Severe RSV infection in infancy is associated with increased risk of recurrent wheezing in childhood. Both acute and long-term alterations in airway functions are thought to be related to inefficient anti-viral immune response. The airway epithelium, the first target of respiratory syncytial virus (RSV), normally acts as an immunological barrier able to elicit an effective immune reaction but may also be programmed to directly promote a Th2 response, independently from Th2 lymphocyte involvement. Recognition of RSV transcripts and viral replication intermediates by bronchial epithelial cells brings about release of TSLP, IL-33, HMGB1 and IL-25, dubbed “alarmins”. These epithelial cell-derived proteins are particularly effective in stimulating innate lymphoid cells 2 (ILC2) to release IL-4, IL-5, and IL-13. ILC2, reflect the innate counterparts of Th2 cells and, when activate, are potent promoters of airway inflammation and hyperresponsiveness in RSV bronchiolitis and childhood wheezing/asthma. Long-term epithelial progenitors or persistent epigenetic modifications of the airway epithelium following RSV infection, may play a pathogenetic role in the short and long-term increased susceptibility to obstructive lung diseases in response to RSV in the young. Additionally, ILC2 function may be further regulated by RSV-induced changes in gut microbiota community composition that can be associated with disease severity in infants. A better understanding of the alarmin-ILC interactions in childhood might provide insights into the mechanisms characterizing these immune-mediated diseases and indicate new targets for prevention and therapeutic interventions.

We describe a case of Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) to multiple CFTR modulators and piperacillin in an 8 year old female with CF. To our knowledge this is the first reported case of delayed type, T-cell mediated hypersensitivity to multiple CFTR modulators described in literature. Our findings suggest possible cross-reactivity between CFTR modulators or multiple sensitisations, which should be taken into account in similar cases.

Background: Previous studies reported controversial results regarding the association between allergic disorders and ADHD/ASD. The aim of this article is to investigate whether allergic disorders are associated with ADHD/ASD in a large cohort of pediatric patients. Methods: A retrospective study using the pediatric (0-18 year) database (ICD-9-CM codes) of Clalit Health Services during the years (2000-2018). Diagnosis of all disorders was made by specialist physicians. Results: 117,022 consecutive non-selective allergic children diagnosed with one or more allergic disorder (asthma, rhinitis. conjunctivitis, skin, food, or drug allergy) and 116,968 non-allergic children were enrolled to our study. The mean follow-up period was 11±6 years. The presence of allergic disorders in early childhood (mean age of allergic diagnosis 4.5± 4.3 years) in boys as well as in girls, significantly increased the risk to develop ADHD (O.R 2.45, CI 2.39-2.51; P<0.0001), ASD (O.R 1.17, CI 1.08-1.27; P<0.0001) or both ADHD+ASD (O.R 1.5, CI 1.35-1.79; P<0.0001). Children with more than one allergic comorbidity revealed a much higher risk. In a multivariable analysis (adjusted for age at study entry, number of yearly visits and gender) the risk of allergic children to develop ADHD and ADHD+ASD, but not ASD alone, remained significantly higher. Conclusion: Allergic disorder in early childhood significantly increased the risk to develop ADHD, and to a less extend ASD, in later life.

Several inborn errors of immunity are caused by defects in the general DNA repair machinery as exemplified by the T-B- RS-SCID condition owing to impaired resolution of programmed DNA double strands breaks introduced by RAG1/2 during V(D)J recombination. The genome instability generally associated with these conditions results in an increased propensity to develop malignancies requiring genotoxic based anti-cancer treatments. Moreover, the extent of immune deficiency often calls for hematopoietic stem cell transplantation as a definitive treatment, thus also demanding genotoxic based conditioning regimen prior to transplantation. In both cases, the underlying general DNA repair defects may result in catastrophic iatrogenic consequences. It is therefore of paramount importance to assess the functionality of the DNA repair apparatus prior to any genotoxic treatment when the exact molecular cause of the disease is unknown. For this purpose, two simple assays can be used on patient’s derived peripheral blood lymphocytes. 1) The PROMIDISα biomarker, based on the next generation sequencing analysis of the TCRα will highlight specific signatures of DNA repair deficiencies. 2) Direct analysis of the sensitivity of peripheral lymphocytes to ionizing radiations will formally identify patients at risk to develop toxicity towards genotoxic based treatments.

