Genetics and epigenetics of allergy

Multifaceted roles of trained immunity in diverse pathological contexts

Trained immunity, an innate immune response characterized by enhanced cellular responsiveness, exhibits a profound memory akin to adaptive immunity. This phenomenon involves intricate metabolic and epigenetic reprogramming triggered by stimuli such as β-glucan and BCG, shaping innate immune memory. Following elucidation of the background on trained immunity, it is important to explore its multifaceted roles in various pathological contexts. In this review, we delve into the specific contributions of trained immunity in the intricate landscape of viral infections, tumorigenesis, and diverse inflammatory diseases, shedding light on its potential as a therapeutic target, and offering comprehensive understanding of its broader immunological implications. [BMB Reports 2024; 57(10): 431-440].

Evaluation of Childhood Allergy Risk Among Pregnant Women in a Tertiary Care Hospital in Thailand

OBJECTIVES

This study aims to evaluate the prevalence of pregnant women whose children are at higher risk for childhood allergies and to assess knowledge of risk assessment and prevention strategies.

METHODS

A cross-sectional study was conducted on 310 pregnant women in an antenatal care clinic at a tertiary care hospital in Thailand. In addition to baseline demographic and obstetric characteristics, all participating pregnant women were asked to complete a questionnaire regarding risk evaluation and knowledge of childhood allergies on various topics. A childhood allergy risk assessment was evaluated based on the history of allergy disease in immediate family members. The questionnaire on knowledge was derived from a guideline issued by the Allergy, Asthma, and Immunology Association of Thailand, with possible scores of 0-30.

RESULTS

The mean maternal age was 30.6 years, and 139 (44.8%) were nulliparous. Overall, 86 couples (27.7%) were at high risk for childhood allergies. The mean total knowledge score was 15.2 out of 30, and only 24 women (7.7%) had an overall score of >20, and 40 women (12.9%) had an overall score of ≤10. The mean knowledge score for almost every subtopic was less than half of the possible points, except for the risk reduction strategies during pregnancy. Comparisons between those with higher and lower scores (≥16 vs. ≤15 points) showed that women with higher knowledge scores were significantly more likely to have had a previous child with an allergy (p=0.010).

CONCLUSION

The prevalence of pregnant women whose children were at higher risk for childhood allergies was 27.7% (86 of 310 couples). The women had limited knowledge of childhood allergies with regard to risk assessment, risk reduction strategies, and various interventions. The only factor associated with a higher knowledge score was having a previous child with an allergy.

From trained immunity in allergy to trained immunity-based allergen vaccines

Innate immune cells experience long lasting metabolic and epigenetic changes after an encounter with specific stimuli. This facilitates enhanced immune responses upon secondary exposition to both the same and unrelated pathogens, a process termed trained immunity. Trained immunity-based vaccines (TIbV) are vaccines able to induce innate immune memory, thus conferring heterologous protection against a broad range of pathogens. While trained immunity has been well documented in the context of infections and multiple immune-mediated diseases, the role of innate immune memory and its contribution to the initiation and maintenance of chronic allergic diseases remains poorly understood. Over the last years, different studies attempting to uncover the role of trained immunity in allergy have emerged. Exposition to environmental factors impacting allergy development such as allergens or viruses induces the reprogramming of innate immune cells to acquire a more pro-inflammatory phenotype in the context of asthma or food allergy. Several studies have convincingly demonstrated that prevention of viral infections using TIbV contributes to reduce wheezing attacks in children, which represent a high-risk factor for asthma development later in life. Innate immune cells trained with specific stimuli might also acquire anti-inflammatory features and promote tolerance, which may have important implications for chronic inflammatory diseases such as allergies. Recent findings showed that allergoid-mannan conjugates, which are next generation vaccines for allergen-specific immunotherapy (AIT), are able to reprogram monocytes into tolerogenic dendritic cells by mechanisms depending on metabolic and epigenetic rewiring. A better understanding of the underlying mechanisms of trained immunity in allergy will pave the way for the design of novel trained immunity-based allergen vaccines as potential alternative strategies for the prevention and treatment of allergic diseases.

