Association of TLR4 polymorphisms with symptomatic respiratory syncytial virus infection in high-risk infants and young children

Respiratory syncytial virus (RSV) is a leading cause of infant mortality worldwide. Although anti-RSV Ab prophylaxis has greatly reduced infant mortality in the United States, there is currently no vaccine or effective antiviral therapy. RSV fusion (F) protein activates cells through TLR4. Two single nucleotide polymorphisms (SNPs) encoding Asp299Gly and Thr399Ile substitutions in the TLR4 ectodomain were previously associated with TLR4 hyporesponsiveness and increased susceptibility to bacterial infection. Prevalence of these SNPs was analyzed in a case series of 105 DNA samples extracted from archived nasal lavage samples from high-risk infants/young children with confirmed RSV disease who participated in two seminal clinical trials for anti-RSV prophylaxis. Frequencies of TLR4 SNPs in the case series were compared with those of literature controls, healthy adults, infants, and young children who presented with symptoms of respiratory infections (but not preselected for high risk for RSV). Both SNPs were highly associated with symptomatic RSV disease in this largely premature population (p < 0.0001), with 89.5% and 87.6% of cases being heterozygous for Asp299Gly and Thr399Ile polymorphisms versus published control frequencies of 10.5% and 6.5%, respectively. The other two control groups had similarly low frequencies. Our data suggest that heterozygosity of these two extracellular TLR4 polymorphisms is highly associated with symptomatic RSV disease in high-risk infants and support a dual role for TLR4 SNPs in prematurity and increased susceptibility to RSV not revealed by analysis of either alone.     

A preliminary study of gut dysbiosis in children with food allergy

Gut microbiota of food allergic children was analyzed by high throughput 16S rRNA gene sequencing. Signs of gut dysbiosis, which is likely associated with gut inflammation, was observed in children with food allergies. For example, decreased abundance of genus Akkermansia but increased abundance of Veillonella was found in children with food allergy in comparison with healthy control children.     

TLR3 and TLR4 expression in healthy and diseased human endometrium

Background  

Toll-like receptors (TLRs) play an essential role in the innate immune system by initiating and directing immune response to pathogens. TLRs are expressed in the human endometrium and their regulation might be crucial for the pathogenesis of endometrial diseases.     

The evaluation of food allergy on behavior in autistic children

Background:

Despite many efforts, the etiology of autism remains unknown. Food allergy has been suggested as a pathogenic factor in Autism Spectrum Disorder (ASD). Our aim in this study was to determine whether food allergy could be considered as a risk factor for autistic children.

Methods:

Thirty-nine autistic children were examined by the skin prick test (SPT), and total serum IgE was evaluated by ELISA. SPTs were performed for egg whites, oranges, peanuts, tomatoes, tuna fish, walnuts, aubergines, melons, grapes, and cow milk. Parents and teachers were then asked to exclude these items from the childrens’ diets for six months. After the treatment period, the autistic children who tested positive for food allergies were re-assessed by a standard questionnaire to obtain further information about their medical histories.

Results:

Three of the study’s 39 autistic children (7.7%) tested positive on the SPT. Total serum IgE levels were elevated in 56.4% of the subjects (mean=164±24.5, cut-off >155 IU/ml). The results showed a decreased mean in the childrens’ autistic behaviors on the Children Autism Rating Scale (CARS) after both eight weeks and six months; however, this decrease was not statistically significant.

Conclusion:

Food allergy may play a role in the pathophysiology of autism. We conclude that avoidance of certain foods benefits the behavior of autistic children.Key Words: Autism, Food allergy, Skin prick test     

Increased hepatic expression of TLR2 and TLR4 in the hepatic inflammation-fibrosis-carcinoma sequence

We evaluated expression of TLR2, TLR4 and proinflammatory genes [NF-κB, TNF-α, cyclooxygenase-2 (COX-2)] in liver samples of patients in different stages of liver disease. Fifteen patients with unexplained transaminases elevation (reference group), 22 with viral chronic hepatitis (hepatitis group), 14 with virus-induced severe fibrosis/cirrhosis (cirrhosis group) and 10 with hepatocarcinoma (hepatocarcinoma group) were consecutively included in the study. Quantification of TLR2, TLR4, NF-κB, TNF-α and COX-2 mRNA was done by real-time RT-PCR and TLR2 and TLR4 protein expression was evaluated by immunohistochemistry. Compared with reference, TLR2 and TLR4 mRNA was increased in hepatitis (TLR2: 2.66?±?0.69; TLR4: 3.11?±?0.79; P?相似文献   

Regional mucosa-associated microbiota determine physiological expression of TLR2 and TLR4 in murine colon

