The gut microbiota posttranslationally modifies IgA1 in autoimmune glomerulonephritis

Mechanisms underlying the disruption of self-tolerance in acquired autoimmunity remain unclear. Immunoglobulin A (IgA) nephropathy is an acquired autoimmune disease where deglycosylated IgA1 (IgA subclass 1) auto-antigens are recognized by IgG auto-antibodies, forming immune complexes that are deposited in the kidneys, leading to glomerulonephritis. In the intestinal microbiota of patients with IgA nephropathy, there was increased relative abundance of mucin-degrading bacteria, including Akkermansia muciniphila. IgA1 was deglycosylated by A. muciniphila both in vitro and in the intestinal lumen of mice. This generated neo-epitopes that were recognized by autoreactive IgG from the sera of patients with IgA nephropathy. Mice expressing human IgA1 and the human Fc α receptor I (α1KI-CD89tg) that underwent intestinal colonization by A. muciniphila developed an aggravated IgA nephropathy phenotype. After deglycosylation of IgA1 by A. muciniphila in the mouse gut lumen, IgA1 crossed the intestinal epithelium into the circulation by retrotranscytosis and became deposited in the glomeruli of mouse kidneys. Human α-defensins-a risk locus for IgA nephropathy-inhibited growth of A. muciniphila in vitro. A negative correlation observed between stool concentration of α-defensin 6 and quantity of A. muciniphila in the guts of control participants was lost in patients with IgA nephropathy. This study demonstrates that gut microbiota dysbiosis contributes to generation of auto-antigens in patients with IgA nephropathy and in a mouse model of this disease.

A survey study on antibiotic prescription practices for acute asthma exacerbations: An European academy of allergy and clinical immunology task force report

INTRODUCTION

Guidelines recommend treating asthma exacerbations (AAEs) with bronchodilators combined with inhaled and/or systemic corticosteroids. Indications for antibiotic prescriptions for AAEs are usually not incorporated although the literature shows antibiotics are frequently prescribed.

AIM

To investigate the antibiotic prescription rates in AAEs and explore the possible determining factors of those practices.

METHODS

A digital survey was created to determine the antibiotic prescription rates in AAEs and the influencing factors for the prescription practices. The survey was distributed among European academy of allergy and clinical immunology (EAACI) members by mass emailing and through regional/national societies in the Netherlands, Italy, Greece, and Poland. Furthermore, we retrieved local antibiotic prescription rates.

RESULTS

In total, 252 participants completed the survey. Respondents stated that there is a lack of guidelines to prescribe antibiotics in AAEs. The median antibiotic prescription rate in this study was 19% [IQR: 0%-40%] and was significantly different between 4 professions: paediatrics 0% [IQR: 0%-37%], pulmonologists 25% [IQR: 10%-50%], general practitioners 25% [IQR: 0%-50%], and allergologists 17% [IQR: 0%-33%]) (p = 0.046). Additional diagnostic tests were performed in 71.4% of patients before prescription and the most common antibiotic classes prescribed were macrolides (46.0%) and penicillin (42.9%). Important clinical factors for health care providers to prescribe antibiotics were colorised/purulent sputum, abnormal lung sounds during auscultation, fever, and presence of comorbidities.

CONCLUSION

In 19% of patients with AAEs, antibiotics were prescribed in various classes with a broad range among different subspecialities. This study stresses the urgency to compose evidence-based guidelines to aim for more rational antibiotic prescriptions for AAE.

Association between gut microbiota development and allergy in infants born during pandemic-related social distancing restrictions

BACKGROUND

Several hypotheses link reduced microbial exposure to increased prevalence of allergies. Here we capitalize on the opportunity to study a cohort of infants (CORAL), raised during COVID-19 associated social distancing measures, to identify the environmental exposures and dietary factors that contribute to early life microbiota development and to examine their associations with allergic outcomes.

METHODS

Fecal samples were sequenced from infants at 6 (n = 351) and repeated at 12 (n = 343) months, using 16S sequencing. Published 16S data from pre-pandemic cohorts were included for microbiota comparisons. Online questionnaires collected epidemiological information on home environment, healthcare utilization, infant health, allergic diseases, and diet. Skin prick testing (SPT) was performed at 12 (n = 343) and 24 (n = 320) months of age, accompanied by atopic dermatitis and food allergy assessments.

RESULTS

The relative abundance of bifidobacteria was higher, while environmentally transmitted bacteria such as Clostridia was lower in CORAL infants compared to previous cohorts. The abundance of multiple Clostridia taxa correlated with a microbial exposure index. Plant based foods during weaning positively impacted microbiota development. Bifidobacteria levels at 6 months of age, and relative abundance of butyrate producers at 12 months of age, were negatively associated with AD and SPT positivity. The prevalence of allergen sensitization, food allergy, and AD did not increase over pre-pandemic levels.

CONCLUSIONS

Environmental exposures and dietary components significantly impact microbiota community assembly. Our results also suggest that vertically transmitted bacteria and appropriate dietary supports may be more important than exposure to environmental microbes alone for protection against allergic diseases in infancy.

Systematic review of the association between short chain fatty acids and allergic diseases

We performed a systematic review to investigate the current evidence on the association between allergic diseases and short chain fatty acids (SCFAs), which are microbially produced and suggested as one mechanism on how gut microbiome affects the risk of allergic diseases. Medline, Embase and Web of Science were searched from data inception until September 2022. We identified 37 papers, of which 17 investigated prenatal or early childhood SCFAs and the development of allergic diseases in childhood, and 20 assessed SCFAs in patients with pre-existing allergic diseases. Study design, study populations, outcome definition, analysis method and reporting of the results varied between papers. Overall, there was some evidence showing that the three main SCFAs (acetate, propionate and butyrate) in the first few years of life had a protective effect against allergic diseases, especially for atopic dermatitis, wheeze or asthma and IgE-mediated food allergy in childhood. The association between each SCFA and allergic disease appeared to be different by disease and the age of assessment. Further research that can determine the potentially timing specific effect of each SCFA will be useful to investigate how SCFAs can be used in treatment or in prevention against allergic diseases.

Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.

A cross talk between microbial metabolites and host immunity: Its relevance for allergic diseases

BACKGROUND

Allergic diseases, including respiratory and food allergies, as well as allergic skin conditions have surged in prevalence in recent decades. In allergic diseases, the gut microbiome is dysbiotic, with reduced diversity of beneficial bacteria and increased abundance of potential pathogens. Research findings suggest that the microbiome, which is highly influenced by environmental and dietary factors, plays a central role in the development, progression, and severity of allergic diseases. The microbiome generates metabolites, which can regulate many of the host's cellular metabolic processes and host immune responses.

AIMS AND METHODS

Our goal is to provide a narrative and comprehensive literature review of the mechanisms through which microbial metabolites regulate host immune function and immune metabolism both in homeostasis and in the context of allergic diseases.