A pathogenic integrated view explaining the different endotypes of asthma and allergic disorders

The inflammation of allergic diseases is characterized by a complex interaction between type 2 and type 3 immune responses, explaining clinical symptoms and histopathological patterns. Airborne stimuli activate the mucosal epithelium to release a number of molecules impacting the activity of resident immune and environmental cells. Signals from the mucosal barrier, regulatory cells, and the inflamed tissue are crucial conditions able to modify innate and adaptive effector cells providing the selective homing of eosinophils or neutrophils. The high plasticity of resident T- and innate lymphoid cells responding to external signals is the prerequisite to explain the multiplicity of endotypes of allergic diseases. This notion paved the way for the huge use of specific biologic drugs interfering with pathogenic mechanisms of inflammation. Based on the response of the epithelial barrier, the activity of resident regulatory cells, and functions of structural non-lymphoid environmental cells, this review proposes some immunopathogenic scenarios characterizing the principal endotypes which can be associated with a precise phenotype of asthma. Recent literature indicates that similar concepts can also be applied to the inflammation of other non-respiratory allergic disorders. The next challenges will consist in defining specific biomarker(s) of each endotype allowing for a quick diagnosis and the most effective personalized therapy.

Omics technologies in allergy and asthma research: An EAACI position paper

Allergic diseases and asthma are heterogenous chronic inflammatory conditions with several distinct complex endotypes. Both environmental and genetic factors can influence the development and progression of allergy. Complex pathogenetic pathways observed in allergic disorders present a challenge in patient management and successful targeted treatment strategies. The increasing availability of high-throughput omics technologies, such as genomics, epigenomics, transcriptomics, proteomics, and metabolomics allows studying biochemical systems and pathophysiological processes underlying allergic responses. Additionally, omics techniques present clinical applicability by functional identification and validation of biomarkers. Therefore, finding molecules or patterns characteristic for distinct immune-inflammatory endotypes, can subsequently influence its development, progression, and treatment. There is a great potential to further increase the effectiveness of single omics approaches by integrating them with other omics, and nonomics data. Systems biology aims to simultaneously and longitudinally understand multiple layers of a complex and multifactorial disease, such as allergy, or asthma by integrating several, separated data sets and generating a complete molecular profile of the condition. With the use of sophisticated biostatistics and machine learning techniques, these approaches provide in-depth insight into individual biological systems and will allow efficient and customized healthcare approaches, called precision medicine. In this EAACI Position Paper, the Task Force "Omics technologies in allergic research" broadly reviewed current advances and applicability of omics techniques in allergic diseases and asthma research, with a focus on methodology and data analysis, aiming to provide researchers (basic and clinical) with a desk reference in the field. The potential of omics strategies in understanding disease pathophysiology and key tools to reach unmet needs in allergy precision medicine, such as successful patients' stratification, accurate disease prognosis, and prediction of treatment efficacy and successful prevention measures are highlighted.

Association between EPHA5 methylation status in peripheral blood leukocytes and the risk and prognosis of gastric cancer

Purpose

Altered DNA methylation, genetic alterations, and environmental factors are involved in tumorigenesis. As a tumor suppressor gene, abnormal EPHA5 methylation was found in gastric cancer (GC) tissues and was linked to the initiation, progression and prognosis of GC. In this study, the EPHA5 methylation level in peripheral blood leukocytes (PBLs) was detected to explore its relationship with GC risk and prognosis.

Methods

A total of 366 GC cases and 374 controls were selected as the subjects of this study to collect their environmental factors, and the EPHA5 methylation status was detected through the methylation-sensitive high-resolution melting method. Logistic regression analysis was utilized to evaluate the associations among EPHA5 methylation, environmental factors and GC risk. Meanwhile, the propensity score (PS) was used to adjust the imbalance of some independent variables.

