The increase in the prevalence of allergic diseases is believed to partially depend on environmental changes. DNA methylation is a major epigenetic mechanism, which is known to respond to environmental factors. A number of studies have revealed that patterns of DNA methylation may potentially predict allergic diseases. Here, we examined how maternal atopy is associated with methylation patterns in the cord blood of neonates. We conducted an epigenome-wide association study in a cohort of 96 mother-child pairs. Pregnant women aged not more than 35 years old, not currently smoking or exposed to environmental tobacco smoke, who did not report obesity before conception were considered eligible. They were further tested for atopy. Converted DNA from cord blood was analysed using Infinium MethylationEPIC; for statistical analysis, RnBeads software was applied. Gestational age and sex were included as covariates in the final analysis. 83 DM sites were associated with maternal atopy. Within the top DM sites, there were CpG sites which mapped to genes SCD, ITM2C, NT5C3A and NPEPL1. Regional analysis revealed 25 tiling regions, 4 genes, 3 CpG islands and 5 gene promoters, (including PIGCP1, ADAM3A, ZSCAN12P1) associated with maternal atopy. Gene content analysis revealed pointwise enrichments in pathways related to purine-containing compound metabolism, the G1/S transition of the mitotic cell cycle, stem cell division and cellular glucose homoeostasis. These findings suggest that maternal atopy provides a unique intrauterine environment that may constitute the first environment in which exposure is associated with methylation patterns in newborn.

Interleukin 4 (IL-4) and its receptor play important roles in the pathologies of asthma and atopy. The alpha subunit of the IL-4 receptor (IL-4RA) is included in 2 types of receptors which have different modulatory effects on immune responses. This distinct pattern reflects involvement in the immunopathology of both asthma and atopy. A number of studies have proven the association between IL4RA gene polymorphisms and asthma and atopy, but it is still an open question whether these variants are functional. To analyze the data from IL4RA gene expression in PBMC in relation to specific polymorphisms - the most frequently studied I50V and Q551R and the less known C-3223T. The analysis was performed for 36 subjects, both atopic and non-atopic. Real-time polymerase chain reaction (PCR) was used with specific primers for the quantification and genotyping. Delta Ct (ΔCT) and delta-delta Ct (ΔΔCT) values were used for the relative quantification of IL4RA expression in PBMC. We observed no significant differences in the IL4RA expression profile between the 3 genotypes. A trend toward higher relative expression was observed for homozygous minor I50V and C-3223T genotypes. We did not find a statistically significant relationship between the genetic polymorphisms and the relative expression of IL4RA. The effect of genetic polymorphism on IL4RA mRNA expression could interfere with other factors, such as environmental stimuli, and should be evaluated in future studies.

As the burden of mild asthma is not well understood, the significance of expanding research in the group of patients with mild asthma is emphasized. Thymic stromal lymphopoietin (TSLP) and interleukin 33 (IL-33) are involved in the pathogenesis of atopy and the immune response to inhaled environmental insults, such as allergens, in asthmatic patients. Objectives: The objective of this study was to explore the correlation between specific polymorphisms within the genes encoding TSLP and IL-33, as well as the concentrations of TSLP and IL-33 in the serum, and the occurrence of pediatric mild asthma. Methods: The analysis encompassed 52 pediatric patients diagnosed with mild bronchial asthma, including both atopic and non-atopic cases, and a control group of 26 non-asthmatic children. Recruitment was conducted through a comprehensive questionnaire. Parameters such as allergic sensitization, serum levels of circulating TSLP and IL-33, and the identification of single-nucleotide polymorphisms in TSLP (rs11466750 and rs2289277) and IL-33 (rs992969 and rs1888909) were assessed for all participants. Results: Significantly lower mean serum TSLP concentrations were observed in asthmatic subjects compared to the control group, with atopic asthma patients showing even lower TSLP levels than non-atopic counterparts. No significant differences were found in mean serum IL-33 concentrations between the two groups. Considering the allele model, for both tested SNPs of IL-33, we observed that patients with asthma, atopic asthma, and atopy statistically less frequently possess the risk allele. Conclusions: Our study findings suggest that IL-33 and TSLP do not serve as ideal biomarkers for mild asthma in children. Their effectiveness as biomarkers might be more relevant for assessing disease severity rather than identifying asthma in pediatric patients. Further research focusing on the association between TSLP and IL-33 gene polymorphisms and asthma is expected to significantly advance disease management.

