The Prevalence of IgE-Mediated Food Allergy and Other Allergic Diseases in the First 10 Years: The Population-Based, Longitudinal HealthNuts Study

BACKGROUND

There are limited longitudinal data on the population prevalence of allergic conditions during childhood, and few studies have incorporated the reference standard oral food challenge to confirm food allergy.

OBJECTIVE

To describe the population prevalence of IgE-mediated food allergy, eczema, asthma, and rhinitis at ages 6 and 10 years in Melbourne, Australia.

METHODS

The HealthNuts study recruited 5,276 1-year-old infants in Melbourne, Australia, with repeat assessments at ages 6 and 10 years. At ages 6 and 10 years, carers completed a questionnaire on symptoms and doctor diagnosis of allergic conditions (International Study of Asthma and Allergies in Children). Children were invited to attend a clinic assessment including skin prick test, lung function tests, and oral food challenges when indicated. To minimize the impact of attrition bias, prevalence estimates among participants at ages 6 and 10 years were weighted to reflect characteristics of the whole cohort at recruitment.

RESULTS

In total, 4,455 and 4,065 families participated at ages 6 and 10 years, respectively (84% and 77% of the original cohort). Of those, 73% and 55% of participants ages 6 and 10 years, respectively, completed clinical assessments. Overall, 36.5% (95% CI, 34.8-38.2) and 38.2% (95% CI, 36.5-40.1%) of 6- and 10-year-olds had at least one current allergic disease, and around one third of those had two or more allergic diseases. Food allergy occurred in 6.4% (95% CI, 5.6-7.2) of 6-year olds and 6.3% (95% CI, 5.5-7.2) of 10-year-olds. Among infants with challenge-confirmed food allergy in infancy, 45% had persistent disease at age 10 years. The prevalence of current diagnosed asthma at ages 6 and 10 years were 12.1% (95% CI, 10.9-13.3) and 13.1% (95% CI, 11.9-14.4), respectively, current eczema decreased slightly from 15.3% (95% CI, 14.1-19.7) at age 6 years to 12.9% (95% CI, 11.7-14.2) at age 10 years, and current rhinitis increased from 15.1% (95% CI, 13.9-16.5) at age 6 years to 25.0% (95% CI, 23.4-26.7) at age 10 years.

CONCLUSIONS

Allergic diseases affect 40% of primary school-age children; one third have multiple allergic diagnoses. Challenge-confirmed food allergy prevalence remains high, and 45% of infants with food allergy have persistent disease to age 10 years.

Interaction Between Baseline Participant Factors and Treatment Effects Following Peanut Oral Immunotherapy

BACKGROUND

The Probiotic Peanut Oral Immunotherapy-003 multicenter randomized trial found that both probiotic peanut oral immunotherapy (PPOIT) and peanut OIT alone (OIT) were effective compared with placebo in inducing clinical remission after 18 months of treatment, and improving health-related quality of life (HRQL) at 12 months after treatment. Understanding treatment effect modifiers can optimize outcomes through precision care.

OBJECTIVES

This post hoc study examined baseline clinical and demographic participant factors that modified treatment effects.

METHODS

The study sample included 201 children (aged 1-10 years) with challenge-confirmed peanut allergy. Exposure variables were baseline clinical and demographic factors. Outcomes were remission (double-blind, placebo-controlled food challenge, cumulative 4,950-mg peanut protein at 8 weeks after treatment) and HRQL (change in Food Allergy Quality of Life Questionnaire-Parent Form score). Interactions between baseline factors and treatment effects on remission and HRQL were explored with regression models.

RESULTS

A higher degree of peanut sensitivity (large peanut skin prick test, high peanut specific IgE, and low reaction-eliciting dose at study entry challenge) and other concurrent allergic conditions (multiple food allergies, asthma, or wheeze) were associated with the decreased likelihood of attaining remission after both PPOIT and OIT treatment. History of anaphylaxis was associated with the reduced likelihood of remission after PPOIT compared with OIT. For the HRQL outcome, there was evidence that sex, history of anaphylaxis, and age modified treatment effects.

CONCLUSIONS

Baseline participant factors modify PPOIT and OIT effects on remission and HRQL. Considering modifiers of treatment effect during participant selection may optimize treatment success and clinical trial design toward specific outcomes, such as the achievement of remission.

Differential anti-viral response to respiratory syncytial virus A in preterm and term infants

BACKGROUND

Preterm infants are more likely to experience severe respiratory syncytial virus (RSV) disease compared to term infants. The reasons for this are multi-factorial, however their immature immune system is believed to be a major contributing factor.

METHODS

We collected cord blood from 25 preterm (gestational age 30.4-34.1 weeks) and 25 term infants (gestation age 37-40 weeks) and compared the response of cord blood mononuclear cells (CBMCs) to RSVA and RSVB stimulation using neutralising assays, high-dimensional flow cytometry, multiplex cytokine assays and RNA-sequencing.

FINDINGS

We found that preterm and term infants had similar maternally derived neutralising antibody titres to RSVA and RSVB. Preterm infants had significantly higher myeloid dendritic cells (mDC) RSV infection compared to term infants. Differential gene expression analysis of RSVA stimulated CBMCs revealed enrichment of genes involved in cytokine production and immune regulatory pathways involving IL-10, IL-36γ, CXCL1, CXCL2, SOCS1 and SOCS3 in term infants, while differentially expressed genes (DEGs) in preterm infants were related to cell cycle (CDK1, TTK, ESCO2, KNL1, CDC25A, MAD2L1) without associated expression of immune response genes. Furthermore, enriched genes in term infants were highly correlated suggesting an increased co-ordination of their immune response to RSVA. When comparing DEGs in preterm and term infants following RSVB stimulation, no differences in immune response genes were identified.

INTERPRETATION

Overall, our data suggests that preterm infants have a more restricted immunological response to RSVA compared with term infants. While further studies are required, these findings may help to explain why preterm infants are more susceptible to severe RSV disease and identify potential therapeutic targets to protect these vulnerable infants.

FUNDING

Murdoch Children's Research Institute Infection and Immunity theme grant.

Preparing Patients for Oral Immunotherapy (PPOINT): International Delphi consensus for procedural preparation and consent

BACKGROUND

Despite the promise of oral immunotherapy (OIT) to treat food allergies, this procedure is associated with potential risk. There is no current agreement about what elements should be included in the preparatory or consent process.

OBJECTIVE

We developed consensus recommendations about the OIT process considerations and patient-specific factors that should be addressed before initiating OIT and developed a consensus OIT consent process and information form.

METHODS

We convened a 36-member Preparing Patients for Oral Immunotherapy (PPOINT) panel of allergy experts to develop a consensus OIT patient preparation, informed consent process, and framework form. Consensus for themes and statements was reached using Delphi methodology, and the consent information form was developed.

RESULTS

The expert panel reached consensus for 4 themes and 103 statements specific to OIT preparatory procedures, of which 76 statements reached consensus for inclusion specific to the following themes: general considerations for counseling patients about OIT; patient- and family-specific factors that should be addressed before initiating OIT and during OIT; indications for initiating OIT; and potential contraindications and precautions for OIT. The panel reached consensus on 9 OIT consent form themes: benefits, risks, outcomes, alternatives, risk mitigation, difficulties/challenges, discontinuation, office policies, and long-term management. From these themes, 219 statements were proposed, of which 189 reached consensus, and 71 were included on the consent information form.

CONCLUSION

We developed consensus recommendations to prepare and counsel patients for safe and effective OIT in clinical practice with evidence-based risk mitigation. Adoption of these recommendations may help standardize clinical care and improve patient outcomes and quality of life.

Transcriptomic changes associated with oral immunotherapy for food allergy

This review summarizes recent advances in characterizing the transcriptional pathways associated with outcomes following Oral Immunotherapy. Recent technological advances including single-cell sequencing are transforming the ways in which the transcriptional landscape is understood. The application of these technologies is still in its infancy in food allergy but here we summarize current understanding of gene expression changes following oral immunotherapy for food allergy and specific signatures underpinning the different clinical outcomes of desensitization and remission (sustained unresponsiveness). T helper 2A cells have been identified as a cell type which correlates with disease activity and is modified by treatment. Molecular features at study entry may differentiate individuals who achieve more positive outcomes during OIT. Recent findings point to T cell anergy and Type 1 interferon pathways as potential mechanisms supporting redirection of the allergen-specific immune response away from allergy towards remission. Despite these developments in our understanding of immune mechanisms following OIT, there are still significant gaps. Additional studies examining immune signatures associated with long term and well-defined clinical outcomes are required to gain a more complete understanding of the pathways leading to remission of allergy, in order to optimize treatments and gain improved outcomes for patients.

Associations between gender and health-related quality of life in people with IgE-mediated food allergy and their caregivers: A systematic review

OBJECTIVE

Understanding factors that impact health-related quality of life (HRQL) is essential to inform personalised food allergy management. However, there are inconsistencies about the impact of gender on HRQL in food allergy. This review aimed to collate all investigations of the association between gender and total or subdomain HRQL scores of individuals with food allergy and their caregivers.

DESIGN

This is a narrative systematic review. We descriptively synthesised and compared HRQL outcomes by participant and parent genders according to statistical and clinical significance. Study quality was assessed using the ROBINS-I, inclusive of all domains. Sensitivity analysis of non-interventional studies was conducted using the ROBINS-E.