Results

After PS adjustment, EPHA5 Pm (positive methylation) was more likely to increase the GC risk than EPHA5 Nm (negative methylation) (OR^b = 1.827, 95% CI [1.202-2.777], P = 0.005). EPHA5 Pm had a more significant association with GC risk in the elderly (OR^a = 2.785, 95% CI [1.563-4.961], P = 0.001) and H. pylori-negative groups (OR^a = 2.758, 95% CI [1.369-5.555], P = 0.005). Moreover, the combined effects of EPHA5 Pm and H. pylori infection (OR_c ^a = 3.543, 95% CI [2.233-5.621], P < 0.001), consumption of alcohol (OR_c ^a = 2.893, 95% CI [1.844-4.539], P < 0.001), and salty food intake (OR_c ^a = 4.018, 95% CI [2.538-6.362], P < 0.001) on increasing the GC risk were observed. In addition, no convincing association was found between EPHA5 Pm and the GC prognosis.

Conclusions

EPHA5 methylation in PBLs and its combined effects with environmental risk factors are related to the GC risk.

The multifaceted aspects of ocular allergies: Phenotypes and endotypes

Like the lung, skin, and nose, the external eye is a common target of allergic inflammation. Ocular allergy (OA) represents a collection of underestimated diseases of the eye observed in children and adults. The ocular manifestations are the expression of multifactorial immune mechanisms that generally have a good prognosis, but for a few patients, long term inflammation may remarkably reduce the visual function. Evidence suggests that other co-participant systems, including epigenetic, genetic, environmental, individual factors, sex hormones, and the central and autonomic nervous systems may influence the ocular response from distant sites. This is consistent with the concept that the eye is an organ fully integrated with the rest of the body and that the therapeutic approach should be holistic, dynamic, and personalized. For instance, androgens and estrogens binding to receptors on the ocular surface and the continuous cross-talking of neuromediators and growth factors with immune cells act to maintain the ocular surface homeostasis in response to environmental challenges. The immune system links and regulates the response of the ocular surface. Complex and incompletely understood mechanisms influence the innate and adaptive immune responses and generate different OA phenotypes and endotypes discussed in the present review.

Follistatin-related protein 1 in asthma: miR-200b-3p interactions affect airway remodeling and inflammation phenotype

Follistatin-related protein 1 (FSTL1) is significantly associated with the asthma severity and outcome in humans and diverse mouse models of asthma. Previous studies have also suggested that FSTL1 could activate autophagy and NLRP3, thus playing as a causative agent in the asthma progression. However, mechanisms that regulate airway epithelial cell-specific FSTL1 expression and function in asthma are unknown. Here, we further evaluated the spatiotemporal relationships between the FSTL1 and asthma development through ovalbumin (OVA) -induced asthma models. Integrative analysis in asthmatics airway epithelium identifies microRNA (miR)-200b-3p as a novel upstream of FSTL1. Next, we collected airway biopsies, induced sputum, and blood samples isolated from asthmatics patients and the OVA-induced mouse model. We revealed that miR-200b-3p expression is downregulated in asthmatics airway epithelium, while its expression was negatively correlated with FSTL1. On this basis, the function and expression pattern analysis of miR-200b-3p were performed using miRNA-target prediction databases and long non-coding RNA (lncRNA) microarray assay. It is illustrated that miR-200b-3p, which is downregulated with pro-fibrotic stimulation of TGF-β1, could also be sponged by lncRNA PCAT19 and regulate FSTL1 expression in asthma progression. In vivo, miR-200b-3p overexpression in mice prevents OVA-induced airway remodeling and inflammation. Lastly, protective roles of miR-200b-3p are partly attributed to the direct and functional repression of FSTL1. Our findings suggest a crucial role for the miR-200b-3p/FSTL1 axis in regulating asthmatic's airway remodeling and inflammation phenotype.