RESULTS AND DISCUSSION

We describe key microbial metabolites such as short-chain fatty acids, amino acids, bile acids and polyamines, elucidating their mechanisms of action, cellular targets and their roles in regulating metabolism within innate and adaptive immune cells. Furthermore, we characterize the role of bacterial metabolites in the pathogenesis of allergic diseases including allergic asthma, atopic dermatitis and food allergy.

CONCLUSION

Future research efforts should focus on investigating the physiological functions of microbiota-derived metabolites to help develop new diagnostic and therapeutic interventions for allergic diseases.

Immune Mechanisms Underpinning Long COVID: Collegium Internationale Allergologicum Update 2024

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can result in a prolonged multisystem disorder termed long COVID, which may affect up to 10% of people following coronavirus disease 2019 (COVID-19). It is currently unclear why certain individuals do not fully recover following SARS-CoV-2 infection.

SUMMARY

In this review, we examine immunological mechanisms that may underpin the pathophysiology of long COVID. These mechanisms include an inappropriate immune response to acute SARS-CoV-2 infection, immune cell exhaustion, immune cell metabolic reprogramming, a persistent SARS-CoV-2 reservoir, reactivation of other viruses, inflammatory responses impacting the central nervous system, autoimmunity, microbiome dysbiosis, and dietary factors.

KEY MESSAGES

Unfortunately, the currently available diagnostic and treatment options for long COVID are inadequate, and more clinical trials are needed that match experimental interventions to underlying immunological mechanisms.

A systematic review and meta-analysis on nutritional and dietary interventions for the treatment of acute respiratory infection in pediatric patients: An EAACI taskforce

Acute respiratory infections are a major cause of morbidity and mortality in children worldwide. Dietary and nutritional interventions, including minerals and vitamin supplementation, have been explored as potential treatments for these infections. However, the evidence on their efficacy is limited and inconclusive. This systematic review and meta-analysis aim to provide a comprehensive summary of the available evidence on the effectiveness of dietary and nutritional interventions for treating acute respiratory tract infections in children. A systematic review was conducted according to the PRISMA 2020 guidelines in April 2022 and updated in April 2023. Clinical trials focusing on dietary or nutritional interventions, including supplementations, in children with acute respiratory tract infections were included. The selection of interventions and outcomes was based on biological plausibility. Data were extracted using a standardized form, and the risk of bias was assessed using the Cochrane Risk of Bias Tool. Meta-analysis was performed using random-effect models. A total of 50 studies were included in the review. Four trials were conducted in low, 32 in lower-middle, 12 in upper-middle, and only two in high-income countries. The studies evaluated various dietary interventions, including zinc, vitamin A, vitamin E, vitamin D, and probiotics. The results of individual studies on the efficacy of these interventions were mixed, with some showing positive effects on clinical outcomes such as duration of symptoms, while others showed no significant impact. Meta-analysis was conducted for zinc supplementation in children with pneumonia, and the pooled results suggested a potential limited benefit in terms of reduced hospital length of stay but not time to recovery. Meta-analyses on vitamin D did not show any effect in children with pneumonia. This systematic review fills a critical gap in the literature by synthesizing the available evidence on the efficacy and safety of nutritional or dietary interventions for acute respiratory tract infections in children. The findings indicate no dietary or nutritional intervention can currently be recommended for the routine treatment of respiratory tract infections in children based on single supplement studies. The metanalysis suggests that zinc supplementation might have a beneficial effect on length of hospitalization in children with pneumonia. New studies are needed to establish more conclusive evidence for pediatric acute respiratory diseases especially for children living in a context of high-income countries.

Rural and urban exposures shape early life immune development in South African children with atopic dermatitis and nonallergic children

BACKGROUND

Immunological traits and functions have been consistently associated with environmental exposures and are thought to shape allergic disease susceptibility and protection. In particular, specific exposures in early life may have more significant effects on the developing immune system, with potentially long-term impacts.

METHODS

We performed RNA-Seq on peripheral blood mononuclear cells (PBMCs) from 150 children with atopic dermatitis and healthy nonallergic children in rural and urban settings from the same ethnolinguistic AmaXhosa background in South Africa. We measured environmental exposures using questionnaires.

RESULTS

A distinct PBMC gene expression pattern was observed in those children with atopic dermatitis (132 differentially expressed genes [DEGs]). However, the predominant influences on the immune cell transcriptome were related to early life exposures including animals, time outdoors, and types of cooking and heating fuels. Sample clustering revealed two rural groups (Rural_1 and Rural_2) that separated from the urban group (3413 and 2647 DEGs, respectively). The most significantly regulated pathways in Rural_1 children were related to innate activation of the immune system (e.g., TLR and cytokine signaling), changes in lymphocyte polarization (e.g., TH17 cells), and immune cell metabolism (i.e., oxidative phosphorylation). The Rural_2 group displayed evidence for ongoing lymphocyte activation (e.g., T cell receptor signaling), with changes in immune cell survival and proliferation (e.g., mTOR signaling, insulin signaling).

CONCLUSIONS

This study highlights the importance of the exposome on immune development in early life and identifies potentially protective (e.g., animal) exposures and potentially detrimental (e.g., pollutant) exposures that impact key immunological pathways.

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Physicochemical Characterization and Immunomodulatory Activity of Polyelectrolyte Multilayer Coatings Incorporating an Exopolysaccharide from Bifidobacterium longum

Immunoregulatory polysaccharides from probiotic bacteria have potential in biomedical engineering. Here, a negatively charged exopolysaccharide from Bifidobacterium longum with confirmed immunoregulatory activity (EPS624) was applied in multilayered polyelectrolyte coatings with positively charged chitosan. EPS624 and coatings (1, 5, and 10 layers and alginate-substituted) were characterized by the zeta potential, dynamic light scattering, size exclusion chromatography, scanning electron microscopy, and atomic force microscopy. Peripheral blood mononuclear cells (hPBMCs) and fibroblasts were exposed for 1, 3, 7, and 10 days with cytokine secretion, viability, and morphology as observations. The coatings showed an increased rugosity and exponential growth mode with an increasing number of layers. A dose/layer-dependent IL-10 response was observed in hPBMCs, which was greater than EPS624 in solution and was stable over 7 days. Fibroblast culture revealed no toxicity or metabolic change after exposure to EPS624. The EPS624 polyelectrolyte coatings are cytocompatible, have immunoregulatory properties, and may be suitable for applications in biomedical engineering.

EAACI guidelines on the diagnosis of IgE-mediated food allergy

This European Academy of Allergy and Clinical Immunology guideline provides recommendations for diagnosing IgE-mediated food allergy and was developed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. Food allergy diagnosis starts with an allergy-focused clinical history followed by tests to determine IgE sensitization, such as serum allergen-specific IgE (sIgE) and skin prick test (SPT), and the basophil activation test (BAT), if available. Evidence for IgE sensitization should be sought for any suspected foods. The diagnosis of allergy to some foods, such as peanut and cashew nut, is well supported by SPT and serum sIgE, whereas there are less data and the performance of these tests is poorer for other foods, such as wheat and soya. The measurement of sIgE to allergen components such as Ara h 2 from peanut, Cor a 14 from hazelnut and Ana o 3 from cashew can be useful to further support the diagnosis, especially in pollen-sensitized individuals. BAT to peanut and sesame can be used additionally. The reference standard for food allergy diagnosis is the oral food challenge (OFC). OFC should be performed in equivocal cases. For practical reasons, open challenges are suitable in most cases. Reassessment of food allergic children with allergy tests and/or OFCs periodically over time will enable reintroduction of food into the diet in the case of spontaneous acquisition of oral tolerance.

