

Elevated IgE Levels-An Allergy or an Underlying Inborn Error of Immunity in Children with Recurrent Infections?

Elevated immunoglobulin E (IgE) is a hallmark of allergic diseases. However, high IgE levels also occur in a number of other infectious and noninfectious diseases. In most cases, elevated IgE levels indicate allergy, eczema, or chronic skin infection. Very high IgE levels are not uncommon in patients with active eczema but more often indicate monogenic atopic disorder or inborn errors of immunity with an atopic phenotype. We conducted a retrospective study of 385 children with suspected immune deficiency referred to the clinic over a 9-year period. Measurement of IgE, IgG, IgA, IgM, and IgG subclasses in blood samples revealed that nearly one-third of the patients had elevated serum IgE levels. Most of the cases with elevated IgE were children with underlying atopy-mainly atopic dermatitis and, to a lesser extent, bronchial asthma-whereas 40.12% (37 children) had no atopy at all. In the most severe cases (with extremely elevated IgE or severe dermatitis), we confirmed genetic mutations for underlying immunodeficiency. Our results indicate that allergic phenotype should not be underestimated and that children with more severe allergic disease should be evaluated for an underlying inborn error of immunity. If inborn error of immunity (IEI) is suspected, a comprehensive immunologic evaluation is required. Genetic testing helps identify the specific genetic abnormality, which provides important insight into the immunopathogenesis of the disease and accurate determination of optimal therapy.

Atypical Localization of Eczema Discriminates DOCK8 or STAT3 Deficiencies from Atopic Dermatitis

PURPOSE

Autosomal recessive dedicator of cytokinesis 8 (DOCK8-/-) and autosomal dominant signal transducer and activator of transcription 3 (STAT3-/+) deficiencies are inborn errors of immunity (IEI) disorders present with the classic features of eczema and create a dilemma during differentiation from atopic dermatitis (AD). Therefore, an appropriate approach is required for eczema to diagnose DOCK8-/- and STAT3-/+ early. Here, we described a set of clinical and immunological variables, including atypical AD localizations and lymphocyte subsets, to differentiate DOCK8-/- or STAT3-/+ from AD.

METHODS

This multicenter study involved 100 patients with DOCK8-/- and STAT3-/+ and moderate/severe AD. We recruited disease manifestations, including detailed localizations of eczema, infections, and allergy. Principle component analysis (PCA) was used to discriminate DOCK8-/- or STAT3-/+ from AD.

RESULTS

There were 43 patients with DOCK8-/-, 23 with STAT3-/+, and 34 with AD. Pneumonia, severe infections, mucocutaneous candidiasis, and skin abscesses were commonly observed in DOCK8 and STAT3 deficiencies. Atypical skin involvement with neonatal rash, retro auricular, axillary, sacral, and genital eczema discriminate DOCK8-/- and STAT3-/+ from AD with high specificity ranges between 73.5 and 94.1% and positive predictive index ranges between 55 and 93.1%. Together with using absolute numbers of CD3+, CD4+, and CD8+ T cells, the combined clinical and laboratory features showed perfect differentiation between DOCK8-/- or STAT3-/+ and AD via PCA.

CONCLUSIONS

The described features can be easily implemented by physicians providing early diagnosis of DOCK8 and STAT3 deficiencies.

STAT6 gain-of-function variant exacerbates multiple allergic symptoms

BACKGROUND

Allergic diseases were long considered to be complex multifactorial disorders. However, recent findings indicate that severe allergic inflammation can be caused by monogenic immune defects.

OBJECTIVES

We sought to clarify the molecular pathogenesis of a patient with early-onset multiple allergic diseases, a high serum IgE level, hypereosinophilia, treatment-resistant severe atopic dermatitis with increased dermal collagen fiber deposition, and eosinophilic gastrointestinal disorder with numerous polypoid nodules.

METHODS

A missense variant in STAT6 was identified, and its function was examined using peripheral blood, transfected HEK293 cells, lymphoblastoid cell lines, and knock-in mice with the corresponding mutation.

RESULTS

Whole-exome sequencing identified a de novo heterozygous missense variant in signal transducer and activator of transcription 6 (STAT6) (p.Asp419Asn). Luciferase reporter assay revealed that the transcriptional activity of this STAT6 mutant was upregulated even without IL-4 stimulation. Phosphorylation of STAT6 was not observed in either the patient's T_H2 cells or lymphoblastoid cell lines without stimulation, whereas it was induced more strongly in both by IL-4 stimulation compared with healthy controls. STAT6 protein was present in the nuclear fraction of the lymphoblastoid cell lines of the patient even in the absence of IL-4 stimulation. The patient's gastric mucosa showed upregulation of STAT6-, fibrosis-, and germinal center formation-related molecules. Some of the knock-in mice with the corresponding mutation spontaneously developed dermatitis with skin thickening and eosinophil infiltration. Moreover, serum IgE levels and mRNA expression of type 2 cytokines were increased in the knock-in mice-with or without development of spontaneous dermatitis-compared with the wild-type mice.