Editorial to the special issue “Environmental influences on childhood asthma”Back in 1892, Sir William Osler gave an accurate description of asthma as a disease that is associated with “spasm of the bronchial muscles, inflammation of the smaller bronchioles, bizarre and extraordinary variety of circumstances and cold infections, often running in families (1,2). This is basically a true reflection of our modern understanding of asthma which states that asthma is a complex genetic disorder that involves interactions between genetic and environmental factors.Since the human genetic makeup has not changed significantly in the last couple of decades, there is reason to believe that the overall increase in asthma prevalence (3) can be attributed to the changing environmental conditions of modern life. The role of environment in asthma is not limited to its role in the pathogenesis of the disease. Since it is currently not possible to change the genetic make-up of an individual underlying a complex genetic disorder such as asthma, modification of environmental conditions emerges as a significant tool for its treatment. Therefore, understanding the environmental factors that play an important role in asthma is crucial in understanding the disease pathogenesis as well as modification of factors that modulate the inception and progress of the disease as well as its treatment.Various studies published in the last years in the journal and included in this virtual issue have addressed these questions. Garcia-Serna et al. have found out that gestational exposure to traffic-related air pollutants (TRAP) may increase the pro-inflammatory and Th2-related cytokines in newborns which might influence immune system responses later in life (4). Similarly, Pesce et al. (5) have investigated the association between prenatal exposures to heavy metals and atopic diseases. The serum concentrations of lead, cadmium and manganese were assessed in maternal blood samples collected during pregnancy and in cord blood of 651 mother-children pairs. The authors have concluded that the levels of cadmium in cord blood were associated with greater risk of asthma at the age of 8. Baek et al. have documented that exposure to phthalates are associated with airway dysfunction in childhood and this effect was partially attributable to increased serum periostin levels (6). Regarding the association between the genes and environment, Theodorou et al. (7) have investigated the role of mitogen-activated protein kinase (MAPK) pathway in 232 children who were selected from two cross-sectional cohorts and one birth cohort study. They have isolated peripheral blood mononuclear cells (PBMC) from children with asthma along with healthy controls and stimulated them with farm-dust extracts or lipopolysaccharide. The results have shown that the children with asthma have expressed significantly less dual-specificity phosphatase-1 (DUSP1) which is the negative regulator of MAPK pathway. They have conclusively indicated the possible role of DUSP1 for future therapeutical interventions regarding the anti-inflammatory features of farming environments.In an effort to further elucidate the environmental factors that are central to our understanding of asthma, the journal has started a review series to provide a comprehensive picture on the role of environment on various aspect of asthma. Major subheadings includedBiodiversityUrban exposuresGene-environment interactionsFarm effectAir pollutionClimate changeAllergensDiet microbiome and obesityIn the virtual issue of the journal Tari Haahtela (8) has focused on the effect of biodiversity. Evidence supports that the immunomodulating roles of different micro-organisms may be protective for asthma and allergic diseases. The studies from the neighboring Finnish and Russian Karelia regions, which the author named as “the living laboratory”, have shown strong evidence for the central role of environment and lifestyle which modify the human microbiome, immune balance, and thus allergy and asthma risk. Diversity of the human microbiome as well as the diversity of the natural environment that we live in and more contact with the nature are important determinants of physical health.Grant et al. (9) have focused on the influence of urban exposures on childhood asthma. The authors have meticulously summarized and analyzed the results of previous studies which aimed to investigate the interaction between indoor allergens, microbes, indoor and outdoor pollutants, social determinants and childhood asthma along with the opportunities for intervention. Multiple environmental exposures and influences contribute to the increased incidence of asthma and excess asthma morbidity among children with asthma living in urban communities. Indoor pest allergen and mold exposures have been repeatedly linked to increased asthma diagnosis, symptoms, and exacerbations in urban children. However, studies in high-risk urban populations also found that early life pest allergen exposure, along with microbial and endotoxin exposure may be associated with a decreased risk of wheezing and asthma suggesting that the association is more complex than previously thought.Since asthma prevalence varies widely depending on the socio-economical level, changes to help reduce inequities and inequalities in social determinants of health such as poverty, housing disrepair, higher rates of obesity, and chronic stress may produce positive effects at the population-level.Hernandez-Pacheco et al (10) have reviewed the latest gene-environment interaction (GxE) studies in childhood asthma. They have summarized the role of various environmental exposures and the current state of knowledge on asthma genetics. The field of GxE in asthma has drastically evolved together with technological advances over the last years. However, despite reports on the effect of numerous environmental factors on childhood asthma, the availability of detailed and diverse exposure data is limited. Tobacco smoke remains to be the most accessible and extensively explored factor followed by traffic-related air pollution in GxE studies.Airway epithelium seems to be central in gene-environment interactions. The effect of the exposure to certain environmental factors early in life on the modification of the risk and severity of asthma later in childhood is partially dependent on the functionality and integrity of the airway epithelium. It is known that the environmental exposures can trigger an inflammatory response and the disruption of the barrier and mucociliary function.Although there are several methodological and conceptual challenges with GxE interaction studies, recent data have led to new insights into childhood asthma pathophysiology which is best exemplified by the 17q12-21 asthma locus. Some of the SNPs at this locus seem to be associated with the onset of childhood asthma, thereby highlighting the importance of age related factors in gene environment interactions.The need for longitudinal and functional studies which provide insights into the biological mechanisms underlying the observed associations between environmental exposures and epigenetic changes that modify the asthma risk is highlighted.Another extensively studied environmental factor that is associated with childhood as is the so called “farm effect”. Frei et al. (11) have summarized the current knowledge on how “farm effect” influences the immune homeostasis during the intrauterine period and in childhood with a focus on immune mechanisms induced by environmental microbial diversity and microbial components. Farming lifestyle factors including nutrition influence the immune homeostasis either by regulating the innate immune system or by induction of regulatory T cells or TH1. We see diversity as a significant factor also in the farm effect. Diversity of environmental microbes, the diversity of the gut microbiome, or the diversity of the nutrition emerge as significant factors.Paciencia et al. (12) investigated the association and mechanisms between air pollution and asthma in children along with the precautions that should be taken to reduce the burden of air pollution on asthma. Environmental conditions are not shared equally across the populations, regions, and settings where people live, work, and spend their time. Urban conditions and air quality are not only important features for national and local authorities to shape healthy cities and protect their citizens from environmental and health risks, but they also provide opportunities to mitigate inequalities in the most deprived areas where the environmental burden is highest. Actions to avoid exposure to indoor and outdoor air pollutants should be complementary at different levels –individual, local, and national levels – to take strong measures to protect children.Taken together, these reviews provide a very comprehensive coverage on the role of environmental factors on childhood asthma and suggest that efforts to modify these factors may have beneficial effects not only on the individual level but also at the population level.S. Tolga Yavuz1Ömer Kalayci2Philippe A. Eigenmann3