Many colonic mucosal genes that are highly regulated by microbial signals are differentially expressed along the rostral-caudal axis. This would suggest that differences in regional microbiota exist, particularly mucosa-associated microbes that are less likely to be transient. We therefore explored this possibility by examining the bacterial populations associated with the normal proximal and distal colonic mucosa in context of host Toll-like receptors (TLR) expression in C57BL/6J mice housed in specific pathogen-free (SPF) and germ-free (GF) environments. 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and clone library analysis revealed significant differences in the community structure and diversity of the mucosa-associated microbiota located in the distal colon compared to proximal colon and stool, the latter two clustering closely. Differential expression of colonic TLR2 and TLR4 along the proximal-distal axis was also found in SPF mice, but not in GF mice, suggesting that enteric microbes are essential in maintaining the regional expression of these TLRs. TLR2 is more highly expressed in proximal colon and decreases in a gradient to distal while TLR4 expression is highest in distal colon and a gradient of decreased expression to proximal colon is observed. After transfaunation in GF mice, both regional colonization of mucosa-associated microbes and expression of TLRs in the mouse colon were reestablished. In addition, exposure of the distal colon to cecal (proximal) microbiota induced TLR2 expression. These results demonstrate that regional colonic mucosa-associated microbiota determine the region-specific expression of TLR2 and TLR4. Conversely, region-specific host assembly rules are essential in determining the structure and function of mucosa-associated microbial populations. We believe this type of host-microbial mutualism is pivotal to the maintenance of intestinal and immune homeostasis.     

儿童肠道菌群与食物过敏关系的研究进展

食物过敏(food allergy, FA)在儿童中的发生率逐年升高,严重影响其生活质量,已经成为全球面临的公共卫生问题之一。近年来,人们发现FA儿童的肠道菌群组成与健康儿童有显著差异。深入研究发现,肠道菌群可通过调节树突状细胞、辅助性T细胞、调节性T细胞、肥大细胞和粒细胞等免疫细胞维持免疫平衡,也可通过多种方式增强肠道屏障功能,抑制FA的发生。在已有研究基础上,益生菌和益生元在治疗儿童FA方面也得到了一定应用,但目前的应用效果并不明确。本文以婴幼儿FA在全球范围内患者规模日益扩大为背景,综述了肠道菌群影响FA的部分机制,总结了近年部分益生菌和益生元在治疗和预防婴幼儿FA方面的应用,并为肠道菌群在FA发生和发展中的作用机制研究和益生菌及其相关代谢产物在儿童FA治疗和预防中的应用提出了新思路,对促进婴幼儿FA治疗方法和策略的研究有重要意义。     

Toll-like receptor (TLR2, TLR4 and TLR5) gene polymorphisms and Helicobacter pylori infection in children with and without duodenal ulcer

Helicobacter pylori infection is mainly acquired in childhood, and polymorphisms in the host genes coding for Toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. Our aim was to investigate whether TLR4, TLR2, and TLR5 polymorphisms were associated with H. pylori susceptibility and risk for duodenal ulcer in children. Gastric biopsy specimens were obtained at endoscopy for evaluation of H. pylori status, TLR4, TLR2 and TLR5 polymorphisms from 486 children (254 H. pylori-negative and 232 H. pylori-positive: 72 with and 160 without duodenal ulcer). cagA status of H. pylori infection was investigated by PCR. The levels of gastric cytokines were detected by ELISA. H. pylori-positivity or duodenal ulcer were not associated with TLR2, TLR4 or TLR5 polymorphisms. Otherwise, the presence of TLR4 polymorphic allele was associated with infection by cagA-positive strains and with increased gastric levels of interleukin-8 and interleukin-10. TLR4 polymorphism might ultimately contribute to more severe consequences of the infection in adulthood since it was associated with susceptibility to cagA-positive H. pylori infection early in life.     