Nomenclature of allergic diseases and hypersensitivity reactions: Adapted to modern needs: An EAACI position paper

The exponential growth of precision diagnostic tools, including omic technologies, molecular diagnostics, sophisticated genetic and epigenetic editing, imaging and nano-technologies and patient access to extensive health care, has resulted in vast amounts of unbiased data enabling in-depth disease characterization. New disease endotypes have been identified for various allergic diseases and triggered the gradual transition from a disease description focused on symptoms to identifying biomarkers and intricate pathogenetic and metabolic pathways. Consequently, the current disease taxonomy has to be revised for better categorization. This European Academy of Allergy and Clinical Immunology Position Paper responds to this challenge and provides a modern nomenclature for allergic diseases, which respects the earlier classifications back to the early 20th century. Hypersensitivity reactions originally described by Gell and Coombs have been extended into nine different types comprising antibody- (I-III), cell-mediated (IVa-c), tissue-driven mechanisms (V-VI) and direct response to chemicals (VII). Types I-III are linked to classical and newly described clinical conditions. Type IVa-c are specified and detailed according to the current understanding of T1, T2 and T3 responses. Types V-VI involve epithelial barrier defects and metabolic-induced immune dysregulation, while direct cellular and inflammatory responses to chemicals are covered in type VII. It is notable that several combinations of mixed types may appear in the clinical setting. The clinical relevance of the current approach for allergy practice will be conferred in another article that will follow this year, aiming at showing the relevance in clinical practice where various endotypes can overlap and evolve over the lifetime.

Disrupted epithelial permeability as a predictor of severe COVID-19 development

BACKGROUND

An impaired epithelial barrier integrity in the gastrointestinal tract is important to the pathogenesis of many inflammatory diseases. Accordingly, we assessed the potential of biomarkers of epithelial barrier dysfunction as predictive of severe COVID-19.

METHODS

Levels of bacterial DNA and zonulin family peptides (ZFP) as markers of bacterial translocation and intestinal permeability and a total of 180 immune and inflammatory proteins were analyzed from the sera of 328 COVID-19 patients and 49 healthy controls.

RESULTS

Significantly high levels of circulating bacterial DNA were detected in severe COVID-19 cases. In mild COVID-19 cases, serum bacterial DNA levels were significantly lower than in healthy controls suggesting epithelial barrier tightness as a predictor of a mild disease course. COVID-19 patients were characterized by significantly elevated levels of circulating ZFP. We identified 36 proteins as potential early biomarkers of COVID-19, and six of them (AREG, AXIN1, CLEC4C, CXCL10, CXCL11, and TRANCE) correlated strongly with bacterial translocation and can be used to predict and discriminate severe cases from healthy controls and mild cases (area under the curve (AUC): 1 and 0.88, respectively). Proteomic analysis of the serum of 21 patients with moderate disease at admission which progressed to severe disease revealed 10 proteins associated with disease progression and mortality (AUC: 0.88), including CLEC7A, EIF4EBP1, TRANCE, CXCL10, HGF, KRT19, LAMP3, CKAP4, CXADR, and ITGB6.

CONCLUSION

Our results demonstrate that biomarkers of intact or defective epithelial barriers are associated with disease severity and can provide early information on the prediction at the time of hospital admission.

Atopic outcomes at 2 years in the CORAL cohort, born in COVID-19 lockdown

INTRODUCTION

The CORAL study is a cohort of infants born during the first weeks of the first SARS-CoV-2 (COVID-19) lockdown. This cohort has had lower antibiotic exposure, higher breastfeeding rates and lower infection rates, especially in the first year of life. We hypothesized that the altered early-life environment of infants born during lockdown would change the incidence of allergic conditions.

METHODS

This longitudinal, observational study followed 365 infants born between March and May 2020 from enrolment to the age of 2 years. Infants attended three research appointments at 6-, 12-, and 24-months and completed detailed questionnaires. At research appointments, children had skin prick testing, and atopic dermatitis (AD) assessment. Statistical analysis focused on changes within the group at different time points, the influence of specific environmental factors on allergic risk and compared the incidence of atopic conditions with a pre-pandemic Irish infant cohort, BASELINE.

RESULTS

AD was more common in CORAL group at both 12 (26.5% vs. 15.5%; p < .001) and 24 months (21.3% vs. 15.9%; p = .02) compared with pre-pandemic BASELINE cohort. Within the CORAL group, those with AD at both 12- and 24-month appointments had a more severe AD phenotype associated with a higher risk of allergic sensitization. There was less milk (0% vs. 1%; p = .09), peanut (0.6% vs. 1.8%; p = .3), and egg allergy (0% vs. 2.9%; p < .001) in the CORAL group at 24 months compared with the BASELINE cohort. Aeroallergen sensitization increased between 12 and 24 months in the CORAL cohort (1.5% vs. 8.9%; p < .001), as did parent-reported wheezing episodes (9% vs. 24%; p < .001).

CONCLUSIONS

Despite higher AD incidence in the CORAL cohort, the incidence of food sensitization and allergy are lower than expected pre-pandemic rates possibly reflecting the early introduction and maintenance of dietary allergens enhanced by changes in infant infections, antibiotic use, and breastfeeding in the first 2 years of life in the group. These beneficial effects of the lockdown could be outweighing the expected risk of less early-life microbial encounters outlined by the hygiene hypothesis.

An update on recent developments and highlights in food allergy

While both the incidence and general awareness of food allergies is increasing, the variety and clinical availability of therapeutics remain limited. Therefore, investigations into the potential factors contributing to the development of food allergy (FA) and the mechanisms of natural tolerance or induced desensitization are required. In addition, a detailed understanding of the pathophysiology of food allergies is needed to generate compelling, enduring, and safe treatment options. New findings regarding the contribution of barrier function, the effect of emollient interventions, mechanisms of allergen recognition, and the contributions of specific immune cell subsets through rodent models and human clinical studies provide novel insights. With the first approved treatment for peanut allergy, the clinical management of FA is evolving toward less intensive, alternative approaches involving fixed doses, lower maintenance dose targets, coadministration of biologicals, adjuvants, and tolerance-inducing formulations. The ultimate goal is to improve immunotherapy and develop precision-based medicine via risk phenotyping allowing optimal treatment for each food-allergic patient.