Threshold and safe ingestion dose among infants sensitized to hen’s eggMasatoshi Mitomori,a Noriyuki Yanagida,aMakoto Nishino,a Kyohei Takahashi,aKen-ichi Nagakura,a Kiyotake Ogura,aMari Takei,b Sakura Sato,b Motohiro EbisawabaDepartment of Pediatrics, National Hospital Organization, Sagamihara National Hospital, Kanagawa, JapanbClinical Research Center for Allergy and Rheumatology, National Hospital Organization, Sagamihara National Hospital, Kanagawa, JapanRunning title: Threshold and safe ingestion dose of egg

Background: Cross-reactivity between wheat and other cereals is an essential issue in the management of wheat allergy. Few studies have reported in vitro cross-reactivity in immediate-type wheat allergy. This study aimed to examine cross-reactivity of the three fractions (albumin/globulin, gliadin, and glutenin fractions) among cereals in children with wheat allergy. Methods: Sera from 128 children with immediate-type wheat allergy were collected. We measured specific immunoglobulin E (sIgE) levels against each fraction of wheat, barley, and rye by using an enzyme-linked immunosorbent assay (ELISA). Cross-reactivities of each fraction among wheat, barley, and rye were examined via inhibition ELISA. Results: All subjects were sensitized to all the fractions of wheat, and also those of barley and rye. The wheat sIgE levels were significantly higher than those of barley and rye in all the fractions (p ≤ 0.001) and were significantly correlated with sIgE levels to them in each fraction (r = 0.887–0.969, p < 0.001). On inhibition ELISA, wheat inhibited the IgE binding to most of the solid phases at the lower protein levels compared to barley and rye in all fractions. Conclusions: In children with immediate-type wheat allergy, sensitization to all the three fractions of wheat was observed. In addition, they showed sensitization to barley and rye caused by in vitro cross-reactivity with wheat in each fraction. When managing children with wheat allergy, sensitization to barley and rye caused by the cross-reactivities should be considered.

