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

A pathway-based genetic score for inflammation: An indicator of vulnerability to phthalate-induced adverse neurodevelopment outcomes

INTRODUCTION

Phthalates, chemical additives used to enhance plastic products' flexibility, are easily released into the environment, and can harm the brain development through various mechanisms including inflammation. Genetic variation influencing an individual's susceptibility to inflammation may play a role in the effects of phthalate exposure on neurodevelopment however there is no summary measure developed for genetic susceptibility to inflammation.

METHODS

We developed a genetic pathway function score for inflammation (gPFSin), based on the transcriptional activity of the inflammatory response pathway in the brain and other tissues. Using the Barwon Infant Study (a birth cohort of n = 1074), we examined the connection between gPFSin and key neurodevelopmental outcomes, along with the interplay between prenatal phthalate levels, children's genetic susceptibility to inflammation (gPFSin), and adverse neurodevelopmental outcomes.

RESULTS

Regression techniques revealed consistent associations between gPFSin-phthalate combinations and key neurodevelopmental outcomes. A high gPFSin score was associated with an increased risk of doctor-diagnosed Autism Spectrum Disorder (ASD) and Attention-Deficit/Hyperactivity Disorder (ADHD) by age 11.5 years, with adjusted odds ratios of 2.15(p = 0.039) and 2.42(p = 0.005), respectively. Furthermore, individuals with both high gPFSin and prenatal phthalate exposure exhibited more neurodevelopmental problems. This included associations of high gPFSin and bis(2-ethylhexyl) phthalate (DEHP) levels with parent-reported ASD traits and doctor-diagnosed ASD. The attributable proportions due to this interaction were 0.39 (p = 0.045) and 0.37 (p = 0.037), respectively.

CONCLUSION

These findings contribute to the evidence linking gestational phthalate exposure and inflammation to adverse neurodevelopment and underscoring increased risks in children with higher genetic susceptibility to inflammation.

Regulatory T-Cells During Pregnancy Relate to Women's Own Childhood History of Microbial Exposure

OBJECTIVES

Previous studies found that children with siblings, farm residence, and other proxies of greater microbial contacts had lower rates of hyper-responsive immune disorders. Yet, scientific debate persists regarding whether the human immune system is educated in early life primarily as a function of pathogenic or benign microbial exposures, or both. Furthermore, pregnancy relies on women's intrinsic immunosuppressive function, yet it remained unknown how immunoregulation in pregnant women relates to early-life microbial exposures. Here, we conduct a preliminary examination of whether childhood microbial exposures prime women's pregnancy-related immunoregulatory capacity.

METHODS

We administered retrospective questionnaires to estimate 55 pregnant women's early-life exposure to pathogenic (e.g., illness) and benign (e.g., pets; rural residence) microbes. Tolerogenic regulatory T-cells (Tregs) and Treg subtypes were measured by flow cytometry from peripheral blood.

RESULTS

Results show that proxies for both pathogenic and benign exposures were positively associated with Treg concentrations.

CONCLUSIONS

These findings offer insights that may help elucidate the relative contributions of early-life pathogenic ("hygiene hypothesis") and benign ("old friends hypothesis") microbial exposures toward the expansion of the Treg compartment. Human evolutionary history is characterized by changing microbial exposures as human residency patterns, living environments, and subsistence strategies changed. In this context, our findings suggest the possibility of less gestational pathology in human evolutionary past conditions typified by richer diversity of microbial exposure.

A unique human cord blood CD8+CD45RA+CD27+CD161+ T-cell subset identified by flow cytometric data analysis using Seurat

Advances in single-cell level analytical techniques, especially cytometric approaches, have led to profound innovation in biomedical research, particularly in the field of clinical immunology. This has resulted in an expansion of high-dimensional data, posing great challenges for comprehensive and unbiased analysis. Conventional manual analysis is thus becoming untenable to handle these challenges. Furthermore, most newly developed computational methods lack flexibility and interoperability, hampering their accessibility and usability. Here, we adapted Seurat, an R package originally developed for single-cell RNA sequencing (scRNA-seq) analysis, for high-dimensional flow cytometric data analysis. Based on a 20-marker antibody panel and analyses of T-cell profiles in both adult blood and cord blood (CB), we showcased the robust capacity of Seurat in flow cytometric data analysis, which was further validated by Spectre, another high-dimensional cytometric data analysis package, and conventional manual analysis. Importantly, we identified a unique CD8+ T-cell population defined as CD8+CD45RA+CD27+CD161+ T cell that was predominantly present in CB. We characterised its IFN-γ-producing and potential cytotoxic properties using flow cytometry experiments and scRNA-seq analysis from a published dataset. Collectively, we identified a unique human CB CD8+CD45RA+CD27+CD161+ T-cell subset and demonstrated that Seurat, a widely used package for scRNA-seq analysis, possesses great potential to be repurposed for cytometric data analysis. This facilitates an unbiased and thorough interpretation of complicated high-dimensional data using a single analytical pipeline and opens a novel avenue for data-driven investigation in clinical immunology.