Allergic diseases commonly coexist, manifesting in a sequence described as the “allergic march”. Background/Objectives: This study aimed to evaluate TSLP’s and IL-1β’s potential as biomarkers in both single and multi-pediatric atopic diseases like atopic eczema, food allergy, and anaphylaxis and analyze specific SNPs in the TSLP and IL-1β genes to determine their associations with their occurrence and severity. Methods: This analysis included 109 atopic children diagnosed with atopic dermatitis, food allergy, or anaphylaxis alongside a control group of 57 non-atopic children. Recruitment was facilitated through the use of a comprehensive questionnaire. For the study population, the allergen profile was characterized at the molecular level by measuring specific IgE to purified natural or recombinant allergens, assessing serum levels of circulating TSLP and IL-1β, and identifying single-nucleotide polymorphisms in TSLP (rs2289277) and IL-1β (rs16944 C-511T). Results: The serum levels of TSLP and IL-1β were elevated in the study groups compared to the control group, highlighting their significance in the pathogenesis of the studied diseases. Carrying a higher number of the risk allele [C] in the TSLP SNP rs2289277 is associated with the greatest likelihood of having multiple concurrent allergic conditions, with the highest risk observed in individuals with all three conditions—atopic dermatitis, food allergy, and anaphylaxis, simultaneously. Moreover, children carrying the risk allele had a twofold increased risk of polysensitization, which rose to sixfold in those with two copies of the risk allele. Although no significant variations in genotype frequencies were detected for IL-1β rs16944, significant associations were observed for TSLP rs2289277, particularly with conditions such as atopic dermatitis, food allergy, anaphylaxis, and combinations of these diseases. Conclusions: Further research is required to elucidate these pathways and their role in the development of allergic diseases.

IL-4 and IL-4RA are key factors in allergic inflammation. IL-4 stimulates both IgE production and Th2 lymphocyte differentiation. Increased levels of IL-4 and IL-4RA have been shown in allergic patients. Genetic analyses have confirmed that polymorphisms within the IL-4RA gene influence the risk of allergy and can change the expression of the protein. Due to gene-environment interactions, this process is also likely to be modified by environmental exposure. The aim of the study was to evaluate the IL-4RA gene expression in peripheral blood mononuclear cells (PBMC) from atopic and non-atopic subjects with regard to place of living (urban vs rural). We enrolled 38 subjects into the study, 18 of whom were atopic. Atopy was estimated according to the results of a skin prick test. PBMC were isolated from whole blood, total RNA was extracted and reverse transcribed into cDNA. We performed real-time PCR to measure gene expression, the ACTB gene was chosen as a reference and the delta-delta Ct (ΔΔCT) method was applied for relative quantification. The Mann-Whitney U test was used for statistics. We did not observe any statistically significant differences in the gene expression profile between atopic and non-atopic subjects regardless of their place of living. However, a trend was observed for atopic rural inhabitants to have lower levels of IL-4RA gene expression than atopic subjects living in the town. The regulation of IL-4RA gene expression is complex and probably influenced by both genetic and environmental factors, such as farming exposures, which could provide the counterbalance to atopy.

Atopic eczema and asthma frequently co-occur, forming a distinct complex phenotype that likely arises from shared genetic pathways and early-life environmental influences. We aimed to investigate whether variants in TNS1 and NRXN1—previously identified in a genome-wide interaction study—influence susceptibility to atopic eczema and the asthma–eczema phenotype and whether early-life environmental tobacco smoke (ETS) exposure modifies these genetic effects. A total of 188 Caucasian children under 2 years at recruitment were prospectively followed up to 6 years of age. Eligibility of all participants for the study or control group was based on a questionnaire and a physician-confirmed diagnosis of eczema and asthma. Early-life ETS exposure was assessed by parental questionnaire. All participants were genotyped for TNS1 and NRXN1 SNPs. The TNS1 rs918949 [T] allele was associated with the combined asthma–eczema phenotype but not with eczema alone. Synergistic gene–environment interactions were identified for both TNS1 and NRXN1, with the highest risk of the combined asthma–eczema phenotype observed among ETS-exposed carriers of risk alleles. Our findings provide the first independent replication of evidence suggesting that TNS1 and NRXN1 may contribute to the asthma–eczema comorbidity through mechanisms that could be substantially modified by early-life ETS exposure.