Background: In the absence of a clear clinical history of reaction, diagnosis of cashew allergy using skin prick tests (SPT) or cashew-specific IgE requires a high number of oral food challenges (OFC). By using Ana o 3 sIgE alone, or a two-step diagnostic algorithm using cashew sIgE followed by Ana o 3 sIgE, there is a reduced need for OFC. We aimed to perform a cost comparison for both of these approaches compared to cashew SPT alone. Methods: Pooled individual level data from 6 studies was used to determine diagnostic accuracy and OFC rate. Two studies used cashew SPT (n=567, 198 allergic), with 95% positive and negative predictive values of ≥12mm and <3mm. Four studies were included in the pathways for Ana o 3 sIgE alone or a 2-step algorithm incorporating cashew and Ana o 3 sIgE (n=271, 156 allergic). Cut-offs used were ≥8.5kUA/L and ≤0.1kUA/L for cashew sIgE and ≥0.35kUA/L and ≤0.1kUA/L for Ana o 3 sIgE. Costs were constructed based on unit prices from hospital inpatient admissions, expenses incurred by families, individual patient data on allergic reaction types and rates and adrenaline autoinjector carriage, applying a health system perspective. Results: Modelled data through the Ana o 3 pathway resulted in a 46.43% cost reduction (\euro307,406/1000 patients) compared to using cashew SPT alone (\euro573,854/1000 patients). The 2-step algorithm resulted in a 44.94% cost reduction compared to SPT alone (\euro315,952.82/1000 patients). Both the Ana o 3 pathway and 2-step algorithm resulted in a 79-80% reduction in OFCs compared to SPT. Conclusions: Using Ana o 3 as a standalone test for cashew allergy diagnosis or a 2-step algorithm incorporating cashew sIgE and Ana o 3 sIgE is accurate and results in a large reduction in both OFCs and health system costs compared to cashew SPT alone.