CONCLUSIONS

A novel STAT6 gain-of-function variant is a potential cause of primary atopic disorders.

Atopic Dermatitis-like Genodermatosis: Disease Diagnosis and Management

Eczema is a classical characteristic not only in atopic dermatitis but also in various genodermatosis. Patients suffering from primary immunodeficiency diseases such as hyper-immunoglobulin E syndromes, Wiskott-Aldrich syndrome, immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome, STAT5B deficiency, Omenn syndrome, atypical complete DiGeorge syndrome; metabolic disorders such as acrodermatitis enteropathy, multiple carboxylase deficiency, prolidase deficiency; and other rare syndromes like severe dermatitis, multiple allergies and metabolic wasting syndrome, Netherton syndrome, and peeling skin syndrome frequently perform with eczema-like lesions. These genodermatosis may be misguided in the context of eczematous phenotype. Misdiagnosis of severe disorders unavoidably affects appropriate treatment and leads to irreversible outcomes for patients, which underlines the importance of molecular diagnosis and genetic analysis. Here we conclude clinical manifestations, molecular mechanism, diagnosis and management of several eczema-related genodermatosis and provide accessible advice to physicians.

European guideline (EuroGuiDerm) on atopic eczema: part I - systemic therapy

The evidence- and consensus-based guideline on atopic eczema was developed in accordance with the EuroGuiDerm Guideline and Consensus Statement Development Manual. Four consensus conferences were held between December 2020 and July 2021. Twenty-nine experts (including clinicians and patient representatives) from 12 European countries participated. This first part of the guideline includes general information on its scope and purpose, the health questions covered, target users and a methods section. It also provides guidance on which patients should be treated with systemic therapies, as well as recommendations and detailed information on each systemic drug. The systemic treatment options discussed in the guideline comprise conventional immunosuppressive drugs (azathioprine, ciclosporin, glucocorticosteroids, methotrexate and mycophenolate mofetil), biologics (dupilumab, lebrikizumab, nemolizumab, omalizumab and tralokinumab) and janus kinase inhibitors (abrocitinib, baricitinib and upadacitinib). Part two of the guideline will address avoidance of provocation factors, dietary interventions, immunotherapy, complementary medicine, educational interventions, occupational and psychodermatological aspects, patient perspective and considerations for paediatric, adolescent, pregnant and breastfeeding patients.

Diagnosis and clinical management of Wiskott-Aldrich syndrome: current and emerging techniques

INTRODUCTION

Wiskott-Aldrich syndrome (WAS) serves as the prototype of how variants in a gene which encodes a protein central to actin cytoskeletal homeostasis can manifest clinically in a variety of ways including infection, atopy, autoimmunity, inflammation, bleeding, neutropenia, non-malignant lymphoproliferation, and malignancy. Despite the discovery of the WAS gene almost 30 years ago, our understanding of the pathophysiological mechanisms underlying WAS continues to unfold.

AREAS COVERED

This review will provide an overview of the approach to the diagnosis of WAS as well as the management of its associated complications. Advances in the use of allogeneic hematopoietic stem cell transplantation (HSCT) and gene therapy as well as the associated challenges unique to WAS will be discussed.

EXPERT OPINION

Basic research, combined with clinical research focusing on longitudinal analysis of WAS patients, will help clarify determinants that influence WAS pathogenesis as well as clinical complications and outcomes. Advances in curative approaches including the use of alternative donor HSCT for WAS continue to evolve. Gene therapy employing safer and more effective protocols ensuring full correction of WAS will provide life-saving benefit to WAS patients that are unable to undergo HSCT.

Very Elevated IgE, Atopy, and Severe Infection: A Genomics-Based Diagnostic Approach to a Spectrum of Diseases

Elevated IgE has been long recognized as an important clinical marker of atopy but can be seen in a myriad of conditions. The discovery of autosomal dominant STAT3 deficiency marked the first recognition of hyper-IgE syndrome (HIES) and the first primary immunodeficiency linked to elevated IgE. Since then, genomic testing has increased the number of defects with associated mutations causing hyper-IgE syndrome and atopic diseases with FLG, DOCK8, SPINK5, and CARD11, among others. A spectrum of recurrent infections and atopy are hallmarks of elevated IgE with significant phenotypic overlap between each underlying condition. As treatment is predicated on early diagnosis, genomic testing is becoming a more commonly used diagnostic tool. We present a 6-year-old male patient with markedly elevated IgE and severe atopic dermatitis presenting with staphylococcal bacteremia found to have a heterozygous variant in FLG (p.S3247X) and multiple variants of unknown significance in BCL11B, ZAP70, LYST, and PTPRC. We review the genetic defects underpinning elevated IgE and highlight the spectrum of atopy and immunodeficiency seen in patients with underlying mutations. Although no one mutation is completely causative of the constellation of symptoms in this patient, we suggest the synergism of these variants is an impetus of disease.