DATA SOURCES

A systematic search of Medline and Embase databases was conducted on 4 April 2022 and updated on 5 December 2023.

ELIGIBILITY CRITERIA

Studies were eligible for inclusion if they reported original data on the association between any sex and/or gender and HRQL, as measured with any validated instrument, in populations with IgE-mediated food allergy. Interventional and non-interventional studies were eligible.

RESULTS

A comparison of 34 eligible studies (10 interventional and 24 non-interventional) indicated females with food allergy (62.5% of studies of children, 83.3% of studies of adults) and mothers of children with food allergy (50% of studies of caregivers) experienced poorer self-reported baseline HRQL than their counterparts, notably in domains of physical, emotional or food anxiety-related well-being. Gender differences in child HRQL after food allergen immunotherapy were observed. However, selective reporting in included interventional studies meant the direction of this association could not be determined. The proxy-reported total HRQL of participants was not affected by caregiver gender, nor was caregiver HRQL likely impacted by child gender.

CONCLUSIONS

Gender should be considered an important modifier of participant HRQL outcomes in food allergy studies. Purposeful exploration of HRQL in all genders is needed to fully understand the implications of this construct on the lived experience of food allergy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO (CRD42022329901).

Emotional symptoms and inflammatory biomarkers in childhood: Associations in two Australian birth cohorts

BACKGROUND

An increasing body of evidence supports associations between inflammation and mental health difficulties, but the onset and directionality of these relationships are unclear.

METHODS

Data sources: Barwon Infant Study (BIS; n = 500 4-year-olds) and Longitudinal Study of Australian Children (LSAC; n = 1099 10-13-year-olds).

MEASURES

Strengths and Difficulties Questionnaire emotional symptoms at 4, 10-11 and 12-13 years, and circulating levels of two inflammatory biomarkers, high-sensitivity C-reactive protein (hsCRP) and glycoprotein acetyls (GlycA), at 4 and 11-12 years.

ANALYSIS

Adjusted quantile regression models examining cross-sectional associations between emotional symptoms and inflammation in 4-year-olds (BIS), and cross-lagged associations in 10-13-year-olds (LSAC).

RESULTS

We identified a small association between higher emotional symptoms at 10-11 years and higher GlycA levels a year later (standardised coefficient β = 0.09; 95%CI: 0.02 to 0.15). Sex-stratified analyses revealed this association was stronger for boys (β = 0.13; 95%CI: 0.04 to 0.21) than girls (β = 0.01; 95%CI: -0.09 to 0.11). These associations were not observed for hsCRP. There was little evidence of an association between higher GlycA or hsCRP at 11-12 years and emotional symptoms a year later, or cross-sectional associations between emotional symptoms and hsCRP or GlycA at 4 years.

LIMITATIONS

A single time-point of biomarker collection in late childhood precluded adjustment for baseline inflammatory biomarkers.

CONCLUSIONS

Our results support the direction of association from emotional symptoms to inflammation in late childhood, with potential sex differences. This adds to the body of evidence that addressing emotional symptoms in childhood is a major priority in optimising overall health throughout the life course.

Effects of prenatal alcohol exposure on infant lung function, wheeze, and respiratory infections in Australian children

BACKGROUND

Prenatal alcohol exposure (PAE) is a known risk factor for a range of adverse outcomes, such as facial dysmorphism, adverse birth outcomes, and neurodevelopmental changes. Preclinical research shows that PAE also inhibits lung development, lowers surfactant protein expression, has detrimental effects on alveolar macrophages, and decreases both T and B cell numbers. However, clinical evidence of respiratory impacts from PAE is limited. This study explored whether lung function, wheeze, and incidence of respiratory infections differ in children with PAE compared with unexposed children.

METHODS

Data from the Barwon Infant Study (n = 1074) were examined. PAE data were extracted from maternal questionnaires at trimesters 1 and 2 (combined), and trimester 3, and included as "total standard drinks" during each trimester and total pregnancy intake, a binary yes/no for PAE, and binge drinking (>5 standard drinks in one session). Respiratory outcomes were parent-reported wheeze, lung function (measured by multiple breath washout), and parent report and medical record indicators of health service attendances for respiratory conditions. Linear and logistic regressions were performed to quantify relationships between PAE and respiratory outcomes, controlling for socioeconomic status, birthweight, sex, gestational age, and maternal smoking.

RESULTS

Binge drinking was associated with increased health service attendance for respiratory condition(s) in the first 12 months of life (OR = 5.0, 95% CI (1.7, 20.7), p = 0.008). We did not find a relationship between binary PAE and binge drinking with lung function at 4 weeks of age or wheeze at 12 months. The number of standard drinks consumed in trimester two was associated with a lower lung clearance index (β = -0.011 turnovers, 95% CI (-0.0200, -0.0013), p = 0.03), and a small increase in functional residual capacity (β = 0.34 mL, 95% CI (0.02, 0.66), p = 0.04).

CONCLUSIONS

We found an association between binge drinking and health service utilization for respiratory conditions in infancy, but no evidence that low-level PAE was associated with adverse respiratory outcomes.

Association of Reaction Symptoms and Eliciting Dose With Health-Related Quality of Life in Children With Peanut Allergy

BACKGROUND

Food allergy adversely affects the health-related quality of life (HRQoL) of patients. It is unclear whether factors such as the reaction eliciting dose (ED) and the nature of allergic reaction symptoms affect HRQoL.

OBJECTIVE

To explore associations between reaction ED or the nature of allergic symptoms and HRQoL among children with peanut allergy.

METHODS

This study was a secondary analysis of baseline data from the PPOIT-003 randomized trial in 212 children aged 1 to 10 years with challenge-confirmed peanut allergy. Children's past reaction symptoms were collected by clinicians during screening. Associations between variables of interest and parent-reported child-proxy HRQoL were examined by univariable and multivariable linear regression.

RESULTS

Mean age of study participants was 5.9 years; 63.2% were male. Children with a low reaction ED of 80 mg peanut protein had significantly poorer HRQoL (β = -0.81; 95% CI, -1.61 to -0.00; P = .049) compared with children with a high ED of 2,500 mg peanut protein. Gastrointestinal symptoms (β = 0.45; 95% CI, 0.03-0.87; P = .037), lower airway symptoms (β = 0.46; 95% CI, 0.05-0.87; P = .030), multisystem involvement (β = 0.71; 95% CI, 0.25-1.16; P = .003), or anaphylaxis (β = 0.46; 95% CI, 0.04-0.87; P = .031) during a previous reaction were associated with worse HRQoL.

CONCLUSIONS

Peanut-allergic children with a lower allergen reaction threshold experienced a greater negative HRQoL impact compared with children with higher reaction thresholds. In addition, specific past allergic reaction symptoms were associated with comparatively worse HRQoL. Children experiencing these symptoms and those with lower reaction ED require increased clinical support to manage the food allergy and are likely to benefit from interventions that can improve HRQoL.

Childhood body mass index trajectories and asthma and allergies: A systematic review

BACKGROUND

Previous systematic reviews have focused on associations between single time point measures of Body Mass Index (BMI) and asthma and allergic diseases. As BMI changes dynamically during childhood, examination of associations between longitudinal trajectories in BMI and allergic diseases is needed to fully understand the nature of these relationships.

OBJECTIVE

To systematically synthesise the association between BMI trajectories in childhood (0-18 years) and allergic diseases (asthma, eczema, allergic rhinitis, or food allergies outcomes).

DESIGN

We conducted a systematic review following the PRISMA guidelines, and two independent reviewers assessed the study quality using the ROBINS-E and GRADE tools. A narrative synthesis was performed as the statistical heterogeneity did not allow a meta-analysis.

DATA SOURCES

A search was performed on PubMed and EMBASE databases on 4th January 2023.

ELIGIBILITY CRITERIA

Longitudinal cohort studies assessing the associations between childhood BMI trajectories and allergic diseases were included.

RESULTS

Eleven studies met the inclusion criteria with a total of 37,690 participants between 0 and 53 years of age. Ten studies examined asthma outcomes, three assessed association with allergic rhinitis, two assessed eczema, and one assessed food allergy. High heterogeneity and high risk of bias were observed. Overall, the quality of evidence was very low. Nevertheless, two consistent findings were identified: (1) a persistently high BMI between 6 and 10 years of age may be associated with an increased risk of asthma at 18 years and (2) a rapid increase in BMI in the first 2 years of life may be associated with subsequent asthma.

CONCLUSIONS

Maintaining a normal BMI trajectory during childhood may reduce the risk of asthma. Future research that adequately addresses confounding and includes longer-term follow-up is needed. Moreover, additional studies examining potential associations with eczema, food allergies, and allergic rhinitis outcomes are needed.

Gut microbiota maturity mediates the protective effect of siblings on food allergy

BACKGROUND

The mechanisms underlying the protective effect of older siblings on allergic disease remain unclear but may relate to the infant gut microbiota.

OBJECTIVE

We sought to investigate whether having older siblings decreases the risk of IgE-mediated food allergy by accelerating the maturation of the infant gut microbiota.

METHODS

In a birth cohort assembled using an unselected antenatal sampling frame (n = 1074), fecal samples were collected at 1 month, 6 months, and 1 year, and food allergy status at 1 year was determined by skin prick test and in-hospital food challenge. We used 16S rRNA gene amplicon sequencing to derive amplicon sequence variants. Among a random subcohort (n = 323), microbiota-by-age z scores at each time point were calculated using fecal amplicon sequence variants to represent the gut microbiota maturation over the first year of life.