Race is a Modifier between Parental Allergy and Food Allergy in OffspringAmy A. Eapen, MD, MS*1, Erica Ridley MD*1, Alexandra R. Sitarik MS2, Christine Joseph PhD2, Christian Nageotte, MD1, Rana Misiak, MD1, Dennis Ownby MD3, Christine Johnson PhD2, Edward Zoratti MD1, Haejin Kim MD1.1Division of Allergy and Clinical Immunology, Henry Ford Health System, Detroit, Michigan2Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan3Department of Pediatrics, Augusta University, Augusta, Georgia.*Dr. Eapen and Dr. Ridley are listed as co-first authorsCorresponding author: Amy A. Eapen, MD, One Ford Place, 4B Detroit, MI 48202; Telephone (313) 971-6182; Fax (313) 876-2094; E-mail: aeapen1@hfhs.orgFunding: Grants from the National Institute of Allergy and Infectious Diseases (R01 A1051598 and P01 A1089473) and the Fund for Henry Ford Hospital.Financial disclosure : There are no financial disclosures of conflicts of interest.Word count: 1191Keywords : Food allergy, race, parental allergy, total IgETo the Editor,Studies indicate associations between maternal allergy and development of food allergy in their offspring1, with higher food allergy risk among those with more than one first degree relative with allergic disease2. However, unnecessary food avoidance among children of allergic parents has important implications since diverse diets in children may decrease risk for food allergy, and early food introduction with foods such as peanut, can be protective for food allergy3. We sought to assess the association between parental allergic markers and offspring food sensitization and clinical allergy to milk, egg, or peanut.We analyzed data from the racially and socioeconomically diverse population birth cohort, Wayne County Health, Environment, Allergy and Asthma Longitudinal Study (WHEALS) that enrolled pregnant women between 21 to 45 years of age and their offspring following recruitment between September 2003 to December 2007. Details regarding the cohort have been previously published4,5. Institutional Review Board (IRB) approval was obtained for all aspects of the study.Parental factors assessed included questionnaire responses regarding history of allergy or asthma; maternal total IgE and maternal serum allergen specific IgE (sIgE) levels during pregnancy or one month postpartum were also evaluated. Atopy was defined as at least one sIgE ≥ 0.35 IU/mL to eight allergens (dust mite, dog, cat, grass, ragweed,Alternaria , egg, cockroach). Maternal asthma, atopic dermatitis, and food allergy were determined by questionnaire. Due to a paucity of paternal data, only paternal asthma was assessed.Offspring sensitization to milk, egg, or peanut was determined at 2 years of age by sIgE≥ 0.35 IU/mL and also skin prick testing (SPT; wheal size ≥3 mm larger than the saline control defined a positive test). As sensitization to foods does not translate to clinical allergy in all cases, we formed an algorithm to determine those most likely to have true IgE-mediated food allergy6. A consensus panel of allergists determined food allergy status in offspring based on review of the aforementioned data and abstracted chart informations as previously described7. Briefly, infant data were forwarded to the panel only if more than one of the following criteria were met for milk, egg, or peanut allergens: (1) 1 sIgE ≥0.35 IU/mL; (2) a positive SPT; or (3) parental report of infant symptoms potentially related to food allergy plus at least one specific IgE greater than 0.10 IU/mL. To enhance standardization in classifying infants to the presence of IgE- mediated food allergy (IgE-FA), physicians were asked to combine professional experience with investigator-developed protocols based on the Guidelines for the Diagnosis and Management of Food Allergy in the United States8. A third allergist independently reviewed and ruled on discordant decisions.Logistic regression models of parental variables with each outcome were fit. Interaction terms were added to logistic regression models to assess differences in associations based on race, (p<0.10 was considered a significant interaction). Predicted probabilities were used to construct receiver operating characteristic (ROC) curves and calculate area-under-the-curve (AUC) values.Of 1258 maternal-child pairs, 761 had sufficient data for analysis (Supplemental Figure el). Participant characteristics indicated that families not lost to follow up had higher household incomes, as well as higher maternal education, and a higher proportion of mothers who were married, kept pets, and breastfed the child. rates (Table e1).Associations between parental variables and physician panel determination of food allergy are shown in Table 1. After adjusting for child race, seven out of eight parental characterics of the were significant or of borderline signficance. However, the maximum AUC for ROC curves for any individual variable was 0.54 (maternal total IgE), indicating poor prognostic value (Supplemental Table e2). Maternal atopy, multi-sensitization, and total IgE significantly interacted with race (p=0.012, 0.092, 0.068, respectively) indicating strong associations among African American (AA) children only (Table 1). For example, maternal atopy in non-AA children was not associated with food allergy, but was highly associated among AA children (OR [95% CI]=3.56 [1.55, 9.66], p=0.006).Maternal current asthma was also associated with childhood food allergy (OR [95% CI]=2.27 [1.02, 4.71], p=0.034), and patterns varied by race with history of maternal asthma associated with food allergy only in non-AA children (OR [95% CI]= 4.92 [1.22, 17.14], p=0.015), and current asthma among AA children (OR [95% CI]=2.64 [1.10, 5.92], p=0.022; Table 1).Combined, parental variables only modestly impacted food allergy ROC analyses resulting in an AUC of 0.66. However, the ROC curves differed by race (non-AA AUC 0.36 vs AA AUC 0.71, p=0.002) as shown in Figure 1.Apart from food allergy, parental variables were analysed for associations with offspring sensitization (positive sIgE or SPT) to peanut, milk, or egg at age 2 years. Maternal atopy, multi-sensitization, and total IgE were associated with offspring positive food sIgE sensitization to at least one food. Analysis stratified by race indicated these associations were significant only among AA children. (Supplemental Table e3). Furthermore, maternal current asthma was associated with food sIgE sensitization only among non-AA children (OR [95% CI]=4.90 [1.69, 16.20], p=0.005). ROC curves were significantly different between AA and non-AA children (p=0.036) but predictive ability remained poor in both (AUC 0.55 and 0.44 respectively as in supplemental Figure e2).Maternal multisensitization, total IgE and current asthma, and paternal asthma were statistically significantly associated with any positive food SPTs only among AA children. (Supplemental Table e4). Additionally, race modified the relationship between maternal atopy and SPTs (p=0.039); AA children of atopic mothers had elevated odds of food SPT positivity (OR [95% CI]=1.96 [1.15, 3.45], p=0.016). Despite ROC differences by race (p=0.015; Figure e3), parental variables again had minimal predictive ability.The importance of genetic factors in food allergy is supported by twin studies showing higher concordance of peanut allergy among monozygotic compared with dizygotic twins (64.3% and 6.8%, respectively)9. In addition, heritability among parents and offspring for overall food sensitization have been reported1. However, our report indicates parental variables related to allergy have poor predictive ability for offspring food sensitization. The results from the physician panel demonstrate a moderate degree of risk and capability of predicting food allergy in offspring from parents having clinical characteristics of allergy.We previously reported similar food allergy prevalence for milk, egg, and peanut in AA and non-AA children7. We report here that the inherited risk as measures by parental allergic variables and predictive ability of parental allergic variables on food allergy development in offspring varies by race and is more strongly associated with clinical food allergy versus sensitization, among AA children. The potential mechanisms behind this racial discrepancy are require further studies.Potential study limitations include the physician panel to determine clinical food allergy status as opposed to performing oral food challenges. These challenges are time consuming and impractical to implement in large epidemiological studies10. Another limitation is that non-AA children included multiple ethnicites, which was done to preserve sample size. These groups may have different incidences of disease, and risk may vary. Finally, included and excluded WHEALS participants differed by demographic variables, so findings may not be generalizable to the target population.Parental allergy and atopy, although associated with offspring food allergy, is only a weak predictor and depends upon race. Further studies of familial factors contributing to food allergy and these disparities are needed to precisely identify children at risk for food allergy.Amy A. Eapen, MD, MS*1, Erica Ridley MD*1, Alexandra R. Sitarik MS2, Christine Joseph PhD2, Christian Nageotte, MD1, Rana Misiak, MD1, Dennis Ownby MD3, Christine Johnson PhD2, Edward Zoratti MD1, Haejin Kim MD1.1Division of Allergy and Clinical Immunology2Department of Public Health Sciences, Henry Ford Health System, Detroit, Michigan3Department of Pediatrics, Augusta University, Augusta, Georgia.*Dr. Eapen and Dr. Ridley are listed as co-first authors