Rhinovirus-induced epithelial RIG-I inflammasome suppresses antiviral immunity and promotes inflammation in asthma and COVID-19

Rhinoviruses and allergens, such as house dust mite are major agents responsible for asthma exacerbations. The influence of pre-existing airway inflammation on the infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is largely unknown. We analyse mechanisms of response to viral infection in experimental in vivo rhinovirus infection in healthy controls and patients with asthma, and in in vitro experiments with house dust mite, rhinovirus and SARS-CoV-2 in human primary airway epithelium. Here, we show that rhinovirus infection in patients with asthma leads to an excessive RIG-I inflammasome activation, which diminishes its accessibility for type I/III interferon responses, leading to their early functional impairment, delayed resolution, prolonged viral clearance and unresolved inflammation in vitro and in vivo. Pre-exposure to house dust mite augments this phenomenon by inflammasome priming and auxiliary inhibition of early type I/III interferon responses. Prior infection with rhinovirus followed by SARS-CoV-2 infection augments RIG-I inflammasome activation and epithelial inflammation. Timely inhibition of the epithelial RIG-I inflammasome may lead to more efficient viral clearance and lower the burden of rhinovirus and SARS-CoV-2 infections.

Akkermansia muciniphila reduces susceptibility to Listeria monocytogenes infection in mice fed a high-fat diet

A high-fat (HF) diet reduces resistance to the foodborne pathogen Listeria monocytogenes. We demonstrate that short-term gavage with A. muciniphila increases resistance to oral and systemic L. monocytogenes infection in mice fed a HF diet. A. muciniphila reduced inflammation in the gut and liver of mice fed a high-fat diet prior to infection and reduced inflammatory cell infiltration in the ileum to levels similar to mice fed a low-fat (LF) diet. Akkermansia administration had minimal impacts upon the microbiota and microbial metabolites and did not affect individual taxa or impact the Bacteroidetes to Firmicutes ratio. In summary, A. muciniphila increased resistance to L. monocytogenes infection in mice fed a HF diet by moderating immune/physiological effects through specific interaction between A. muciniphila and the host gut.

Comparing the Diagnostic Accuracy of Measures of Maternal Diet During Pregnancy for Offspring Allergy Outcomes: The Healthy Start Study

BACKGROUND

Allergic diseases in children are increasing. Although maternal diet quality in pregnancy may be protective, it is unclear which measure of maternal diet best predicts offspring diseases.

OBJECTIVE

To examine the associations between multiple diet measures and allergy outcomes, and to compare the diagnostic accuracy of the measures for the prediction of allergy outcomes.

METHODS

Maternal diet during pregnancy was measured using a validated instrument, and scored using 5 measures: the maternal diet index (MDI), Healthy Eating Index, total diet diversity, healthy diet diversity, and unhealthy diet diversity. Unadjusted and adjusted logistic regression models assessed associations between maternal diet measures and offspring allergy outcomes up to age 4 years. The diagnostic accuracy of the diet measures was compared.

RESULTS

There were significant associations between MDI (odds ratio [OR], 0.78; 95% CI, 0.70-0.87), Healthy Eating Index (OR, 0.98; 95% CI, 0.97-0.99), and healthy diet diversity scores (OR, 0.91; 95% CI, 0.85-0.98) during pregnancy and the primary combined outcome "any allergy excluding wheeze" in children up to age 4 years. Neither maternal total diet diversity (OR, 0.99; 95% CI, 0.95-1.03) nor unhealthy diet diversity scores (OR, 1.05; 95% CI, 0.98-1.13) were associated with the "any allergy excluding wheeze" outcome. For all outcomes studied, except for food allergy, there was a significant difference in the diagnostic accuracy between the 5 measures of maternal diet. The area under the curve for MDI was highest for every disease outcome, although not always significantly higher.

CONCLUSIONS

Better quality and higher diversity of a woman's diet during pregnancy, measured in various ways, is associated with offspring allergy outcomes, with healthy foods associated with decreased risk, and unhealthy foods associated with a higher risk. The MDI, which appropriately weighted both healthy and unhealthy foods, best predicted childhood allergic disease.

Questioning the fetal microbiome illustrates pitfalls of low-biomass microbial studies

Whether the human fetus and the prenatal intrauterine environment (amniotic fluid and placenta) are stably colonized by microbial communities in a healthy pregnancy remains a subject of debate. Here we evaluate recent studies that characterized microbial populations in human fetuses from the perspectives of reproductive biology, microbial ecology, bioinformatics, immunology, clinical microbiology and gnotobiology, and assess possible mechanisms by which the fetus might interact with microorganisms. Our analysis indicates that the detected microbial signals are likely the result of contamination during the clinical procedures to obtain fetal samples or during DNA extraction and DNA sequencing. Furthermore, the existence of live and replicating microbial populations in healthy fetal tissues is not compatible with fundamental concepts of immunology, clinical microbiology and the derivation of germ-free mammals. These conclusions are important to our understanding of human immune development and illustrate common pitfalls in the microbial analyses of many other low-biomass environments. The pursuit of a fetal microbiome serves as a cautionary example of the challenges of sequence-based microbiome studies when biomass is low or absent, and emphasizes the need for a trans-disciplinary approach that goes beyond contamination controls by also incorporating biological, ecological and mechanistic concepts.

Environmental influences on childhood asthma-The effect of diet and microbiome on asthma

Early life dietary patterns and timely maturation of mucosa-associated microbial communities are important factors influencing immune development and for establishing robust immune tolerance networks. Microbial fermentation of dietary components in vivo generates a vast array of molecules, some of which are integral components of the molecular circuitry that regulates immune and metabolic functions. These in turn protect against aberrant inflammatory processes and promote effector immune responses that quickly eliminate pathogens. Multiple studies suggest that changes in dietary habits, altered microbiome composition, and microbial metabolism are associated with asthma risk and disease severity. While it remains unclear whether these microbiome alterations are a cause or consequence of dysregulated immune responses, there is significant potential for using diet in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health. In this article, we will summarize our knowledge to date on the role of dietary patterns and microbiome activities on immune responses within the airways. Given the malleability of the human microbiome, its integration into the immune system, and its responsiveness to diet, this makes it a highly attractive target for therapeutic and nutritional intervention in children with asthma.

Immunomodulation by foods and microbes: Unravelling the molecular tango

Metabolic health and immune function are intimately connected via diet and the microbiota. Nearly 90% of all immune cells in the body are associated with the gastrointestinal tract and these immune cells are continuously exposed to a wide range of microbes and microbial-derived compounds, with important systemic ramifications. Microbial dysbiosis has consistently been observed in patients with atopic dermatitis, food allergy and asthma and the molecular mechanisms linking changes in microbial populations with disease risk and disease endotypes are being intensively investigated. The discovery of novel bacterial metabolites that impact immune function is at the forefront of host-microbe research. Co-evolution of microbial communities within their hosts has resulted in intertwined metabolic pathways that affect physiological and pathological processes. However, recent dietary and lifestyle changes are thought to negatively influence interactions between microbes and their host. This review provides an overview of some of the critical metabolite-receptor interactions that have been recently described, which may underpin the immunomodulatory effects of the microbiota, and are of relevance for allergy, asthma and infectious diseases.