RESULTS

A greater number of siblings was associated with a higher microbiota-by-age z score at age 1 year (β  = 0.15 per an additional sibling; 95% CI, 0.05-0.24; P = .003), which was in turn associated with decreased odds of food allergy (odds ratio, 0.45; 95% CI, 0.33-0.61; P < .001). Microbiota-by-age z scores mediated 63% of the protective effect of siblings. Analogous associations were not observed at younger ages.

CONCLUSIONS

The protective effect of older siblings on the risk of developing IgE-mediated food allergy during infancy is substantially mediated by advanced maturation of the gut microbiota at age 1 year.

Infant food allergy phenotypes and association with lung function deficits and asthma at age 6 years: a population-based, prospective cohort study in Australia

BACKGROUND

Food allergy is considered a precursor to asthma in the context of the atopic march, but the relationship between infant food allergy phenotypes and lung function and asthma in childhood is unclear. We aimed to examine the association between food sensitisation and challenge-confirmed food allergy in infancy, as well as persistent and resolved food allergy up to age 6 years, and the risk of lung function deficits and asthma at age 6 years.

METHODS

The longitudinal, population-based HealthNuts cohort study in Melbourne, VIC, Australia, recruited 5276 infants children aged 1 year who attended council-run immunisation sessions between Sept 28, 2007, and Aug 5, 2011. At age 1 year, all children completed skin prick testing to four food allergens (egg, peanut, sesame, and either shrimp or cow's milk) and an oral food challenge (egg, peanut, and sesame) at the Royal Children's Hospital in Melbourne. Parents completed questionnaires about their infant's allergy history, demographic characteristics, and environmental exposures. At age 6 years, children were invited for a health assessment that included skin prick testing for ten foods (milk, egg, peanut, wheat, sesame, soy, shrimp, cashew, almond, and hazelnut) and eight aeroallergens (alternaria, cladasporum, house dust mite, cat hair, dog hair, bermuda grass, rye grass, and birch mix), oral food challenges, and lung function testing by spirometry. Questionnaires completed by parents (different to those completed at age 1 year) captured the child's allergy and respiratory history and demographics. We investigated associations between food allergy phenotypes (food-sensitised tolerance or food allergy; and ever, transient, persistent, or late-onset food allergy), lung function spirometry measures (forced expiratory volume in 1 sec [FEV1] and forced vital capacity [FVC] z-scores, FEV1/FVC ratio, forced expiratory flow at 25% and 75% of the pulmonary volume [FEF25-75%], and bronchodilator responsiveness), and asthma using regression methods. Only children with complete data on the exposure, outcome, and confounders were included in models. Infants without food sensitisation or food allergy at age 1 year and 6 years served as the reference group.

FINDINGS

Of 5276 participants, 3233 completed the health assessment at age 6 years and were included in this analysis. Food allergy, but not food-sensitised tolerance, at age 1 year was associated with reduced FEV1 and FVC (aβ -0·19 [95% CI -0·32 to -0·06] and -0·17 [-0·31 to -0·04], respectively) at age 6 years. Transient egg allergy was associated with reduced FEV1 and FVC compared with never having egg allergy (-0·18 [95% CI -0·33 to -0·03] and -0·15 [-0·31 to 0·00], respectively), whereas persistent egg allergy was not (FEV1 -0·09 [-0·48 to 0·31]; FVC -0·20 [-0·62 to 0·21]). Transient peanut allergy was associated with reduced FEV1 and FVC (FEV1 aβ -0·37 [-0·79 to 0·04] and FVC aβ -0·55 [-0·98 to -0·12]), in addition to persistent peanut allergy (FEV1 aβ -0·30 [-0·54 to -0·06] and FVC aβ-0·30 [-0·55 to -0·05]), and late-onset peanut allergy (FEV1 aβ -0·62 [-1·06 to -0·18] and FVC aβ-0·49 [-0·96 to -0·03]). Estimates suggested that food-sensitised tolerance and food allergy were associated with reduced FEF25-75%, although some estimates were imprecise. Food allergy phenotypes were not associated with an FEV1/FVC ratio. Late-onset peanut allergy was the only allergy phenotype that was possibly associated with increased risk of bronchodilator responsiveness (2·95 [95% CI 0·77 to 11·38]). 430 (13·7%) of 3135 children were diagnosed with asthma before age 6 years (95% CI 12·5-15·0). Both food-sensitised tolerance and food allergy at age 1 year were associated with increased asthma risk at age 6 years (adjusted odds ratio 1·97 [95% CI 1·23 to 3·15] and 3·69 [2·81 to 4·85], respectively). Persistent and late-onset peanut allergy were associated with higher asthma risk (3·87 [2·39 to 6·26] and 5·06 [2·15 to 11·90], respectively).

INTERPRETATION

Food allergy in infancy, whether it resolves or not, is associated with lung function deficits and asthma at age 6 years. Follow-up studies of interventions to prevent food allergy present an opportunity to examine whether preventing these food allergies improves respiratory health.

FUNDING

National Health & Medical Research Council of Australia, Ilhan Food Allergy Foundation, AnaphylaxiStop, the Charles and Sylvia Viertel Medical Research Foundation, the Victorian Government's Operational Infrastructure Support Program.

Updated guidance regarding the risk of allergic reactions to COVID-19 vaccines and recommended evaluation and management: A GRADE assessment and international consensus approach

This guidance updates 2021 GRADE (Grading of Recommendations Assessment, Development and Evaluation) recommendations regarding immediate allergic reactions following coronavirus disease 2019 (COVID-19) vaccines and addresses revaccinating individuals with first-dose allergic reactions and allergy testing to determine revaccination outcomes. Recent meta-analyses assessed the incidence of severe allergic reactions to initial COVID-19 vaccination, risk of mRNA-COVID-19 revaccination after an initial reaction, and diagnostic accuracy of COVID-19 vaccine and vaccine excipient testing in predicting reactions. GRADE methods informed rating the certainty of evidence and strength of recommendations. A modified Delphi panel consisting of experts in allergy, anaphylaxis, vaccinology, infectious diseases, emergency medicine, and primary care from Australia, Canada, Europe, Japan, South Africa, the United Kingdom, and the United States formed the recommendations. We recommend vaccination for persons without COVID-19 vaccine excipient allergy and revaccination after a prior immediate allergic reaction. We suggest against >15-minute postvaccination observation. We recommend against mRNA vaccine or excipient skin testing to predict outcomes. We suggest revaccination of persons with an immediate allergic reaction to the mRNA vaccine or excipients be performed by a person with vaccine allergy expertise in a properly equipped setting. We suggest against premedication, split-dosing, or special precautions because of a comorbid allergic history.

Efficacy and safety of oral immunotherapy for peanut, cow's milk, and hen's egg allergy: A systematic review of randomized controlled trials

BACKGROUND

Oral immunotherapy (OIT) is a promising treatment for food allergies; however, safety is a concern. We synthesized evidence from the best randomized controlled trials (RCTs) on efficacy/safety of OIT for desensitization (DS) and remission (sustained unresponsiveness (SU)) in IgE mediated allergy to peanut, hen's eggs, and cow's milk. BODY: We searched Pubmed, EMBASE, and Cochrane databases (Until Oct 22) identifying 16 eligible RCTs published in English measuring food allergy by food challenge at the beginning and at the end of the study. The Cochrane Risk of Bias tool was used to assess study quality. We found 18 eligible studies. There was evidence of efficacy for DS for all allergens: peanut (RR 11.32; 95% CI 5.93, 21.60, I² 49%, 8 studies); hen's egg (RR 4.67; 2.66, 8.21, I² 0%, 5 studies); cow's milk (RR 13.98; 3.51, 55.65, I² 0%, 4 studies) and evidence for SU for peanut (RR 7.74; 2.90, 20.69, I² 0%, 3 studies) and hen's egg (RR 6.91; 1.67, 28.57, I² 0%, 2 studies). Allergic events were increased with intervention, and risk of adrenaline use increased for peanut RR 2.96; 1.63, 5.35, I² 0%, 8 studies; egg RR 1.71; 0.42, 6.92, I² 0%, 6 studies; and milk RR 8.45; 2.02, 35.27, I² 0%, 4 studies.

CONCLUSION

We found strong evidence that peanut, hen's egg, and cow's milk OIT can induce DS and some evidence for remission. There was a high risk of allergic reactions. Generalizability to the entire food allergic population is not known.

Understanding the pathways between prenatal and postnatal factors and overweight outcomes in early childhood: a pooled analysis of seven cohorts

BACKGROUND/OBJECTIVES

Childhood overweight and obesity are influenced by a range of prenatal and postnatal factors. Few studies have explored the integrative pathways linking these factors and childhood overweight. This study aimed to elucidate the integrative pathways through which maternal pre-pregnancy body mass index (BMI), infant birth weight, breastfeeding duration, and rapid weight gain (RWG) during infancy are associated with overweight outcomes in early childhood from ages 3 to 5 years.

SUBJECTS/METHODS

Pooled data from seven Australian and New Zealand cohorts were used (n = 3572). Generalized structural equation modelling was used to examine direct and indirect associations of maternal pre-pregnancy BMI, infant birth weight, breastfeeding duration, and RWG during infancy with child overweight outcomes (BMI z-score and overweight status).