Background: Food allergy is a disease with a diverse and variable natural history, and some patients may react to two or more food antigens. This study aimed to classify and characterize the long-term prognosis of infantile-onset, immediate-type food allergies in children, focusing on three major antigens in Japan: egg, milk, and wheat. Methods: All children visited to our hospital with food allergies, including suspected cases, were prospectively registered in our medical database. From this database, infants who had immediate-type symptoms or were sensitized to above three antigens were included. Cox regression analysis and repeated-measures latent class analysis were performed to reveal risk factors and tolerance patterns for food allergies. Results: Of 2,830 patients registered in the database, we included 915 patients with immediate-type food allergy symptoms and 276 sensitized asymptomatic patients in this study. The number of patients with immediate-type symptoms to egg, milk, and wheat was 609, 443, and 235, respectively. The number of patients with multiple food allergies was 302. Ratios of acquiring tolerance to egg, milk, and wheat at the age of 6 years were 74%, 69%, and 75%, respectively. Latent class analysis revealed 10 classes of prognosis for food allergies, including five with multiple food allergies. The largest class was transient egg allergy alone (21.4%), and there were severe cases of persistent allergy to three major allergens (3.2%). Conclusions: This study demonstrated the prognosis of food-allergy classes in Japan, including multiple food allergies, with 10 classes with its own characteristics.

Allergic sensitization without detectable specific serum IgE

Multisystem inflammatory syndrome in children (MIS-C) is a rare, but severe complication of coronavirus disease 2019 (COVID-19). It develops approximately four weeks after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and involves hyperinflammation with multisystem injury, commonly progressing to shock. The exact pathomechanism of MIS-C is not known, but immunological dysregulation leading to cytokine storm plays a central role. In response to the emergence of MIS-C, the European Academy of Allergy and Clinical Immunology (EAACI) established a task force (TF) within the Immunology Section in May 2021. With the use of an online Delphi process, TF formulated clinical statements regarding immunological background of MIS-C, diagnosis, treatment, follow-up, and the role of COVID-19 vaccinations. MIS-C case definition is broad, and diagnosis is made based on clinical presentation. The immunological mechanism leading to MIS-C is unclear and depends on activating multiple pathways leading to hyperinflammation. Current management of MIS-C relies on supportive care in combination with immunosuppressive and/or immunomodulatory agents. The most frequently used agents are systemic steroids and intravenous immunoglobulin. Despite good overall short-term outcome, MIS-C patients should be followed-up at regular intervals after discharge, focusing on cardiac disease, organ damage, and inflammatory activity. COVID-19 vaccination is a safe and effective measure to prevent MIS-C. In anticipation of further research, we propose a convenient and clinically practical algorithm for managing MIS-C developed by the Immunology Section of the EAACI.