Role of dietary fiber in promoting immune health-An EAACI position paper

Microbial metabolism of specific dietary components, such as fiber, contributes to the sophisticated inter-kingdom dialogue in the gut that maintains a stable environment with important beneficial physiological, metabolic, and immunological effects on the host. Historical changes in fiber intake may be contributing to the increase of allergic and hypersensitivity disorders as fiber-derived metabolites are evolutionarily hardwired into the molecular circuitry governing immune cell decision-making processes. In this review, we highlight the importance of fiber as a dietary ingredient, its effects on the microbiome, its effects on immune regulation, the importance of appropriate timing of intervention to target any potential window of opportunity, and potential mechanisms for dietary fibers in the prevention and management of allergic diseases. In addition, we review the human studies examining fiber or prebiotic interventions on asthma and respiratory outcomes, allergic rhinitis, atopic dermatitis, and overall risk of atopic disorders. While exposures, interventions, and outcomes were too heterogeneous for meta-analysis, there is significant potential for using fiber in targeted manipulations of the gut microbiome and its metabolic functions in promoting immune health.

36 WHAT DO OLDER ADULTS AND HEALTH CARE PROFESSIONALS LOOK FOR IN A FOOD PRODUCT?

Background

The Mediterranean diet (Medi-diet) has proven benefits for healthy ageing but isn’t the habitual diet of most middle-aged or older adults in Ireland; there can be accessibility and tolerability issues with high amounts of fresh fruit and vegetables. Providing key Medi-diet nutrients in a food product is a novel approach to this challenge. This research aims to explore what ‘younger-old’ adults and healthcare professionals (HCPs) would value in such a novel food product.

Methods

Semi-structured 1:1 interviews and Focus Groups (FGs) were conducted remotely from July 2021 to January 2022. Older adults, defined as over 55’s, were recruited through relevant social, retirement and disease-support groups. Purposive sampling recruited a gender balance and a range of ages and disease profiles. HCPs were recruited through researcher networks and professional associations. Interviews/FGs were recorded, transcribed, and subsequently examined using inductive thematic analysis.

Results

Older adults (n=47; 50% male) were mostly aged 60-69 years (48.9%). Recruited HCPs (n=26) included dieticians (n=8); geriatricians (n=5); therapists (n=4); and nurses, pharmacists, catering managers (community; residential), and meal delivery service coordinators (n=2 each). Participants supported a food product for older adults requiring a nutrient-dense “boost”, or supplementary fibre or protein, but generally preferred a “food-first” approach, as opposed to a “silver bullet” product. Older adults largely associated functional foods with probiotic products “to repair the gut”, something to have “every now and then”. Product texture and portion size should consider changing dentition and appetite, and consider packaging (dexterity) and preparation ease, but should not stigmatize older adults through targeted branding. Participants felt pre-made soups or cake-type bars would be appealing, but not drinks.

Conclusion

A novel food product could supplement a balanced diet for older adults, providing high-protein content, and high-fibre for gut health, complimenting an overall lifestyle approach to health improvement and disease prevention.

Associations between child filaggrin mutations and maternal diet with the development of allergic diseases in children

BACKGROUND

Filaggrin (FLG) loss-of-function mutations in children and maternal diet in pregnancy have been implicated in child allergy outcomes. This paper studies the questions: "do FLG mutations modify the effect of maternal diet on the odds of development of allergic diseases?" and "which factor leads to the highest rate of diagnosis allergic diseases over time, maternal diet, or FLG mutations?".

METHODS

Exact logistic regressions studied effect modification. Cox proportional hazard models compared the rate of allergic disease development in three groups (N = 624): (1) children with FLG mutation, (2) children without FLG mutation whose mothers did not eat an allergy preventive diet, and (3) children without FLG mutation whose mothers ate an allergy preventive diet. Maternal diet was classified using a validated index.

RESULTS

Cox models showed the development of atopic dermatitis, asthma, and wheeze was significantly higher for children in group 1 versus 3 (HR = 2.40 [1.32, 4.37], HR = 2.29 [1.05, 4.97], and HR 2.10 [1.004, 4.38], respectively), but not significantly higher for children in group 1 versus 2 (HR = 1.30 [0.74, 2.29], HR = 1.27 [0.61, 2.63], and HR = 1.29 [0.65, 2.58], respectively). Development of allergic rhinitis was significantly higher for group 1 versus 2 and 3 (1 vs. 2: HR = 2.29 [1.10, 4.76]; 1 vs. 3: HR = 3.21 [1.46, 7.08]). There was no significant effect modification for any outcome.

CONCLUSION

Children with FLG mutation had similar risk of atopic dermatitis, asthma, and wheeze as children without an FLG mutation whose mothers did not eat an allergy preventive diet during pregnancy. Child FLG mutation did not modify the effect of maternal diet. The results suggest that maternal diet in pregnancy, a modifiable risk factor, could be a target for preventive interventions.

Parenting a newborn baby during the COVID-19 pandemic: a qualitative survey

OBJECTIVE

The COVID-19 pandemic caused long periods of lockdown, social isolation and intense challenges for parents. This study examines parenting in an infant cohort born at the pandemic onset.

METHODS

The CORAL study is a prospective longitudinal observational study looking at allergy, immune function and neurodevelopmental outcome in babies born between March and May 2020. Demographic information was collected, babies were reviewed at 6-monthly intervals, and serology for COVID-19 infection was recorded. When babies were 12 months old, parents were asked for 3-5 words to describe raising a baby during the pandemic. Frequency of word usage was compared between first time parents and parents with other children, and parents of babies with and without a diagnosis of COVID-19 infection.

RESULTS

354 babies were recruited to CORAL study. Social circles were small. At 6 months the median number of people (including parents) who had kissed the baby was 3, and by 12 months one-quarter of babies had never met another child of similar age. 304 parents completed the word choice. Commonly reported words were lonely (44.4%), isolating (31.9%) and strong bond (15.8%). 12 of those 304 babies had COVID-19 in their first year of life and there was no significant difference in reported negative or positive word number compared with parents of babies without a COVID-19 infection, or by first time parents or those who already had children.

CONCLUSION

The lockdowns and social restrictions made raising an infant challenging for all parents in Ireland. It is important parents know this was a shared experience.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti‐inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS‐CoV‐2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID‐19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs‐exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID‐19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID‐19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

Environment-dependent alterations of immune mediators in urban and rural South African children with atopic dermatitis

BACKGROUND

In order to improve targeted therapeutic approaches for children with atopic dermatitis (AD), novel insights into the molecular mechanisms and environmental exposures that differentially contribute to disease phenotypes are required. We wished to identify AD immunological endotypes in South African children from rural and urban environments.

METHODS

We measured immunological, socio-economic and environmental factors in healthy children (n = 74) and children with AD (n = 78), in rural and urban settings from the same ethno-linguistic AmaXhosa background in South Africa.