Quality of life in patients with food allergy

Food allergy has increased in developed countries and can have a dramatic effect on quality of life, so as to provoke fatal reactions. We aimed to outline the socioeconomic impact that food allergy exerts in this kind of patients by performing a complete review of the literature and also describing the factors that may influence, to a greater extent, the quality of life of patients with food allergy and analyzing the different questionnaires available. Hitherto, strict avoidance of the culprit food(s) and use of emergency medications are the pillars to manage this condition. Promising approaches such as specific oral or epicutaneous immunotherapy and the use of monoclonal antibodies are progressively being investigated worldwide. However, even that an increasing number of centers fulfill those approaches, they are not fully implemented enough in clinical practice. The mean annual cost of health care has been estimated in international dollars (I$) 2016 for food-allergic adults and I$1089 for controls, a difference of I$927 (95 % confidence interval I$324–I$1530). A similar result was found for adults in each country, and for children, and interestingly, it was not sensitive to baseline demographic differences. Cost was significantly related to severity of illness in cases in nine countries. The constant threat of exposure, need for vigilance and expectation of outcome can have a tremendous impact on quality of life. Several studies have analyzed the impact of food allergy on health-related quality of life (HRQL) in adults and children in different countries. There have been described different factors that could modify HRQL in food allergic patients, the most important of them are perceived disease severity, age of the patient, peanut or soy allergy, country of origin and having allergy to two or more foods. Over the last few years, several different specific Quality of Life questionnaires for food allergic patients have been developed and translated to different languages and cultures. It is important to perform lingual and cultural translations of existent questionnaires in order to ensure its suitability in a specific region or country with its own socioeconomic reality and culture. Tools aimed at assessing the impact of food allergy on HRQL should be always part of the diagnostic work up, in order to provide a complete basal assessment, to highlight target of intervention as well as to evaluate the effectiveness of interventions designed to cure food allergy. HRQL may be the only meaningful outcome measure available for food allergy measuring this continuous burden.     

Sensitization to secretoglobin and lipocalins in a group of young children with risk of developing respiratory allergy

Background

Multiple sensitizations in early age have been reported to be a risk for development of asthma. This study evaluates the emergence and evolution of IgE to aeroallergens among a cohort of children with physician-diagnosed atopic dermatitis and/or showing food allergy symptoms and to examine the relation to asthma development.

Methods

Three-hundred and four children (median age 13.4 months at entry) with food allergy symptoms and/or atopic dermatitis without asthma at inclusion were analysed for IgE antibodies against food-, indoor- and outdoor-allergens and pet allergen components and correlated to the individuals’ outcome on asthma inception.

Results

At 2 years of follow-up, physician-diagnosed asthma was 19.7% (n = 49) and asthma diagnosed any time was 24% (n = 67). History of persistent cough and asthma of father, combination of milk- and wheat-allergy symptoms and dual sensitization to house dust mite and Japanese cedar were independent risk factors for asthma. Sensitization to dog was the most prevalent inhalant allergen at entry. Asthma children had a higher proportion of sensitization to dog, cat and horse allergens at entry compared with non-asthma children. Being sensitized to both food, house dust mite and pet allergens was strongly associated with asthma (p = 0.0006). Component resolved diagnosis for dog and cat allergens showed that IgE antibodies to Can f 1 and Fel d 1 was common even at very young age.

Conclusions

Early sensitization to inhalant allergens increases the risk of developing asthma as well as having milk and wheat allergy symptoms. Sensitization to dog, was common at an early age despite dog ownership. Sensitization to secretoglobin and lipocalins and less to serum albumins explained the pet sensitization.

     

Relationships of inflammatory activity with biochemical parameters of the blood and sympathovagal balance of young athletes

Results of numerous studies show that a specific combination of biochemical parameters is formed in a trained body. The systemic inflammatory activity is supposed to be an integral factor involved in the formation of such a specific biochemical profile. The measurements of biochemical parameters of athletes’ blood and sympathovagal balance (via the assessment of the heart rate variability) performed in this study show that a decreased level of C-reactive protein is correlated with the count of red blood cells, hematocrit, levels of neutrophils and lymphocytes, total concentration of cholesterol and its concentration in low-density lipoproteins, activity of creatine phosphokinase, time of heart rate recovery from 170 to 120 beats/min (the HR_170-120 index), and the LF/HF ratio (regarded as a marker of the sympathovagal balance). Hence, a decreased inflammatory activity can be involved in the regulation of some biochemical parameters and affect the sympathovagal balance of a trained body.     

Epigenome-wide association study reveals longitudinally stable DNA methylation differences in CD4+ T cells from children with IgE-mediated food allergy

Food allergy is mediated by a combination of genetic and environmental risk factors, potentially mediated by epigenetic mechanisms. CD4+ T-cells are key drivers of the allergic response, and may therefore harbor epigenetic variation in association with the disease phenotype. Here we retrospectively examined genome-wide DNA methylation profiles (~450 000 CpGs) from CD4+ T-cells on a birth cohort of 12 children with IgE-mediated food allergy diagnosed at 12-months, and 12 non-allergic controls. DNA samples were available at two time points, birth and 12-months. Case:control comparisons of CD4+ methylation profiles identified 179 differentially methylated probes (DMP) at 12-months and 136 DMP at birth (FDR-adjusted P value < 0.05, delta β > 0.1). Approximately 30% of DMPs were coincident with previously annotated SNPs. A total of 96 allergy-associated non-SNP DMPs were present at birth when individuals were initially disease-free, potentially implicating these loci in the causal pathway. Pathway analysis of differentially methylated genes identified several MAP kinase signaling molecules. Mass spectrometry was used to validate 15 CpG sites at 3 candidate genes. Combined analysis of differential methylation with gene expression profiles revealed gene expression differences at some but not all allergy associated differentially methylated genes. Thus, dysregulation of DNA methylation at MAPK signaling-associated genes during early CD4+ T-cell development may contribute to suboptimal T-lymphocyte responses in early childhood associated with the development of food allergy.     