Editorial Comment on: „Short-acting β 2 -agonist use and asthma exacerbations in Swedish children: A SABINA Junior study.”Boccabella C. 1, Kalayci O. 2, Eigenmann P. 3Affiliations1Department of Cardiovascular and Thoracic Sciences, Fondazione Policlinico Universitario “A Gemelli” - IRCCS, University of the Sacred Heart, Rome, Italy2Pediatric Allergy and Asthma Unit, Hacettepe University School of Medicine, Ankara, Turkey3Pediatric Allergy Unit, Department of Women-Children-Teenagers, University Hospitals of Geneva, Geneva, SwitzerlandAsthma is one of the most common chronic lung diseases with major public health consequences for both children and adults, including high morbidity and even mortality (1). For years, standard asthma treatment for mild asthma has been as needed short acting beta agonist (SABA). Global Initiative for Asthma (GINA) guidelines have questioned this approach suggesting that the use of SABAs should always be accompanied by inhaled corticosteroids (ICSs) (2). Recently, Papi et al. have shown that in adolescents and adults with uncontrolled moderate-to-severe asthma receiving inhaled glucocorticoid-containing maintenance therapies, the risk of severe asthma exacerbation was significantly lower with as-needed use of a fixed-dose combination of albuterol and budesonide than with as-needed use of albuterol alone (3). In children, on the other hand, even though many years ago Martinez et al. have shown that inhaled corticosteroids as rescue medication with albuterol might be an effective step-down strategy for children aged 5-18 years with well controlled mild asthma , SABA has remained to be the only reliever option recommended for those under 6 years of age (4).The SABA use IN Asthma (SABINA) program in adults and adolescents with asthma reported that SABA overuse (≥3 canisters/year) is prevalent in Sweden and is associated with poor asthma-related outcomes (5). Melen et al and the SABINA Junior investigators have attempted to investigate the same question in the paediatric population (6). This retrospective cohort study conducted in Sweden, has included patients with physician-diagnosed asthma (aged 0-17 years) in secondary care. Patients have been categorized by the number of SABA canisters collected (dichotomized as 0-2 vs ≥3, based on evidence from studies in adults and adolescents) from pharmacies at baseline and followed up over 12 months (5,7). During the baseline year, SABA overuse (≥3 canisters) has been registered for the majority of the study population, particularly for those aged 0-5 years. A strong correlation between SABA overuse and increased risk of exacerbation episodes has been observed. This result confirms what has been already seen among adult patients, that is strongly connected to the inflammatory nature of asthma disease. SABAs can resolve the immediate bronchospasm but have no anti-inflammatory actions and no effect on the late phase of inflammation. Furthermore, chronic and long-term use of SABAs seems also to contribute to a decreased response to SABA therapy as a reliever (8,9). SABINA investigators have also conducted a post-hoc analysis, stratifying study population based on the presence of atopic comorbidity. Interestingly, increased SABA use has been associated with a higher exacerbation risk also in nonatopic patients with asthma. This may be due to the lack of response to ICSs that is a distinctive aspect of non-atopic population who may in turn resort to the use SABA reliever treatment.There are still several questions that remain unanswered in children mainly due to the difficulties in obtaining data in this specific population. First, recruitment of paediatric patients especially those <6 years old into randomized controlled trials (RCTs) can be a challenge due to ethical issues. In addition, diagnosis of asthma in this age group is often problematic. Despite all the limits of a retrospective study, SABINA study provides extremely useful data in a population where there are hardly any solid data. These results emphasize the need for a better understanding of childhood asthma endotypes and the response to different drugs and disease behaviour over time. Avoiding asthma exacerbations and consequent disease progression should be the principal aim of clinical management in children. This may only be possible by linking the underlying pathophysiology with the clinical response to anti-asthma treatment.References1. Asher MI, Rutter CE, Bissell K, Chiang CY, El Sony A, Ellwood E, et al. Worldwide trends in the burden of asthma symptoms in school-aged children: Global Asthma Network Phase I cross-sectional study. Lancet. 2021;398(10311):1569–80.2. GINA committee. Global Strategy for Asthma Management and Prevention 2022 Update [Internet]. Global Initiative for Asthma. 2022. p. 225. Available from: http://www.ginasthma.org3. Alberto Papi, M.D., Bradley E. Chipps, M.D., Richard Beasley, D.Sc., Reynold A. Panettieri, Jr., M.D., Elliot Israel, M.D., Mark Cooper, M.Sc., Lynn Dunsire, M.Sc., Allison Jeynes-Ellis, M.D., Eva Johnsson, M.D., Robert Rees, Ph.D., Christy Cappelletti, P MD. Albuterol–Budesonide Fixed-Dose Combination Rescue Inhaler for Asthma. N Engl J Med [Internet]. 2022 Aug 17;387(7):662–3. Available from: https://doi.org/10.1056/NEJMc22091894. Martinez L, Handel A, Shen Y, Chakraburty S, Quinn FD, Stein CM, et al. detect tuberculosis in child contacts are urgently needed in Sub-Saharan Africa to improve case detection. n. 2018;197(9):2016–9.5. Nwaru BI, Ekström M, Hasvold P, Wiklund F, Telg G, Janson C. Overuse of short-acting β2-agonists in asthma is associated with increased risk of exacerbation and mortality: A nationwide cohort study of the global SABINA programme. Eur Respir J [Internet]. 2020;55(4). 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Introduction: Children with peanut allergy are at increased risk of developing tree nut allergies, which can be severe and for most lifelong. Introduction of peanut in the first year of life can reduce the risk of peanut allergy, however, prevention strategies for tree nut allergies have not been established. We aimed to test the efficacy and safety of a novel strategy, a supervised multi-nut oral food challenge (OFC) compared to standard care for tree nut allergy prevention in infants at high risk of developing tree nut allergy, TreEAT. Methods and analysis: TreEAT is a 2-armed, open-label, randomised, controlled trial (RCT). Infants (n=212) aged 4-11months with peanut allergy will be randomised 1:1 at peanut allergy diagnosis to either a hospital-based multi-tree nut (almond, cashew, hazelnut and walnut) OFC using multi-nut butter or standard care (home introduction of individual tree nuts). All infants will be assessed at age 18months, with questionnaires and SPT to peanut and tree nuts. Peanut and tree nut OFCs will be performed as required to determine allergy status for each nut. The primary outcome is tree nut allergy at age 18 months. Secondary outcomes include peanut allergy resolution, proportion and severity of adverse events related to tree nut ingestion, number and frequency of tree nuts ingested, quality of life and parental anxiety and allergy related healthcare visits from randomisation to 18 months of age. Analyses will be performed on an intention-to-treat basis. Ethics and dissemination TreEAT was approved by the Royal Children’s Hospital Human Research Ethics Committee (#70489). Outcomes will be presented at scientific conferences and disseminated through publication. Trial registration number: ClinicalTrials.gov ID: NCT04801823

