Human germline heterozygous gain-of-function STAT6 variants cause severe allergic disease

STAT6 (signal transducer and activator of transcription 6) is a transcription factor that plays a central role in the pathophysiology of allergic inflammation. We have identified 16 patients from 10 families spanning three continents with a profound phenotype of early-life onset allergic immune dysregulation, widespread treatment-resistant atopic dermatitis, hypereosinophilia with esosinophilic gastrointestinal disease, asthma, elevated serum IgE, IgE-mediated food allergies, and anaphylaxis. The cases were either sporadic (seven kindreds) or followed an autosomal dominant inheritance pattern (three kindreds). All patients carried monoallelic rare variants in STAT6 and functional studies established their gain-of-function (GOF) phenotype with sustained STAT6 phosphorylation, increased STAT6 target gene expression, and TH2 skewing. Precision treatment with the anti-IL-4Rα antibody, dupilumab, was highly effective improving both clinical manifestations and immunological biomarkers. This study identifies heterozygous GOF variants in STAT6 as a novel autosomal dominant allergic disorder. We anticipate that our discovery of multiple kindreds with germline STAT6 GOF variants will facilitate the recognition of more affected individuals and the full definition of this new primary atopic disorder

A Solve-RD ClinVar-based reanalysis of 1522 index cases from ERN-ITHACA reveals common pitfalls and misinterpretations in exome sequencing

Purpose Within the Solve-RD project (https://solve-rd.eu/), the European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies aimed to investigate whether a reanalysis of exomes from unsolved cases based on ClinVar annotations could establish additional diagnoses. We present the results of the “ClinVar low-hanging fruit” reanalysis, reasons for the failure of previous analyses, and lessons learned. Methods Data from the first 3576 exomes (1522 probands and 2054 relatives) collected from European Reference Network for Intellectual disability, TeleHealth, Autism and Congenital Anomalies was reanalyzed by the Solve-RD consortium by evaluating for the presence of single-nucleotide variant, and small insertions and deletions already reported as (likely) pathogenic in ClinVar. Variants were filtered according to frequency, genotype, and mode of inheritance and reinterpreted. Results We identified causal variants in 59 cases (3.9%), 50 of them also raised by other approaches and 9 leading to new diagnoses, highlighting interpretation challenges: variants in genes not known to be involved in human disease at the time of the first analysis, misleading genotypes, or variants undetected by local pipelines (variants in off-target regions, low quality filters, low allelic balance, or high frequency). Conclusion The “ClinVar low-hanging fruit” analysis represents an effective, fast, and easy approach to recover causal variants from exome sequencing data, herewith contributing to the reduction of the diagnostic deadlock

Hematochezia caused by eosinophilic proctocolitis in a newborn before oral feeding: a case report

Abstract Background Hematochezia is a frequent symptom in early infancy. However, it occurs very rarely within the immediate neonatal period, and its occurrence before any oral intake is particularly rare. Because of the “congenital” presentation of hematochezia in our patient, we initially considered our case to be a non-classical, potentially severe type of food protein-induced allergic proctocolitis. This diagnosis needs to be confirmed by an abnormal oral challenge test once the hematochezia has disappeared. If such a challenge cannot demonstrate an allergic origin, then the etiology of the hematochezia could be a neonatal transient eosinophilic colitis. Only two similar cases have been described so far. Case presentation We report the case of a black baby boy of African origin born at 36 weeks 5 days of gestational age who presented with massive hematochezia immediately after birth. A rectosigmoidoscopy revealed a severe inflammation associated with diffuse eosinophilic infiltration on biopsy. His clinical outcome was favorable after introduction of an amino acid formula diet. We initially considered our case to be a non-classical, potentially severe type of food protein-induced allergic proctocolitis but reintroduction of standard formula milk at the age of 3 months was successful. So, our patient is the first newborn in Europe who fits the diagnosis of “neonatal transient eosinophilic colitis.” Conclusions We discuss the possible etiology of “congenital” eosinophilic inflammation of the distal colon and conclude that hematochezia in well-looking neonates, in the absence of negative challenge tests later on, is more likely to be a neonatal transient eosinophilic colitis than an allergic proctocolitis. This new entity could be more frequent than previously thought, changing our medical care strategies for this kind of neonatal symptom

Hepatitis B virus vaccination and revaccination response in children diagnosed with coeliac disease : a multicentre prospective study

Aim : This study evaluates hepatitis B virus (HBV) vaccination response in children with celiac disease (CD). Response in initial non-responders after a single booster vaccination as well as factors influencing HBV vaccination response were evaluated. Methodology : Anti-hepatitis B surface antibodies (a-HBsAB) were checked in all children with CD and a documented complete HBV vaccination. An a-HBsAB <10 U/L was considered as non-response. A single intramuscular HBV-vaccine booster was advised to all non-responders. Response was checked at the next appointment. Results : 133 children with CD were included, median age of 7.3 years (range 1.7-17.3) and 46 (35%) were male. The age at CD diagnosis was 6.0 years (range 1.1-15.7). HBV non-response was documented in 55% (n=73/133). No other factors were influencing the response. A booster was documented in 34/73 (47 %) initial non-responders (3 refused (4%), 36 (49%) had no follow up). Response after booster vaccination resulted in immunity in 22/34 (65%) and persisting non-response in 12/34 (35%). A single booster is able to reduce non-response from 55% (73/133) to 23% (22/94). Conclusion : A significantly lower immune response following HBV vaccination in children with CD was confirmed. A single intramuscular booster vaccination is able to induce a serologic response in two thirds of the initial non-responders. Control of HBV vaccination response has to become part of the follow-up in CD patients

Integrated gut metabolome and microbiome fingerprinting reveals that dysbiosis precedes allergic inflammation in IgE-mediated pediatric cow's milk allergy

BackgroundIgE-mediated cow's milk allergy (IgE-CMA) is one of the first allergies to arise in early childhood and may result from exposure to various milk allergens, of which β-lactoglobulin (BLG) and casein are the most important. Understanding the underlying mechanisms behind IgE-CMA is imperative for the discovery of novel biomarkers and the design of innovative treatment and prevention strategies.MethodsWe report a longitudinal in vivo murine model, in which two mice strains (BALB/c and C57Bl/6) were sensitized to BLG using either cholera toxin or an oil emulsion (n = 6 per group). After sensitization, mice were challenged orally, their clinical signs monitored, antibody (IgE and IgG1) and cytokine levels (IL-4 and IFN-γ) measured, and fecal samples subjected to metabolomics. The results of the murine models were further extrapolated to fecal microbiome-metabolome data from our population of IgE-CMA (n = 22) and healthy (n = 23) children (Trial: NCT04249973), on which polar metabolomics, lipidomics and 16S rRNA metasequencing were performed. In vitro gastrointestinal digestions and multi-omics corroborated the microbial origin of proposed metabolic changes.ResultsDuring mice sensitization, we observed multiple microbially derived metabolic alterations, most importantly bile acid, energy and tryptophan metabolites, that preceded allergic inflammation. We confirmed microbial dysbiosis, and its associated effect on metabolic alterations in our patient cohort, through in vitro digestions and multi-omics, which was accompanied by metabolic signatures of low-grade inflammation.ConclusionOur results indicate that gut dysbiosis precedes allergic inflammation and nurtures a chronic low-grade inflammation in children on elimination diets, opening important new opportunities for future prevention and treatment strategies.</p