RESULTS

Maternal pre-pregnancy BMI was directly associated with infant birth weight (β 0.01, 95%CI 0.01, 0.02), breastfeeding duration ≥6 months (OR 0.92, 95%CI 0.90, 0.93), child BMI z-score (β 0.03, 95%CI 0.03, 0.04) and overweight status (OR 1.07, 95%CI 1.06, 1.09) at ages 3-5 years. The association between maternal pre-pregnancy BMI and child overweight outcomes was partially mediated by infant birth weight, but not RWG. RWG in infancy exhibited the strongest direct association with child overweight outcomes (BMI z-score: β 0.72, 95%CI 0.65, 0.79; overweight status: OR 4.49, 95%CI 3.61, 5.59). Infant birth weight was implicated in the indirect pathways of maternal pre-pregnancy BMI with RWG in infancy, breastfeeding duration, and child overweight outcomes. The associations between breastfeeding duration (≥6 months) and lower child overweight outcomes were fully mediated by RWG in infancy.

CONCLUSIONS

Maternal pre-pregnancy BMI, infant birth weight, breastfeeding duration and RWG in infancy act in concert to influence early childhood overweight. Future overweight prevention interventions should target RWG in infancy, which showed the strongest association with childhood overweight; and maternal pre-pregnancy BMI, which was implicated in several pathways leading to childhood overweight.

Biomarkers of asthma relapse and lung function decline in adults with spontaneous asthma remission: A population-based cohort study

BACKGROUND

The extent to which biomarkers of asthma activity persist in spontaneous asthma remission and whether such markers are associated with future respiratory outcomes remained unclear. We investigated the association between sub-clinical inflammation in adults with spontaneous asthma remission and future asthma relapse and lung function decline.

METHODS

The Tasmanian Longitudinal Health Study is a population-based cohort (n = 8583). Biomarkers of systemic inflammation were measured on participants at age 45, and latent profile analysis was used to identify cytokine profiles. Bronchial hyperresponsiveness (BHR) and nitric oxide products in exhaled breath condensate (EBC NOx) were measured at age 50. Participants with spontaneous asthma remission at ages 45 (n = 466) and 50 (n = 318) were re-evaluated at age 53, and associations between baseline inflammatory biomarkers and subsequent asthma relapse and lung function decline were assessed.

RESULTS

We identified three cytokine profiles in adults with spontaneous asthma remission: average (34%), Th2-high (42%) and Th2-low (24%). Compared to the average profile, a Th2-high profile was associated with accelerated decline in post-BD FEV1 /FVC (MD -0.18% predicted per-year; 95% CI -0.33, -0.02), while a Th2-low profile was associated with accelerated decline in both post-BD FEV1 (-0.41%; -0.75, -0.06) and post-BD FVC (-0.31%; -0.62, 0.01). BHR and high TNF-α during spontaneous remission were associated with an increased risk of asthma relapse. In contrast, we found no evidence of association between EBC NOx and either asthma relapse or lung function decline.

CONCLUSION

BHR and serum inflammatory cytokines have prognostic value in adults with spontaneous asthma remission. At-risk individuals with BHR, Th2-high or Th2-low cytokine profiles may benefit from closer monitoring and on-going follow-up.

The Short Food Allergy Quality of Life Questionnaire (FAQLQ-12) for Adults

BACKGROUND

The Food Allergy Quality of Life Questionnaire (FAQLQ) is the most widely used measure to assess health-related quality of life in food allergy. However, its length can lead to a series of disadvantages, such as reduced or incomplete participation and boredom and disengagement, affecting data quality, reliability, and validity.

OBJECTIVE

We shortened the well-known FAQLQ for adults and propose the FAQLQ-12.

METHODS

We applied reference-standard statistical analyses, mixing classic test theory and item response theory to identify relevant items for the new short form and confirm its structure fit and reliability. More specifically, we employed discrimination, difficulty, and information levels (item response theory), confirmatory factor analysis, Pearson's correlations, and reliability analysis (McDonald ω and Cronbach α).

RESULTS

We chose items with the highest discrimination values to compose the shortened FAQLQ because they were among the ones with the best difficulty levels and the highest amount of individual information. We retained three items per factor because this number allowed for acceptable reliability levels, resulting in 12 items. The FAQLQ-12 presented a better model fit compared with the complete version. The correlation patterns and reliability levels were similar for both the 29 and 12 versions.

CONCLUSIONS

Although the full version of the FAQLQ remains a reference standard to assess food allergy quality of life, the FAQLQ-12 is introduced as a powerful and beneficial alternative. It can help participants, researchers, and clinicians in specific settings, such as dealing with time and budget limitations, and provides high-quality and reliable responses.

Varying Approaches to Management of IgE-Mediated Food Allergy in Children Around the World

Food allergy is a chronic disease that affects individuals of all ages and is a significant public health problem globally. This narrative overview examines clinical management strategies for IgE-mediated food allergy in children around the world to understand variations in practice. Information was drawn from clinical practice guidelines, recent research, the websites of professional and governmental bodies with expertise in food allergy, and clinical experts from a broad cross-section of geographical regions. The structure and delivery of clinical services, allergen avoidance and food labeling, and resources to support the management of allergic reactions in the community are discussed in detail. The adoption of emerging food immunotherapies is also explored. Wide variations in clinical management of food allergy were apparent across the different countries. Common themes were continuing issues with access to specialist care and recognition of the need to balance risk reduction with dietary and social restrictions to avoid unnecessary detrimental impacts on the quality of life of food allergy sufferers. Findings highlight the need for standardized presentation of practice and priorities, and may assist clinicians and researchers when engaging with government and funding agencies to address gaps.

Endpoints and Outcomes After Immunotherapy for Food Allergy: What Is Meaningful for Patients?

Multiple novel interventions for food allergy are currently at various stages of development with the goal of reducing or eliminating allergic reactions. However, the relative success of these therapeutics in achieving meaningful, long-term improvements to patients' lives is difficult to determine as there is currently very limited understanding of the degree of alignment between clinical trial efficacy endpoints and patient-centered outcomes. Furthermore, outcome measures used in clinical trials of food allergy immunotherapies vary widely, are often misinterpreted, and not necessarily consistent with what patients expect to achieve through treatment. This review aims to assist clinicians in critically interpreting outcomes reported in clinical trials and accurately communicating risks and outcomes to patients when practicing shared decision-making.

Epidemiology of eczema in South-Eastern Australia

BACKGROUND/OBJECTIVES

Eczema is a common chronic debilitating skin condition in childhood. Data on the epidemiology and natural history of eczema across the life course are lacking. This analysis aimed to describe these epidemiological features in Australian children and adults.

METHODS

Data collected on eczema from four Australian cohort studies were analysed: namely HealthNuts, Melbourne Atopic Cohort Study (MACS), Tasmanian Longitudinal Health Study (TAHS) and the Australian arm of the European Community Respiratory Health Survey (ECRHS).

RESULTS

Among children aged under 6 years, 28.8%-35.6% have ever-had eczema, and 16.7%-26.6% had 'current eczema'. Among those aged 6-12 years, 14.6%-24.7% had 'current eczema' with 12.0%-18.5% of those at ages of 6 and 10 years classified as having moderate-to-severe eczema according to the Scoring of Atopic Dermatitis (SCORAD) index. In adults, the prevalence of 'eczema ever' ranged between 13.8% and 48.4%. The 12-month period prevalence of eczema was 15.1% at age 18, while current eczema was 8.5% at an average age of 51, and 8.8% at an average age 53 years. Eczema was more common among young boys, but this difference became non-significant for older children and early adolescents. In contrast, eczema was more common for adult women than men.

CONCLUSIONS

Eczema is common both in children and adults. The proportion of severe eczema in children was substantial.

Food Allergy and Eosinophilic Gastrointestinal Diseases-The Next 10 Years

The first report of food allergy desensitization was in 1908, at least a few years before the first published description of a diagnostic test for food allergy. It has taken almost 100 years for food allergy to move from passive management of avoidance to a more proactive approach including prevention and treatment. In parallel, this has been matched by recognition of eosinophil gastrointestinal diseases, which were first described in the 1980s (although eosinophilic esophagitis was itself described in 1978). As we celebrate 10 years of The Journal of Allergy and Clinical Immunology: In Practice, we take the opportunity to look into the future and speculate how our practice may develop over the next decade.

Out-of-hospital health care costs of childhood food allergy in Australia: A population-based longitudinal study

BACKGROUND

Australia has one of the highest prevalence of childhood food allergy in the world, but there are no data on its economic burden in Australia.

METHODS

We used data from the HealthNuts study, a population-based longitudinal study undertaken in Melbourne, Australia. Infants were recruited at age 12 months between Sept 2007 and Aug 2011 with food allergy diagnosed using oral food challenges. Health care costs of out-of-hospital services were collected through data linkage to Australia's universal health insurance scheme Medicare. Two-part model was used to compare costs after controlling for potential confounders.

RESULTS

2919 children were included, and 390 (13.4%) had challenge-confirmed food allergy at age 1 year. Compared with children without food allergy, children with food allergy had significantly higher costs for GP visits, specialist visits, tests, and prescriptions in the first four years of life. The total Medicare cost associated with food allergy from age 1 to 4 years was estimated to be AUD$889.7 (95% CI $566.1-$1188.3) or €411.0 (95% CI €261.5-€549.0) per child. This was projected into an annual Medicare cost of AUD$26.1 million (95% CI $20.1-$32.3 million) or €12.1 (95% CI €9.3-€14.9 million) based on population size in 2020.