Prognosis of infantile food protein-induced enterocolitis syndrome to wheat: A case series Makoto Nishino1,2 | Noriyuki Yanagida1,3,* | Sakura Sato1 | Ken-ichi Nagakura3,4 | Kyohei Takahashi3 |Kiyotake Ogura3| Motohiro Ebisawa11 Clinical Research Center for Allergy and Rheumatology, National Hospital Organization Sagamihara National Hospital, Kanagawa, Japan2 Department of Pediatrics, Ushiku Aiwa General Hospital, Ibaraki, Japan3 Department of Pediatrics, National Hospital Organization Sagamihara National Hospital, Kanagawa, Japan4 Department of Pediatrics, Jikei University School of Medicine, Tokyo, Japan*Corresponding author: Noriyuki YanagidaDepartment of Pediatrics, National Hospital Organization Sagamihara National Hospital,18-1, Sakuradai, Minami-ku, Sagamihara, Kanagawa 252-0392, JapanE-mail:sagami@foodallergy.jpWord count: 1,191Number of figures: 2 Number of tables: 1

BACKGROUND Severe Pediatric Allergic Asthma (SPAA) induces a huge economic burden in terms of direct, indirect and intangible costs. The use of omalizumab for the treatment of these patients has produced a significant improvement in several clinical outcomes, but at the same time, the cost for the management of the disease has also increased. The aim of this report was to evaluate whether the use of omalizumab is cost-effective. METHODS A sample of 426 children with SPAA from the ANCHORS study was used to calculate the Incremental Cost Effectiveness Ratio (ICER) for the avoidance of Moderate to Severe Exacerbations (MSE), and also for the improvement in childhood Asthma Control Test (c-ACT) or the Asthma Control Questionnaire (ACQ5). We retrospectively collected data of health encounters and drug consumption before and up to six years after the beginning of the treatment with omalizumab. RESULTS The ICER per avoided MSE was \euro2,107 after one year, and it consistently decreased to \euro656 in those followed up to six years. Similarly, the ICER for the Minimally Important Difference in control tests showed a decrease from \euro2,059 to \euro380 per each 0.5 points of improvement in ACQ5, and from \euro3,141 to \euro2,322 per each 3 points improvement in c-ACT, at years 1 and 6 respectively. CONCLUSION The use of OMZ is a cost-effective option for most children with uncontrolled SPAA, mainly those who have frequent exacerbations, showing progressively reduced costs in successive years of treatment.

Early childhood allergy prevention behaviours: trends in Germany from 2015 to 2020

Background: Atopic dermatitis (AD) contributes to substantial social and financial costs in public health care systems. Antibiotic exposure during pregnancy has been proposed as a risk factor, but findings remain inconsistent. The aim of this study was to investigate the association between prenatal antibiotic use and childhood AD. Methods: We performed a population-based cohort study using data collected from the Taiwan Maternal and Child Health Database from 2009 to 2016. Associations were determined using Cox proportional hazards model and were adjusted for several potential covariates, including maternal atopic disorders and gestational infections. Subgroup analyses evaluated the influence of postnatal infant antibiotic/acetaminophen use on the association between prenatal antibiotic exposure and childhood AD diagnosed after 1 year of age. Results: A total of 1288343 mother-child pairs were identified and 39.5% received antibiotics prenatally. Maternal antibiotic use during pregnancy was slightly positively associated with childhood AD (aHR 1.05, 95% CI 1.04-1.06), especially in the first and second trimesters. An apparent dose-response pattern was observed with an 11% increased risk when the exposure was ≥5 courses prenatally (aHR 1.11, 95% CI 1.09-1.14). Subgroup analysis showed the positive association remained significant regardless of postnatal antibiotic use; however, a negative association was found in children without postnatal infant acetaminophen use (aHR 1.02, 95% CI 0.97-1.07). Conclusion: Maternal antibiotic use during pregnancy was associated with increased risk of childhood AD in a dose-related manner. Possible confounders existed between prenatal antibiotics and postnatal infant acetaminophen use in the subgroup analysis. Further research may be warranted to investigate this variable using a prospectively designed study, and also to examine whether or not this association is specifically related to pregnancy.