Low vitamin D during pregnancy is associated with infantile eczema by up-regulation of PI3K/AKT/mTOR signaling pathway and affecting FOXP3 expression: A bidirectional cohort study

Vitamin D has received increasing attention because of its association with atopic disease development. Limited studies that have been done on the impact of maternal vitamin D levels during pregnancy on infantile eczema are still debatable. We wanted to discover the effect of maternal vitamin D on infantile eczema and explore whether regulatory T cells (Treg) play a role in this process. 219 pairs of mothers and children were enrolled. Maternal fasting venous blood was collected in pregnancy's second and third trimesters to determine vitamin D levels. Cord blood and placenta samples were collected during childbirth for detecting levels of genes, proteins and cytokines. Pediatricians followed up the prevalence of eczema in infants within 1 year. The reported rate of vitamin D deficiency and insufficiency was 35.6% and 28.3%. Lower maternal 25(OH)D3 levels were related to a higher risk of infantile eczema. Foxp3 gene expression is lower in cord blood of infants with eczema compared to infants without eczema. There was a positive correlation between maternal 25(OH)D3 levels and the expression of FOXP3 gene in cord blood. Compared to vitamin D sufficiency women, vitamin D deficiency women's placental FOXP3 protein expression was decreased and PI3K/AKT/mTOR protein was up-regulated. Our study demonstrates that low prenatal maternal vitamin D levels increased the risk of infantile eczema aged 0-1 year, which might be related to the downregulating of the FOXP3 gene expression in cord blood and decreased placental FOXP3 protein expression. Low placental FOXP3 protein was related with activating PI3K/AKT/mTOR signaling pathway.

Food Allergen Immunotherapy in the Treatment of Patients with IgE-Mediated Food Allergy

The prevalence of allergic diseases, including food allergy, is increasing, especially in developed countries. Implementation of an elimination diet is not a sufficient therapeutic strategy in patients with food allergy, whose quality of life is significantly impaired. In recent years, new effective therapeutic strategies have been developed, such as the application of oral, sublingual, and epicutaneous immunotherapy. Oral immunotherapy is the most often applied strategy because of its effectiveness and ease of application, with an acceptable safety profile. The effectiveness of oral immunotherapy in patients with egg, cow's milk, and peanut allergy has been proven both in terms of raising of the threshold and the development of tolerance, and in some patients, the development of sustainable unresponsiveness. Although oral immunotherapy is an effective treatment for food allergy, several limitations, including a long duration and a significant rate of reported adverse events, reduces its success. Therefore, new therapeutic options, such as treatment with biologicals, either as combinations with food allergen immunotherapy or as monotherapy with the aim of improving the efficacy and safety of treatment, are being investigated.

Associations between home environmental factors and childhood eczema and related symptoms in different cities in China

Previous studies have shown significant associations between home environmental factors and childhood eczema. However, few studies have compared how associations differ in different regions. This study investigated associations between home environmental factors and childhood eczema ever, and related symptoms including itchy rash (IR) and being awakened by itchy rash at night (awake by IR) in 4 cities located in different regions of China, based on cross-sectional investigations during 2010-2012. We used two-step analysis to explore the associations between influencing factors and eczema/related symptoms: first, group Least Absolute Shrinkage and Selection Operator (LASSO) was conducted to identify important factors among a list of candidates; then, the associations in total study population and in each city were estimated using logistic regression. We found these home environmental factors to be risk factors for eczema or related symptoms: large residence size, shared room, air cleaner at home, abnormal smell, perceived dry air, visible mold or damp stains, cooking with coal or wood, painted wall, incense, mice, new furniture during pregnancy, abnormal smell at birth, window condensation at birth and environmental tobacco smoke at birth. Environmental protective factors were rural house location and window ventilation. Associations of factors with eczema/related symptoms differed across cities. For example, air conditioning was protective for eczema in Beijing and awakening by IR in Shanghai with ORs of 0.70 (95%CI: 0.52, 0.95) and 0.33 (95%CI: 0.14, 0.81) respectively, but not significant in other cities. Our results have implications for improving home environments to reduce the risk of childhood eczema/related symptoms in different regions of China.

Gut microbiome immaturity and childhood acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is the most common cancer of childhood. Here, we map emerging evidence suggesting that children with ALL at the time of diagnosis may have a delayed maturation of the gut microbiome compared with healthy children. This finding may be associated with early-life epidemiological factors previously identified as risk indicators for childhood ALL, including caesarean section birth, diminished breast feeding and paucity of social contacts. The consistently observed deficiency in short-chain fatty-acid-producing bacterial taxa in children with ALL has the potential to promote dysregulated immune responses and to, ultimately, increase the risk of transformation of preleukaemic clones in response to common infectious triggers. These data endorse the concept that a microbiome deficit in early life may contribute to the development of the major subtypes of childhood ALL and encourage the notion of risk-reducing microbiome-targeted intervention in the future.

Peanut allergy: risk factors, immune mechanisms, and best practices for oral immunotherapy success

INTRODUCTION

Peanut oral immunotherapy (pOIT) is the only FDA-approved treatment for food allergy and its adoption amongst allergist immunologists and their patients is growing. pOIT is the subject of numerous clinical trials, however, the focus is often on treatment efficacy, safety, and tolerability, rather than identifying patients most likely to benefit from pOIT. Here, we review existing data on the clinical and immunological outcomes of pOIT that inform best practices for pOIT candidate selection.

AREAS COVERED

In this review, we describe the natural history of peanut allergy, summarize immunological and clinical outcomes of pOIT at different ages, discuss the optimization of pOIT in key age groups, and finally suggest an ideal age range at which to initiate pOIT for best outcomes.

EXPERT OPINION

pOIT is currently underutilized by patients and allergist-immunologists. Developing guidelines for selecting appropriate patients and optimizing treatment may help to increase access to pOIT. Many aspects of pOIT need additional study to further our understanding of the optimal timing to start pOIT, with careful consideration to clinical, immunological, and quality of life outcomes.