CONCLUSIONS

Childhood food allergy causes considerable Medicare costs for out-of-hospital services in the first four years after birth in Australia. These findings can help anticipate the financial impact on the health care system associated with childhood food allergy, act as a useful costing resource for future evaluations, and inform management of childhood food allergy internationally.

Immuno-epigenomic analysis identifies attenuated interferon responses in naïve CD4 T cells of adolescents with peanut and multi-food allergy

BACKGROUND

IgE-mediated food allergies have been linked to suboptimal naïve CD4 T (nCD4T) cell activation in infancy, underlined by epigenetic and transcriptomic variation. Similar attenuated nCD4T cell activation in adolescents with food allergy have also been reported, but these are yet to be linked to specific epigenetic or transcriptional changes.

METHODS

We generated genome-wide DNA methylation data in purified nCD4 T cells at quiescence and following activation in a cohort of adolescents (aged 10-15 years old) with peanut allergy (peanut only or peanut + ≥1 additional food allergy) (FA, n = 29), and age-matched non-food allergic controls (NA, n = 18). Additionally, we assessed transcriptome-wide gene expression and cytokine production in these cells following activation.

RESULTS

We found widespread changes in DNA methylation in both NA and FA nCD4T cells in response to activation, associated with the T cell receptor signaling pathway. Adolescents with FA exhibit unique DNA methylation signatures at quiescence and post-activation at key genes involved in Th1/Th2 differentiation (RUNX3, RXRA, NFKB1A, IL4R), including a differentially methylated region (DMR) at the TNFRSF6B promoter, linked to Th1 proliferation. Combined analysis of DNA methylation, transcriptomic data and cytokine output in the same samples identified an attenuated interferon response in nCD4T cells from FA individuals following activation, with decreased expression of several interferon genes, including IFN-γ and a DMR at a key downstream gene, BST2.

CONCLUSION

We find that attenuated nCD4T cell responses from adolescents with food allergy are associated with specific epigenetic variation, including disruption of interferon responses, indicating dysregulation of key immune pathways that may contribute to a persistent FA phenotype. However, we recognize the small sample size, and the consequent restraint on reporting adjusted p-value statistics as limitations of the study. Further study is required to validate these findings.

The role of short-term grass pollen exposure in food skin-prick test reactivity, food allergy, and eczema flares in children

BACKGROUND

While the relationship between pollen and respiratory allergies is well-documented, the role of short-term pollen exposure in food allergy and eczema flares has not previously been explored. We aimed to investigate these associations in a population-based sample of children.

METHODS

We investigated 1- (n = 1108) and 6-year-old (n = 675) children in the grass pollen season from the HealthNuts cohort. Grass pollen concentrations were considered on the day of testing (lag 0), up to three days before (lag 1-lag 3) and cumulatively (lag 0-3). Associations between grass pollen and food skin-prick test reactivity (SPT ≥ 2 mm at age 1 year and ≥ 3 mm at age 6 years), eczema flares, challenge-confirmed food allergy, reaction threshold to oral food challenges (OFC), and serum food-specific IgE levels were analyzed using either logistic or quantile regression models. Atopy and family history of allergic disease were considered as potent effect modifiers.

RESULTS

Grass pollen at lag 0-3 (every 20 grains/m³ increase) was associated with an up to 1.2-fold increased odds of food SPT reactivity and eczema flares in 6-year-olds. In 1-year-olds, the associations were only observed for peanut in those with a family history of food allergy. Increasing grass pollen concentrations were associated with a lower reaction threshold to OFC and higher serum IgE levels in peanut-allergic 1-year-olds only.

CONCLUSION

Increasing grass pollen concentration was associated with increased risk of food SPT reactivity and eczema flares in children. The associations in peanut-allergic infants may be related to immune activation and/or peanut and grass pollen cross-reactivity leading to a lower reaction threshold.

Determinants of rapid infant weight gain: A pooled analysis of seven cohorts

OBJECTIVE

Rapid weight gain (RWG) in infancy is strongly associated with subsequent obesity risk, but little is known about the factors driving RWG. This study explored the child and maternal factors associated with infant RWG.

METHODS

Data from seven Australian and New Zealand cohorts were used (n = 4542). Infant RWG was defined as a change in weight z-score ≥0.67 from birth to age 1 year. Univariable and multivariable logistic regression assessed the association between child and maternal factors and infant RWG in each cohort. Meta-analysis was conducted to obtain pooled effect sizes.

RESULTS

Multivariable analyses revealed boys were more likely to experience RWG (OR 1.42 95% CI 1.22, 1.66) than girls. Higher birth weight in kg (OR 0.09, 95% CI 0.04, 0.20) and gestational age in weeks (OR 0.69, 95% CI 0.48, 0.98) were associated with lower RWG risk. Children who were breastfed for ≥6 months showed lower RWG risk (OR 0.45, 95% CI 0.38, 0.53). Children of native-born versus overseas-born women appeared to have higher RWG risk (OR 1.37, 95% CI 0.99, 1.90). Maternal smoking during pregnancy increased RWG risk (OR 1.60, 95% CI 1.28, 2.01), whereas children who started solids ≥6 months (OR 0.77, 95% CI 0.63, 0.93) and children with siblings (OR 0.68, 95% CI 0.57, 0.81) showed lower RWG risk in univariable analysis, but these associations were attenuated in multivariable analysis. No association was found for maternal age, education, marital status and pre-pregnancy BMI.

CONCLUSION

Maternal country of birth, smoking status, child sex, birth weight, gestational age, infant feeding and parity were potential determinants of infant RWG.

Remission of peanut allergy is associated with rewiring of allergen-driven T helper 2-related gene networks

BACKGROUND

The immunological changes underpinning acquisition of remission (also called sustained unresponsiveness) following food immunotherapy remain poorly defined. Limited access to effective therapies and biosamples from treatment responders has prevented progress. Probiotic peanut oral immunotherapy is highly effective at inducing remission, providing an opportunity to investigate immune changes.

METHODS

Using a systems biology approach, we examined gene co-expression network patterns in peanut-specific CD4⁺ T cell responses before and after probiotic and peanut oral immunotherapy in subjects enrolled in the PPOIT-001 randomized trial: Responders who attained remission (n = 16), placebo-treated who remained allergic (n = 16).

RESULTS

Acquisition of remission was associated with rewiring of gene network patterns, which was characterized by integration of T helper 2 and interferon signalling modules, markedly reduced T helper 2 gene connectivity, and shutdown in co-expression activity between T helper 2 effectors and cell cycle regulators.

CONCLUSION

The immunological changes underlying remission following peanut oral immunotherapy are mediated by reprogramming of T helper 2-associated gene networks in the CD4⁺ T cell compartment. Findings provide insight into immune mechanisms driving the acquisition of remission following oral immunotherapy, paving the way for the development of improved approaches to induce remission/sustained unresponsiveness in patients with food allergy.

Maternal gut microbiota during pregnancy and the composition of immune cells in infancy

Background

Preclinical studies have shown that maternal gut microbiota during pregnancy play a key role in prenatal immune development but the relevance of these findings to humans is unknown. The aim of this prebirth cohort study was to investigate the association between the maternal gut microbiota in pregnancy and the composition of the infant’s cord and peripheral blood immune cells over the first year of life.

Methods

The Barwon Infant Study cohort (n=1074 infants) was recruited using an unselected sampling frame. Maternal fecal samples were collected at 36 weeks of pregnancy and flow cytometry was conducted on cord/peripheral blood collected at birth, 6 and 12 months of age. Among a randomly selected sub-cohort with available samples (n=293), maternal gut microbiota was characterized by sequencing the 16S rRNA V4 region. Operational taxonomic units (OTUs) were clustered based on their abundance. Associations between maternal fecal microbiota clusters and infant granulocyte, monocyte and lymphocyte subsets were explored using compositional data analysis. Partial least squares (PLS) and regression models were used to investigate the relationships/associations between environmental, maternal and infant factors, and OTU clusters.

Results

We identified six clusters of co-occurring OTUs. The first two components in the PLS regression explained 39% and 33% of the covariance between the maternal prenatal OTU clusters and immune cell populations in offspring at birth. A cluster in which Dialister, Escherichia, and Ruminococcus were predominant was associated with a lower proportion of granulocytes (p=0.002), and higher proportions of both central naïve CD4⁺ T cells (CD4⁺/CD45RA⁺/CD31⁻) (p<0.001) and naïve regulatory T cells (Treg) (CD4⁺/CD45RA⁺/FoxP3^low) (p=0.02) in cord blood. The association with central naïve CD4⁺ T cells persisted to 12 months of age.

Conclusion

This birth cohort study provides evidence consistent with past preclinical models that the maternal gut microbiota during pregnancy plays a role in shaping the composition of innate and adaptive elements of the infant’s immune system following birth.