RESULTS

Circulating eosinophils, monocytes, TARC, MCP-4, IL-16 and allergen-specific IgE levels were elevated, while IL-17A and IL-23 levels were reduced, in children with AD regardless of their location. Independent of AD, children living in a rural environment had the highest levels of TNFα, TNFβ, IL-1α, IL-6, IL-8, IL-21, MCP-1, MIP-1α, MIP-1β, MDC, sICAM1, sVCAM1, VEGFA, VEGFD and Tie2, suggesting a generalized microinflammation or a pattern of trained immunity without any specific T_H polarization. In contrast, IL-15, IL-22, Flt1, PIGF and βFGF were highest in urban children. Rural healthy children had the lowest levels of food allergen-specific IgG4. Early life nutritional factors, medications, animal exposures, indoor environment, sunlight exposure, household size, household income and parental education levels were associated with differences in circulating cytokine levels.

CONCLUSIONS

This study highlights the immunological impact of environmental exposures and socio-economic status in the manifestation of immune endotypes in children with AD living in urban and rural areas, which are important in selecting appropriately matched immunological therapies for treatment of AD.

The maternal diet index in pregnancy is associated with offspring allergic diseases: the Healthy Start study

BACKGROUND

A systematic review showed limited associations between pregnancy diet and offspring allergy. We developed a maternal diet index during pregnancy that was associated with offspring allergy outcomes.

METHODS

Data came from Healthy Start, a Colorado pre-birth cohort of mother/offspring dyads. Food propensity questionnaires were completed during pregnancy. Offspring allergic rhinitis, atopic dermatitis, asthma, wheeze, and food allergy diagnosis up to age four were verified from electronic medical records. Data were randomized into test and replication sets. The index included the weighted combination of variables that best predicted a combined outcome of any allergy in the test set. Index utility was verified in the replication set. Separate adjusted and unadjusted logistic models estimated associations between the index and each offspring allergy diagnosis in the full sample.

RESULTS

The index included weighted measures of intake of vegetables, yogurt, fried potatoes, rice/grains, red meats, pure fruit juice, and cold cereals. Vegetables and yogurt were associated with the prevention of any allergy, while other components were associated with increased disease. In adjusted models, a one-unit increase in the index was significantly associated with reduced odds of offspring allergic rhinitis (odds ratio (CI) 0.82 [0.72-0.94]), atopic dermatitis (0.77 [0.69-0.86]), asthma (0.84 [0.74-0.96]), and wheeze (0.80 [0.71-0.90]), but not food allergy (0.84 [0.66-1.08]).

CONCLUSIONS

This is the first study that has shown associations between an index of maternal dietary intake during pregnancy and multiple offspring allergic diseases. The results give hope for prevention of allergic diseases in utero.

Advanced glycation end product intake during pregnancy and offspring allergy outcomes: A Prospective cohort study

BACKGROUND

Associations have been shown between concurrent assessment of dietary intake of advanced glycation end products (AGEs) and childhood allergic outcomes. We examined the association between maternal AGEs intake and development of offspring asthma, wheeze, atopic dermatitis, allergic rhinitis and food allergies, and sought to determine whether the intake of AGEs was associated with cord sera cytokines/chemokines.

METHODS

Pregnant women ≥16 years were recruited in the Healthy Start study, a prospective pre-birth cohort from Colorado (N = 1410). The analysis included 962 dyads with adequate diet (≥2 recalls) and allergy outcome details. AGEs intake was estimated for each mother by matching intakes reported using 24-h dietary recalls during pregnancy to a reference database of commonly consumed foods' AGEs values. Child diagnoses of asthma and allergies up to 8 years were obtained from electronic medical records. Cord sera cytokines and chemokines were analysed in a subset (N = 462) of children.

RESULTS

The median [IQR] AGEs intake for the overall sample was 11,919 kU/day [8293, 16,573]. Unadjusted analysis showed a positive association between maternal AGEs intake in pregnancy and rhinitis up to 8 years of age (HR = 1.03; 95% CI: 1.01, 1.06), but the association was attenuated and no longer significant in adjusted models (HR = 1.01; 95% CI: 0.98, 1.04). Both adjusted and unadjusted models showed no associations between AGEs intake in pregnancy and any of the other outcomes (p > .05). There were no significant associations between any cytokine or chemokine measured and AGEs intake or any of the outcomes studied (p > .05).

CONCLUSION

The study showed that maternal AGEs intake was not associated with offspring asthma and allergy outcomes. AGEs exposure during pregnancy may not have the same impact on child development as postnatal exposure.

Mechanisms of microbe-immune system dialogue within the skin

The prevalence and severity of dermatological conditions such as atopic dermatitis have increased dramatically during recent decades. Many of the factors associated with an altered risk of developing inflammatory skin disorders have also been shown to alter the composition and diversity of non-pathogenic microbial communities that inhabit the human host. While the most densely microbial populated organ is the gut, culture and non-culture-based technologies have revealed a dynamic community of bacteria, fungi, viruses and mites that exist on healthy human skin, which change during disease. In this review, we highlight some of the recent findings on the mechanisms through which microbes interact with each other on the skin and the signalling systems that mediate communication between the immune system and skin-associated microbes. In addition, we summarize the ongoing clinical studies that are targeting the microbiome in patients with skin disorders. While significant efforts are still required to decipher the mechanisms underpinning host-microbe communication relevant to skin health, it is likely that disease-related microbial communities, or Dermatypes, will help identify personalized treatments and appropriate microbial reconstitution strategies.

NSAIDs and Renal Impairment: Deprescribing Chronic NSAID use in General Practice

Aim NSAIDs are high-risk medicines that can commonly cause adverse renal effects. Recent evidence suggests a rise in the number of patients with acute and chronic renal disease. The aim of this audit is to determine our de-prescribing rate of chronic NSAID use in an Irish general practice. Methods We reviewed NSAID-containing drug prescriptions that were issued over a three month period in 2018. A description analysis was performed to ascertain for the frequency and type of NSAIDs prescribed. An educational session was delivered to clinicians to encourage de-prescribing of NSAIDs if deemed clinically appropriate. Results Fifty-one NSAID-containing prescriptions were identified. Thirty-six (71%) patients, who were prescribed a regular NSAID, were aged between 71-85 years. Meloxicam was used the most (31%), whilst the preferred NSAIDs (naproxen and ibuprofen) were used least (18%). A 37% improvement in de-prescribing of chronic NSAIDs was achieved upon re-auditing. Conclusion NSAIDs are commonly implicated in inappropriate prescribing. Clinicians are encouraged to practice de-prescribing at every opportunity. Recent evidence suggests that pharmacy-led educational interventions can further assist de-prescribing of inappropriate medicines. Thus, a close collaboration between physicians and pharmacists is encouraged to further maximise quality of prescribing and patient care.

Mouse Models of Asthma: Characteristics, Limitations and Future Perspectives on Clinical Translation

Asthma is a complex and heterogeneous inflammatory airway disease primarily characterized by airway obstruction, which affects up to 15% of the population in Westernized countries with an increasing prevalence. Descriptive laboratory and clinical studies reveal that allergic asthma is due to an immunological inflammatory response and is significantly influenced by an individual's genetic background and environmental factors. Due to the limitations associated with human experiments and tissue isolation, direct mouse models of asthma provide important insights into the disease pathogenesis and in the discovery of novel therapeutics. A wide range of asthma models are currently available, and the correct model system for a given experimental question needs to be carefully chosen. Despite recent advances in the complexity of murine asthma models, for example humanized murine models and the use of clinically relevant allergens, the limitations of the murine system should always be acknowledged, and it remains to be seen if any single murine model can accurately replicate all the clinical features associated with human asthmatic disease.

Cellular and molecular mechanisms of allergic asthma

Asthma is a chronic disease of the airways, which affects more than 350 million people worldwide. It is the most common chronic disease in children, affecting at least 30 million children and young adults in Europe. Asthma is a complex, partially heritable disease with a marked heterogeneity. Its development is influenced both by genetic and environmental factors. The most common, as well as the most well characterized subtype of asthma is allergic eosinophilic asthma, which is characterized by a type 2 airway inflammation. The prevalence of asthma has substantially increased in industrialized countries during the last 60 years. The mechanisms underpinning this phenomenon are incompletely understood, however increased exposure to various environmental pollutants probably plays a role. Disease inception is thought to be enabled by a disadvantageous shift in the balance between protective and harmful lifestyle and environmental factors, including exposure to protective commensal microbes versus infection with pathogens, collectively leading to airway epithelial cell damage and disrupted barrier integrity. Epithelial cell-derived cytokines are one of the main drivers of the type 2 immune response against innocuous allergens, ultimately leading to infiltration of lung tissue with type 2 T helper (T_H2) cells, type 2 innate lymphoid cells (ILC2s), M2 macrophages and eosinophils. This review outlines the mechanisms responsible for the orchestration of type 2 inflammation and summarizes the novel findings, including but not limited to dysregulated epithelial barrier integrity, alarmin release and innate lymphoid cell stimulation.

Efficacy and safety of treatment with biologicals for severe chronic rhinosinusitis with nasal polyps: A systematic review for the EAACI guidelines

This systematic review evaluates the efficacy and safety of biologicals for chronic rhinosinusitis with nasal polyps (CRSwNP) compared with the standard of care. PubMed, Embase, and Cochrane Library were searched for RCTs. Critical and important CRSwNP-related outcomes were considered. The risk of bias and the certainty of the evidence were assessed using GRADE. RCTs evaluated (dupilumab-2, omalizumab-4, mepolizumab-2, and reslizumab-1) included 1236 adults, with follow-up of 20-64 weeks. Dupilumab reduces the need for surgery (NFS) or oral corticosteroid (OCS) use (RR 0.28; 95% CI 0.20-0.39, moderate certainty) and improves with high certainty smell evaluated with UPSIT score (mean difference (MD) +10.54; 95% CI +9.24 to +11.84) and quality of life (QoL) evaluated with SNOT-22 (MD -19.14; 95% CI -22.80 to -15.47), with fewer treatment-related adverse events (TAEs) (RR 0.95; 95% CI 0.89-1.02, moderate certainty). Omalizumab reduces NFS (RR 0.85; 95% CI 0.78-0.92, high certainty), decreases OCS use (RR 0.38; 95% CI 0.10-1.38, moderate certainty), and improves high certainty smell (MD +3.84; 95% CI +3.64 to +4.04) and QoL (MD -15.65; 95% CI -16.16 to -15.13), with increased TAE (RR 1.73; 95% CI 0.60-5.03, moderate certainty). There is low certainty for mepolizumab reducing NFS (RR 0.78; 95% CI 0.64-0.94) and improving QoL (MD -13.3; 95% CI -23.93 to -2.67) and smell (MD +0.7; 95% CI -0.48 to +1.88), with increased TAEs (RR 1.64; 95% CI 0.41-6.50). The evidence for reslizumab is very uncertain.

Fracture biomechanics influence local and systemic immune responses in a murine fracture-related infection model

Biomechanical stability plays an important role in fracture healing, with unstable fixation being associated with healing disturbances. A lack of stability is also considered a risk factor for fracture-related infection (FRI), although confirmatory studies and an understanding of the underlying mechanisms are lacking. In the present study, we investigate whether biomechanical (in)stability can lead to altered immune responses in mice under sterile or experimentally inoculated conditions. In non-inoculated C57BL/6 mice, instability resulted in an early increase of inflammatory markers such as granulocyte-colony stimulating factor (G-CSF), keratinocyte chemoattractant (KC) and interleukin (IL)-6 within the bone. When inoculated with Staphylococcus epidermidis, instability resulted in a further significant increase in G-CSF, IL-6 and KC in bone tissue. Staphylococcus aureus infection led to rapid osteolysis and instability in all animals and was not further studied. Gene expression measurements also showed significant upregulation in CCL2 and G-CSF in these mice. IL-17A was found to be upregulated in all S. epidermidis infected mice, with higher systemic IL-17A cell responses in mice that cleared the infection, which was found to be produced by CD4+ and γδ+ T cells in the bone marrow. IL-17A knock-out (KO) mice displayed a trend of delayed clearance of infection (P=0.22, Fisher’s exact test) and an increase in interferon (IFN)-γ production. Biomechanical instability leads to a more pronounced local inflammatory response, which is exaggerated by bacterial infection. This study provides insights into long-held beliefs that biomechanics are crucial not only for fracture healing, but also for control of infection.

Summary: Physical movement between bone fragments after a fracture influence healing, and are shown here, for the first time, to influence immune responses and infection.

EAACI guideline: Preventing the development of food allergy in infants and young children (2020 update)

BACKGROUND

This guideline from the European Academy of Allergy and Clinical Immunology (EAACI) recommends approaches to prevent the development of immediate-onset / IgE-mediated food allergy in infants and young children. It is an update of a 2014 EAACI guideline.

METHODS

The guideline was developed using the AGREE II framework and the GRADE approach. An international Task Force with representatives from 11 countries and different disciplinary and clinical backgrounds systematically reviewed research and considered expert opinion. Recommendations were created by weighing up benefits and harms, considering the certainty of evidence and examining values, preferences and resource implications. The guideline was peer-reviewed by external experts, and feedback was incorporated from public consultation.

RESULTS

All of the recommendations about preventing food allergy relate to infants (up to 1 year) and young children (up to 5 years), regardless of risk of allergy. There was insufficient evidence about preventing food allergy in other age groups. The EAACI Task Force suggests avoiding the use of regular cow's milk formula as supplementary feed for breastfed infants in the first week of life. The EAACI Task Force suggests introducing well-cooked, but not raw egg or uncooked pasteurized, egg into the infant diet as part of complementary feeding. In populations where there is a high prevalence of peanut allergy, the EAACI Task Force suggests introducing peanuts in an age-appropriate form as part of complementary feeding. According to the studies, it appears that the most effective age to introduce egg and peanut is from four to 6 months of life. The EAACI Task Force suggests against the following for preventing food allergy: (i) avoiding dietary food allergens during pregnancy or breastfeeding; and (ii) using soy protein formula in the first 6 months of life as a means of preventing food allergy. There is no recommendation for or against the following: use of vitamin supplements, fish oil, prebiotics, probiotics or synbiotics in pregnancy, when breastfeeding or in infancy; altering the duration of exclusive breastfeeding; and hydrolysed infant formulas, regular cow's milk-based infant formula after a week of age or use of emollients.