A pragmatic approach to infant feeding for food allergy prevention

Early introduction of allergenic foods into an infant's diet is currently the most promising strategy to prevent food allergy, with infant guidelines around the world shifting from promoting avoidance to actively encourage the introduction of allergenic foods in the infant diet. Infant feeding guidelines vary according to regional public health priorities, and knowledge gaps remain, resulting in ongoing challenges for clinicians and families to translate guidelines into practical strategies for the introduction of complementary foods for food allergy prevention. Evidence from Australia demonstrates high community support and uptake of revised guidelines with most parents introducing allergenic foods in the first year of life, although this has not had the expected impact on substantially reducing food allergy prevalence. To uptake of guidelines from other countries is less clear, and several barriers have been noted in infant feeding RCTs, which may warrant intervention strategies. Further research is needed to understand additional strategies for food allergy prevention, particularly in infants who develop food allergy prior to when they are developmentally ready to commence solids. Several RCTs are underway investigating preventative strategies that target the window before allergen ingestion, such as vitamin D supplementation, emollient use, and immunizations that prime the immune response away from a Th2-driven allergic phenotype. Further research is also needed to understand the role of the environment and the host environment in the development of tolerance to foods.

Mode of Birth Is Not Associated With Food Allergy Risk in Infants

BACKGROUND

The association between mode of delivery and the risk of food allergy remains unclear due to the absence of studies with both challenge-proven food allergy outcomes and detailed information on the type of caesarean delivery.

OBJECTIVE

We assessed whether emergency or elective caesarean, or caesarean delivery in the presence or absence of labor initiation, is associated with the risk of food allergy.

METHODS

The HealthNuts study recruited 5276 12-month-old infants who underwent skin prick testing and oral food challenge to ascertain food allergy status, and linked the child's study data to additional birth data from the Victorian Perinatal Data Collection.

RESULTS

Parents of 3006 children consented to data linkage, and birth data were obtained on 2045. In this subgroup, 30% were born by caesarean and 13% had food allergy. Caesarean delivery, compared with vaginal birth, was not associated with the risk of food allergy (adjusted odds ratio [aOR]: 0.95, 95% confidence interval [CI]: 0.70, 1.30). Neither caesarean delivery before the onset of labor, nor after the onset of labor, was associated with the risk of food allergy (aOR: 0.83, 95% CI: 0.55-1.23 and aOR: 1.13, 95% CI: 0.75-1.72, respectively). Delivery by elective or emergency caesarean, compared with vaginal delivery, was not associated with risk of food allergy (aOR: 1.05, 95% CI: 0.71-1.55 and aOR: 0.86, 95% CI: 0.56-1.31). There was no evidence of effect modification by breastfeeding, older siblings, pet dog ownership, or maternal allergy.

CONCLUSION

Caesarean delivery, either with or without labor, or elective or emergency, was not associated with the risk of food allergy in a population-based cohort of 12-month-old infants.

Infant inflammation predicts childhood emotional and behavioral problems and partially mediates socioeconomic disadvantage

BACKGROUND

Emotional and behavioral problems (EBP) are common in children. Environmental factors like socioeconomic disadvantage influence EBP pathogenesis and can trigger inflammation. However, the link between early inflammation-EBP in children is unclear. We investigated the associations between i) infant inflammatory biomarkers and subsequent EBP and ii) early life environmental factors and EBP and assessed whether infant inflammation mediated these associations.

METHODS

Inflammatory biomarkers glycoprotein acetyls (GlycA) and high-sensitivity C-reactive protein (hsCRP) were quantified at birth and 12 months in a population-derived birth cohort, the Barwon Infant Study. Early life factors including demographic, prenatal, and perinatal factors were collected from antenatal to the two-year period. Internalizing and externalizing problems at age two were measured by the Child Behavior Checklist. Prospective associations were examined by multivariable regression analyses adjusted for potential confounders. Indirect effects of early life factors on EBP through inflammation were identified using mediation analyses.

RESULTS

Elevated GlycA levels at birth (GlycAbirth) were associated with greater internalizing problems at age two (β = 1.32 per SD increase in GlycA; P = 0.001). Inflammation at birth had a stronger magnitude of effect with later EBP than at 12 months. GlycAbirth partially mediated the associations between lower household income (6%), multiparity (12%) and greater number of older siblings (13%) and EBP. Patterns were less evident for hsCRP or externalizing problems.

CONCLUSIONS

GlycAbirth was positively associated with EBP at age two and partially mediated the association between several indicators of socioeconomic disadvantage and EBP. Prenatal and perinatal inflammation may be relevant to early neurodevelopment and emotional health.

Measuring the Impact of Food Immunotherapy on Health-Related Quality of Life in Clinical Trials

Food allergy is a common, and often lifelong, disorder with considerable negative impact on the quality of life of those affected and their families. While several promising immunotherapies for food allergy have either been approved or are in late-phase clinical trials based on demonstrated effectiveness at inducing desensitization, evidence of benefit in terms of improving patient-centered outcomes is inconsistent. Historically, health-related quality of life has not been prioritized as an endpoint in food immunotherapy trials and, even when included, findings have been undermined by methodological limitations of the measurement instruments used and issues with data interpretation. This review highlights the importance of measuring health-related quality of life as an endpoint in food immunotherapy trials and discusses the strengths and limitations of available evidence in this regard, with a focus on the appropriate use of assessment instruments and interpretation of findings. There remains much to learn regarding the impact of food immunotherapies on patient wellbeing, both during treatment and over the longer term. Our aim is to assist clinicians, researchers, policy makers and consumers in their interpretation of the existing literature, and to promote greater scientific rigor in the design and selection of outcome measurement frameworks for future studies evaluating the efficacy of immunotherapy treatments for food allergy.

Association Between Earlier Introduction of Peanut and Prevalence of Peanut Allergy in Infants in Australia

IMPORTANCE

Randomized clinical trials showed that earlier peanut introduction can prevent peanut allergy in select high-risk populations. This led to changes in infant feeding guidelines in 2016 to recommend early peanut introduction for all infants to reduce the risk of peanut allergy.

OBJECTIVE

To measure the change in population prevalence of peanut allergy in infants after the introduction of these new guidelines and evaluate the association between early peanut introduction and peanut allergy.

DESIGN

Two population-based cross-sectional samples of infants aged 12 months were recruited 10 years apart using the same sampling frame and methods to allow comparison of changes over time. Infants were recruited from immunization centers around Melbourne, Australia. Infants attending their 12-month immunization visit were eligible to participate (eligible age range, 11-15 months), regardless of history of peanut exposure or allergy history.

EXPOSURES

Questionnaires collected data on demographics, food allergy risk factors, peanut introduction, and reactions.

MAIN OUTCOME AND MEASURES

All infants underwent skin prick tests to peanut and those with positive results underwent oral food challenges. Prevalence estimates were standardized to account for changes in population demographics over time.

RESULTS

This study included 7209 infants (1933 in 2018-2019 and 5276 in 2007-2011). Of the participants in the older vs more recent cohort, 51.8% vs 50.8% were male; median (IQR) ages were 12.5 (12.2-13.0) months vs 12.4 (12.2-12.9) months. There was an increase in infants of East Asian ancestry over time (16.5% in 2018-2019 vs 10.5% in 2007-2011), which is a food allergy risk factor. After standardizing for infant ancestry and other demographics changes, peanut allergy prevalence was 2.6% (95% CI, 1.8%-3.4%) in 2018-2019, compared with 3.1% in 2007-2011 (difference, -0.5% [95% CI, -1.4% to 0.4%]; P = .26). Earlier age of peanut introduction was significantly associated with a lower risk of peanut allergy among infants of Australian ancestry in 2018-2019 (age 12 months compared with age 6 months or younger: adjusted odds ratio, 0.08 [05% CI, 0.02-0.36]; age 12 months compared with 7 to less than 10 months: adjusted odds ratio, 0.09 [95% CI, 0.02-0.53]), but not significant among infants of East Asian ancestry (P for interaction = .002).

CONCLUSIONS AND RELEVANCE

In cross-sectional analyses, introduction of a guideline recommending early peanut introduction in Australia was not associated with a statistically significant lower or higher prevalence of peanut allergy across the population.

Household size, T regulatory cell development, and early allergic disease: a birth cohort study

BACKGROUND

Children born to larger households have less allergic disease. T regulatory cell (Treg) development may be a relevant mechanism, but this has not been studied longitudinally.

OBJECTIVE

We aim to (i) describe how prenatal and postnatal environmental factors are associated with Treg development and (ii) investigate whether serial Treg measures predict allergic outcomes at 1 year of age.

METHODS

A birth cohort (n = 1074) with information on prenatal and postnatal early life factors. Both naïve Treg (nTreg) and activated Treg (aTreg) cell populations (as a proportion of CD4⁺ T cells) were available in 463 infants at birth (cord blood), 600 at 6 months, and 675 at 12 months. 191 infants had serial measures. Measures of allergic status at 12 months were polysensitization (sensitization to 2 or more allergens), clinically proven food allergy, atopic eczema, and atopic wheeze.

RESULTS

Infants born to larger households (3 or more residents) had higher longitudinal nTreg proportions over the first postnatal year with a mean difference (MD) of 0.67 (95% CI 0.30-1.04)%. Higher nTreg proportions at birth were associated with a reduced risk of infant allergic outcomes. Childcare attendance and breastfeeding were associated with higher longitudinal nTreg proportions (MD 0.48 (95% CI 0.08-0.80)%.

CONCLUSION

Multiple prenatal and postnatal microbial factors are associated with nTreg and aTreg development. Larger household size was associated with higher nTreg at birth which in turn was associated with reduced allergic sensitization and disease at 12 months of age.

Early life infection and proinflammatory, atherogenic metabolomic and lipidomic profiles in infancy: a population-based cohort study

Background:

The risk of adult onset cardiovascular and metabolic (cardiometabolic) disease accrues from early life. Infection is ubiquitous in infancy and induces inflammation, a key cardiometabolic risk factor, but the relationship between infection, inflammation, and metabolic profiles in early childhood remains unexplored. We investigated relationships between infection and plasma metabolomic and lipidomic profiles at age 6 and 12 months, and mediation of these associations by inflammation.

Methods:

Matched infection, metabolomics, and lipidomics data were generated from 555 infants in a pre-birth longitudinal cohort. Infection data from birth to 12 months were parent-reported (total infections at age 1, 3, 6, 9, and 12 months), inflammation markers (high-sensitivity C-reactive protein [hsCRP]; glycoprotein acetyls [GlycA]) were quantified at 12 months. Metabolic profiles were 12-month plasma nuclear magnetic resonance metabolomics (228 metabolites) and liquid chromatography/mass spectrometry lipidomics (776 lipids). Associations were evaluated with multivariable linear regression models. In secondary analyses, corresponding inflammation and metabolic data from birth (serum) and 6-month (plasma) time points were used.

Results:

At 12 months, more frequent infant infections were associated with adverse metabolomic (elevated inflammation markers, triglycerides and phenylalanine, and lower high-density lipoprotein [HDL] cholesterol and apolipoprotein A1) and lipidomic profiles (elevated phosphatidylethanolamines and lower trihexosylceramides, dehydrocholesteryl esters, and plasmalogens). Similar, more marked, profiles were observed with higher GlycA, but not hsCRP. GlycA mediated a substantial proportion of the relationship between infection and metabolome/lipidome, with hsCRP generally mediating a lower proportion. Analogous relationships were observed between infection and 6-month inflammation, HDL cholesterol, and apolipoprotein A1.

Conclusions:

Infants with a greater infection burden in the first year of life had proinflammatory and proatherogenic plasma metabolomic/lipidomic profiles at 12 months of age that in adults are indicative of heightened risk of cardiovascular disease, obesity, and type 2 diabetes. These findings suggest potentially modifiable pathways linking early life infection and inflammation with subsequent cardiometabolic risk.

Funding:

The establishment work and infrastructure for the BIS was provided by the Murdoch Children’s Research Institute (MCRI), Deakin University, and Barwon Health. Subsequent funding was secured from National Health and Medical Research Council of Australia (NHMRC), The Shepherd Foundation, The Jack Brockhoff Foundation, the Scobie & Claire McKinnon Trust, the Shane O’Brien Memorial Asthma Foundation, the Our Women’s Our Children’s Fund Raising Committee Barwon Health, the Rotary Club of Geelong, the Minderoo Foundation, the Ilhan Food Allergy Foundation, GMHBA, Vanguard Investments Australia Ltd, and the Percy Baxter Charitable Trust, Perpetual Trustees. In-kind support was provided by the Cotton On Foundation and CreativeForce. The study sponsors were not involved in the collection, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication. Research at MCRI is supported by the Victorian Government’s Operational Infrastructure Support Program. This work was also supported by NHMRC Senior Research Fellowships to ALP (1008396); DB (1064629); and RS (1045161) , NHMRC Investigator Grants to ALP (1110200) and DB (1175744), NHMRC-A*STAR project grant (1149047). TM is supported by an MCRI ECR Fellowship. SB is supported by the Dutch Research Council (452173113).

The natural history of peanut and egg allergy in children up to age 6 years in the HealthNuts population-based longitudinal study

BACKGROUND

Prospectively collected data on the natural history of food allergy are lacking.

OBJECTIVE

We examined the natural history of egg and peanut allergy in children from age 1 to 6 years and assessed whether a skin prick test (SPT) result or other clinical factors at diagnosis are associated with the persistence or resolution of food allergy in early childhood.

METHODS

The HealthNuts cohort consists of 5276 children who were recruited at age 1 year and have been followed prospectively. Children with food allergy at age 1 year (peanut [n = 156] or raw egg [n = 471] allergy ) and children who developed new sensitizations or food reactions after age 1 year were assessed for food sensitization and allergy (confirmed by oral food challenge when indicated) at the 6-year follow-up.

RESULTS

New-onset food allergy developed by age 6 years was more common for peanut (0.7% [95% CI = 0.5%-1.1%]) than egg (0.09% [95% CI = 0.03%-0.3%]). Egg allergy resolved more commonly (89% [95% CI = 85%-92%]) than peanut allergy (29% [95% CI = 22%-38%]) by age 6 years. The overall weighted prevalence of peanut allergy at age 6 years was 3.1% (95% CI = 2.6-3.7%) and that of egg allergy was 1.2% (95% = CI 0.9%-1.6%). The factors at age 1 year associated with persistence of peanut allergy were peanut SPT result of 8 mm or larger (odds ratio [OR] = 2.35 [95% CI 1.08-5.12]), sensitization to tree nuts (adjusted OR [aOR] = 2.51 [95% CI = 1.00-6.35]), and early-onset severe eczema (aOR = 3.23, [95% CI 1.17-8.88]). Factors at age 1 associated with persistence of egg allergy at age 6 were egg SPT result of 4 mm or larger (OR = 2.98 [95% CI 1.35-6.36]), other (peanut and/or sesame) food sensitizations (aOR = 2.80 [95% CI = 1.11-7.03]), baked egg allergy (aOR = 7.41 [95% CI = 2.16-25.3]), and early-onset severe eczema (aOR = 3.77 [95% CI = 1.35-10.52]).

CONCLUSION

Most egg allergy and nearly one-third of peanut allergy resolves naturally by age 6 years. The prevalence of peanut allergy at age 6 years was similar to that observed at age 1 year, largely owing to new-onset food peanut allergy after age 1 year. Infants with early-onset eczema, larger SPT wheals, or multiple food sensitizations and/or allergies were less likely to acquire tolerance to either peanut or egg.

Shortened Infant Telomere Length Is Associated with Attention Deficit/Hyperactivity Disorder Symptoms in Children at Age Two Years: A Birth Cohort Study

Environmental factors can accelerate telomere length (TL) attrition. Shortened TL is linked to attention deficit/hyperactivity disorder (ADHD) symptoms in school-aged children. The onset of ADHD occurs as early as preschool-age, but the TL-ADHD association in younger children is unknown. We investigated associations between infant TL and ADHD symptoms in children and assessed environmental factors as potential confounders and/or mediators of this association. Relative TL was measured by quantitative polymerase chain reaction in cord and 12-month blood in the birth cohort study, the Barwon Infant Study. Early life environmental factors collected antenatally to two years were used to measure confounding. ADHD symptoms at age two years were evaluated by the Child Behavior Checklist Attention Problems (AP) and the Attention Deficit/Hyperactivity Problems (ADHP). Associations between early life environmental factors on TL or ADHD symptoms were assessed using multivariable regression models adjusted for relevant factors. Telomere length at 12 months (TL12), but not at birth, was inversely associated with AP (β = −0.56; 95% CI (−1.13, 0.006); p = 0.05) and ADHP (β = −0.66; 95% CI (−1.11, −0.21); p = 0.004). Infant secondhand smoke exposure at one month was independently associated with shorter TL12 and also higher ADHD symptoms. Further work is needed to elucidate the mechanisms that influence TL attrition and early neurodevelopment.

Longitudinal antibody responses to peanut following probiotic and peanut oral immunotherapy (PPOIT) in children with peanut allergy

INTRODUCTION

Probiotic and Peanut Oral Immunotherapy (PPOIT) is effective at inducing sustained unresponsiveness (SU) at end-of-treatment and this effect persists up to four years post-treatment, referred to as persistent SU. We sought to evaluate (i) how PPOIT altered peanut-specific humoral immune indices, and (ii) how such longitudinal indices relate to persistent SU.

METHODS

Longitudinal serum/plasma levels of whole peanut- and peanut component- (Ara-h1, -h2, -h3, -h8, -h9) specific-IgE (sIgE) and specific-IgG4 (sIgG4) antibodies were measured by ImmunoCAP and salivary peanut-specific-IgA (sIgA) by ELISA in children (n=62) enrolled in the PPOIT-001 randomised trial from baseline (T0) to 4-years post-treatment (T5). Multivariate regression analyses of log-transformed values were used for point-in-time between group comparisons. Generalised estimating equations (GEE) were used for longitudinal comparisons between groups.

RESULTS

PPOIT was associated with changes in sIgE and sIgG4 over time. sIgE levels were significantly reduced post-treatment [T5, PPOIT v.s. Placebo ratio of geometric mean (GM): Ara-h1 0.07, p=0.008; Ara-h2 0.08, p=0.007; Ara-h3 0.15, p=0.021]. sIgG4 levels were significantly increased by end-of-treatment (T1, PPOIT v.s. Placebo ratio of GM: Ara-h1 3.77, p=0.011; Ara-h2 17.97, p<0.001; Ara-h3 10.42, p<0.001) but levels in PPOIT group decreased once treatment was stopped and returned to levels comparable with Placebo group by T5. Similarly, salivary peanut sIgA increased during treatment, as early as 4 months of treatment (PPOIT v.s. Placebo, ratio of GM: 2.04, p=0.014), then reduced post-treatment.

CONCLUSION

PPOIT was associated with broad reduction in peanut specific humoral responses which may mediate the clinical effects of SU that persists to 4-years post-treatment.