CONCLUSIONS

Key changes from the 2014 guideline include suggesting (i) the introduction of peanut and well-cooked egg as part of complementary feeding (moderate certainty of evidence) and (ii) avoiding supplementation with regular cow's milk formula in the first week of life (low certainty of evidence). There remains uncertainty in how to prevent food allergy, and further well-powered, multinational research using robust diagnostic criteria is needed.

Vaccines and allergic reactions: The past, the current COVID-19 pandemic, and future perspectives

Vaccines are essential public health tools with a favorable safety profile and prophylactic effectiveness that have historically played significant roles in reducing infectious disease burden in populations, when the majority of individuals are vaccinated. The COVID-19 vaccines are expected to have similar positive impacts on health across the globe. While serious allergic reactions to vaccines are rare, their underlying mechanisms and implications for clinical management should be considered to provide individuals with the safest care possible. In this review, we provide an overview of different types of allergic adverse reactions that can potentially occur after vaccination and individual vaccine components capable of causing the allergic adverse reactions. We present the incidence of allergic adverse reactions during clinical studies and through post-authorization and post-marketing surveillance and provide plausible causes of these reactions based on potential allergenic components present in several common vaccines. Additionally, we review implications for individual diagnosis and management and vaccine manufacturing overall. Finally, we suggest areas for future research.

ARIA-EAACI statement on severe allergic reactions to COVID-19 vaccines - An EAACI-ARIA Position Paper

Further to the approval of the Coronavirus disease 2019 (COVID-19) vaccine BNT162b2, several severe anaphylaxis cases occured within the first few days of public vaccination. An investigation is taking place to understand the cases and their triggers. The vaccine will be administered to a large number of individuals worldwide and there are raising concerns that severe adverse events might occur. With the current information, the European Academy of Allergy and Clinical Immunology (EAACI) states its position for the following preliminary recommendations that are to be revised as soon as more data emerge. To minimize the risk of severe allergic reactions in vaccinated individuals, it is urgently required to understand the specific nature of the reported severe allergic reactions, including the background medical history of the individuals affected and the mechanisms involved. To achieve this goal, all clinical and laboratory information should be collected and reported. Mild and moderate allergic patients should not be excluded from the vaccine as this could have a significant impact on reaching the goal of population immunity. Healthcare practitioners vaccinating against COVID-19 are required to be sufficiently prepared to recognize and treat anaphylaxis properly with the ability to administer adrenaline. Further to vaccine administration, a mandatory observation period of at least 15 minutes should be followed for all individuals. The current data have not shown any higher risk for patients suffering from allergic rhinitis or asthma, and this message should be clearly stated by physicians to enable our patients to trust the vaccine. More than 30% of the population suffers from allergic diseases and the benefit of the vaccination clearly outweighs the risk of severe COVID-19 development.

An Exopolysaccharide Produced by Bifidobacterium longum 35624® Inhibits Osteoclast Formation via a TLR2-Dependent Mechanism

The probiotic Bifidobacterium longum subsp. longum 35624® (B. longum 35624®), with its surface exopolysaccharide (EPS624), has previously been demonstrated to induce immunoregulatory responses in the host and may, therefore, be a novel approach to prevent bone loss in inflammatory conditions such as post-menopausal osteoporosis (PMO). The aim of this study was to investigate the effect of EPS624 on osteoclast and osteoblast differentiation and to assess the potential of B. longum 35624® to prevent bone loss in vivo. In vitro cell assays were used to assess the impact of EPS624 on osteoclast and osteoblast differentiation. The potential of two probiotic B. longum 35624® strains, including an EPS-deficient strain, for preventing ovariectomy (Ovx)-induced bone loss was assessed in a murine model. EPS624 prevented osteoclast formation from murine bone marrow precursors under both normal and TNFα-induced inflammatory conditions and modestly increased mineralized matrix deposition in osteogenic cell cultures. However, in the presence of an anti-TLR2 blocking antibody, or in MyD88^-/- osteoclast precursors, the inhibitory effect of EPS624 on osteoclast formation was diminished or completely prevented, respectively. Moreover, EPS624 induced IL-10 production in osteoclast precursors in a TLR2-dependent manner, although IL-10 was dispensable in the EPS624-mediated inhibition of osteoclast formation. In addition, EPS624-producing B. longum 35624® partially prevented bone loss in Ovx mice when administered by oral gavage. This study introduced EPS624 as a potential anti-resorptive therapy, although optimal in vivo delivery of the probiotic strain for treating low-grade inflammatory diseases such as PMO remains to be determined.

Examining Associations Between Dietary Inflammatory Index in Pregnancy, Pro-inflammatory Cytokine and Chemokine Levels at Birth, and Offspring Asthma and/or Wheeze by Age 4 Years

BACKGROUND

Few studies have demonstrated associations between maternal dietary inflammatory index (DII) during pregnancy and offspring asthma and/or wheeze.

OBJECTIVE

The study aimed to assess associations between maternal DII during pregnancy and 1) offspring cord sera pro-inflammatory cytokines (interleukin [IL]-1β, IL-4, IL-6, IL-10, tumor necrosis factor-α) and chemokines (IL-8, monocyte chemoattractant protein-1) at birth and 2) offspring asthma and/or wheeze at age 4 years.

DESIGN

The Healthy Start study is a prospective prebirth longitudinal study that recruited pregnant women in Denver, Colorado and tracked their offspring.

PARTICIPANTS AND SETTING

This study used data from 1228 mother-child dyads enrolled in the Healthy Start study. Pregnant women were recruited in Denver, Colorado, between 2009 and 2014, and offspring tracked until age 4 years.

MAIN OUTCOME MEASURES

Cord sera cytokines and chemokines were analyzed with multiplex panel immunoassays. Offspring diagnosis of asthma and/or wheeze by age 4 years was extracted from electronic medical records.

STATISTICAL ANALYSES PERFORMED

Unadjusted and adjusted linear and logistic regression models were used to assess associations. Covariates included factors such as nulliparity, race/ethnicity, gestational smoking, and maternal history of asthma.

RESULTS

Unadjusted analysis showed that increasing maternal DII scores were associated with increased odds of child asthma and/or wheeze by 4 years (odds ratio = 1.17; 95% CI: 1.07-1.27), but the association was attenuated and no longer statistically significant in the adjusted model (odds ratio = 1.15; 95% CI: 0.99-1.33). There were no significant associations between DII scores and cord sera cytokine or chemokine levels.

CONCLUSIONS

The study showed that the inflammatory profile of the maternal diet was not associated with cytokines and chemokine levels at birth. The results suggested that a more inflammatory maternal diet was associated with increased odds of offspring asthma and/or wheeze by age 4 years, which could be considered of clinical relevance but the finding was not statistically significant at the .05 level.