Innate Immune Activation and Circulating Inflammatory Markers in Preschool Children

Early childhood is characterised by repeated infectious exposures that result in inflammatory responses by the innate immune system. In addition, this inflammatory response to infection is thought to contribute to the epidemiological evidence linking childhood infection and adult non-communicable diseases. Consequently, the relationship between innate immune responses and inflammation during early life may inform prevention of NCDs later in life. In adults, non-genetic host factors such as age, sex, and obesity, strongly impact cytokine production and circulating mediators, but data in children are lacking. Here, we assessed cytokine responses and inflammatory markers in a population of healthy preschool children (mean age 4.2 years). We studied associations between cytokines, plasma inflammatory markers and non-genetic host factors, such as sex, age, adiposity, season, and immune cell composition. Similar to adults, boys had a higher inflammatory response than girls, with IL-12p70 and IL-10 upregulated following TLR stimulation. Adiposity and winter season were associated with increased circulating inflammatory markers but not cytokine production. The inflammatory markers GlycA and hsCRP were positively associated with production of a number of cytokines and may therefore reflect innate immune function and inflammatory potential. This dataset will be informative for future prospective studies relating immune parameters to preclinical childhood NCD phenotypes.

Children With Food Allergy Are at Risk of Lower Lung Function on High-Pollen Days

BACKGROUND

Grass pollen exposure is a risk factor for childhood asthma hospital attendances. However, its short-term influence on lung function, especially among those with other allergic conditions, has been less well-studied.

OBJECTIVE

To investigate this association in a population-based sample of children.

METHODS

Within the HealthNuts cohort, 641 children performed spirometry during the grass pollen season. Grass pollen concentration was considered on the day of testing (lag 0), up to 3 days before (lag 1-lag 3), and cumulatively (lag 0-3). We used linear regression to assess the relevant associations and examined potential interactions with current asthma, hay fever or eczema, and food allergy.

RESULTS

Associations were observed only in children with allergic disease (P value for interaction ≤ 0.1). In children with food allergy, grass pollen concentration was associated with a lower ratio of forced expiratory volume in 1 second to forced vital capacity (FEV₁/FVC) and lower mid-forced expiratory flows (FEF_25%-75%) at all lags (eg, at lag 2, FEV₁/FVC z-score = -0.50 [95% CI -0.80 to -0.20] and FEF_25%--75% z-score = -0.40 [-0.60 to -0.04] per 20 grains/m³ pollen increase), and increased bronchodilator responsiveness (BDR) at lag 2 and lag 3 (eg, at lag 2, BDR = (31 [95% CI -0.005 to 62] mL). In children with current asthma, increasing grass pollen concentration was associated with lower FEF_25%-75% and increased BDR, whereas children with current hay fever or eczema had increased BDR only.

CONCLUSIONS

A proactive approach needs to be enforced to manage susceptible children, especially those with food allergy, before high-grass pollen days.

Associations between grass pollen exposures in utero and in early life with food allergy in 12-month-old infants

Birth during pollen seasons may influence food allergy risk but no study has assessed pollen exposure. Using the HealthNuts population-based cohort of 5276 infants, we assessed grass pollen exposures, in utero and up to the first 6 months of life, on hen's egg, sesame and peanut allergy outcomes at 12 months. Cumulative pollen exposure in the first 7 days of life increased risk of peanut sensitization aMOR (adjusted multinomial odds ratio) = 1.21 (95% CI: 1.01-1.44). Exposure between first 4-6 months of life increased risk of hen's egg aMOR = 1.02 (95% CI: 1.004-1.04) and sensitization to all foods aMOR = 1.02 (95% CI: 1.003-1.04). Grass pollen exposure was associated with food challenge diagnosed food allergy, but only among infants with a maternal history of food allergy. Exposure to grass pollen in the intrauterine period and infancy may be important but more studies are needed to replicate these findings.

Associations between Body Mass Index Trajectories in the first two years of life and Allergic Rhinitis, Eczema and Food Allergy outcomes up to early adulthood

BACKGROUND

Early life body mass index (BMI) trajectories influence the risk of asthma at 18 years of age. However, it is unclear if these are also associated with other allergic diseases.

OBJECTIVES

We investigated the associations between BMI trajectories and subsequent allergic rhinitis, eczema and food sensitisation/allergies.

METHODS

Parent-reported anthropometric data were collected 18 times in the first two years of life from a cohort of 620 participants in a high-risk cohort. Group-based trajectory modelling was applied to develop BMI trajectories. Associations between trajectories and allergic rhinitis, eczema and food sensitisation at 6, 12 and 18 years of age were assessed using logistic regression models. Potential effect modifications by parental allergic disease, sex and allocated infant formula were assessed.

RESULTS

We identified five BMI trajectories: average, below average, persistently low, early low and catch up, and persistently high. None showed an association with allergic rhinitis. In participants with maternal allergic rhinitis, 'early-low and catch-up' (OR = 2.83;95%CI 1.34-5.96, P_int  = 0.05) and 'below average' trajectories (OR = 2.39; 1.18-7.23, P_int  = 0.02) were associated with allergic rhinitis at 18 years of age compared with the average trajectory. No associations were observed with eczema or food sensitisation.

CONCLUSION

Infants with early-low and catch-up, or below average BMI growth, were at increased risk of allergic rhinitis at 18 years if they had a mother with allergic rhinitis. These results require replication, but suggest that interactions between poor intrauterine growth, failure to thrive and maternal allergies may influence the risk of allergic rhinitis.

Probiotic peanut oral immunotherapy versus oral immunotherapy and placebo in children with peanut allergy in Australia (PPOIT-003): a multicentre, randomised, phase 2b trial

BACKGROUND

Oral immunotherapy is effective at inducing desensitisation to allergens and induces sustained unresponsiveness (ie, clinical remission) in a subset of patients, but causes frequent reactions. We aimed to investigate whether addition of a probiotic adjuvant improved the efficacy or safety of peanut oral immunotherapy.

METHODS

PPOIT-003, a multicentre, randomised, phase 2b trial, was conducted in three tertiary hospitals in Australia (Adelaide [SA], Melbourne [VIC], and Perth [WA]) in children aged 1-10 years, weighing more than 7 kg, with peanut allergy confirmed by a double-blind placebo-controlled food challenge (cumulative 4950 mg dose of peanut protein) and positive peanut skin prick test (≥3 mm) or peanut-specific IgE (≥0·35 kU/L). Children were randomly assigned (2:2:1) to receive probiotic and peanut oral immunotherapy (PPOIT), placebo probiotic and peanut oral immunotherapy (OIT), or placebo probiotic and placebo OIT (placebo) for 18 months, and were followed up until 12 months after completion of treatment. Oral immunotherapy consisted of increasing doses of peanut protein (commercially available food-grade 12% defatted peanut flour [50% peanut protein]) until a 2000 mg daily maintenance dose was reached. The probiotic adjuvant was a daily dose of 2 × 10¹⁰ colony-forming units of the probiotic Lactobacillus rhamnosus ATCC 53103. Placebo immunotherapy comprised maltodextrin, brown food colouring, and peanut essence, and placebo probiotic was maltodextrin. Dual primary outcomes were 8-week sustained unresponsiveness, defined as no reaction to a cumulative dose of 4950 mg peanut protein at treatment completion and 8 weeks after treatment completion, in the PPOIT versus placebo groups and the PPOIT versus OIT groups, analysed by intention to treat. Safety endpoints were adverse events during the treatment phase, and peanut ingestion and reactions in the 12-month post-treatment period. This study is registered with the Australian New Zealand Clinical Trials Registry, 12616000322437.

FINDINGS

Between July 4, 2016, and Sept 21, 2020, 201 participants were enrolled and included in the intention-to-treat analysis. 36 (46%) of 79 children in the PPOIT group and 42 (51%) of 83 children in the OIT group achieved sustained unresponsiveness compared with two (5%) of 39 children in the placebo group (risk difference 40·44% [95% CI 27·46 to 53·42] for PPOIT vs placebo, p<0·0001), with no difference between PPOIT and OIT (-5·03% [-20·40 to 10·34], p=0·52). Treatment-related adverse events were reported in 72 (91%) of 79 children in the PPOIT group, 73 (88%) of 83 children in the OIT group, and 28 (72%) of 39 children in the placebo group. Exposure-adjusted incidence of adverse events was 10·58 in the PPOIT group, 11·36 in the OIT, and 2·09 in the placebo group (ratio 0·92 [95% CI 0·85 to 0·99] for PPOIT vs OIT, p=0·042; 4·98 [4·11-6·03] for PPOIT vs placebo, p<0·0001; 5·42 [4·48-6·56] for OIT vs placebo, p<0·0001), with differences seen primarily in gastrointestinal symptoms and in children aged 1-5 years. During the 12-month post-treatment period, 60 (85%) of 71 participants in the PPOIT group, 60 (86%) of 70 participants in the OIT group, and six (18%) of 34 participants in the placebo group were eating peanut; rescue epinephrine use was infrequent (two [3%] of 71 in the PPOIT group, four [6%] of 70 in the OIT group, and none in the placebo group).

INTERPRETATION

Both PPOIT and OIT were effective at inducing sustained unresponsiveness. Addition of a probiotic did not improve efficacy of OIT, but might offer a safety benefit compared with OIT alone, particularly in preschool children.

FUNDING

National Health and Medical Research Council Australia and Prota Therapeutics.