Epigenome-wide association study reveals longitudinally stable DNA methylation differences in CD4+ T cells from children with IgE-mediated food allergy

Food allergy is mediated by a combination of genetic and environmental risk factors, potentially mediated by epigenetic mechanisms. CD4+ T-cells are key drivers of the allergic response, and may therefore harbor epigenetic variation in association with the disease phenotype. Here we retrospectively examined genome-wide DNA methylation profiles (~450?000 CpGs) from CD4+ T-cells on a birth cohort of 12 children with IgE-mediated food allergy diagnosed at 12-months, and 12 non-allergic controls. DNA samples were available at two time points, birth and 12-months. Case:control comparisons of CD4+ methylation profiles identified 179 differentially methylated probes (DMP) at 12-months and 136 DMP at birth (FDR-adjusted P value < 0.05, delta β > 0.1). Approximately 30% of DMPs were coincident with previously annotated SNPs. A total of 96 allergy-associated non-SNP DMPs were present at birth when individuals were initially disease-free, potentially implicating these loci in the causal pathway. Pathway analysis of differentially methylated genes identified several MAP kinase signaling molecules. Mass spectrometry was used to validate 15 CpG sites at 3 candidate genes. Combined analysis of differential methylation with gene expression profiles revealed gene expression differences at some but not all allergy associated differentially methylated genes. Thus, dysregulation of DNA methylation at MAPK signaling-associated genes during early CD4+ T-cell development may contribute to suboptimal T-lymphocyte responses in early childhood associated with the development of food allergy.     

Role of IL-4 in aversion induced by food allergy in mice

To ascertain the role of IL-4 in aversion to antigen induced by food allergy, wild type and IL-4 deficient BALB/c mice were sensitized with ovalbumin and challenged orally with egg white. Sensitized wild type mice had increased production of IL-4 by spleen and mesenteric lymph node cells in vitro, higher levels of serum anti-ovalbumin IgE and IgG1, aversion to ingestion of the antigen and loss of body weight after continuous oral challenge. Intestinal changes in wild type sensitized mice included eosinophil infiltration and increased mucus production. The IL-4 deficiency impaired the development of food allergy and the aversion to antigen, suggesting the involvement of the antigen specific antibodies. When IL-4 deficient mice received serum from sensitized wild type donors, the aversion was restored. These results indicate that production of IL-4 and specific IgE/IgG1 antibodies correlate with aversion to antigen induced by food allergy in mice.     

Downregulation in aquaporin 4 and aquaporin 8 expression of the colon associated with the induction of allergic diarrhea in a mouse model of food allergy

Food allergies have become increasingly prevalent during the past few decades. Diarrhea is one of the most frequent intestinal symptoms caused by food allergens and is characterized by imbalanced ion exchange and water transfer; however, the underlying mechanism of allergic diarrhea remains unclear. Water transfer across the intestinal epithelial membrane seems to occur via aquaporins (AQPs). However, the molecular mechanism of water transfer and the pathophysiological roles of aquaporins in the intestine have not been fully established. The present studies have focused on the alterations of AQPs in a mouse model of allergic diarrhea in which BALB/c mice developed diarrhea following repeated challenges of orally administered ovalbumin. Quantitative real-time PCR analysis and immunohistochemical technique were used for expression of mRNA and protein of AQPs, respectively. AQP4 and AQP8 mRNA levels were significantly decreased in the proximal colon of allergic mice compared to controls; likewise, expression of AQP4 and AQP8 proteins was reduced in the proximal colon of the allergic mice. These results suggest that allergic diarrhea is associated with a downregulation in AQP4 and AQP8 expression.     

食物过敏患儿肠道菌群特征及其与外周血Treg/Th17的相关性

分析食物过敏患儿肠道菌群分布与外周血免疫细胞Treg/Th17的关系。

选择2020年4月至2022年5月本院儿科收治的86例食物过敏患儿作为观察组,另选择同期80例健康儿童作为健康对照组。采集两组儿童新鲜粪便和外周血样本,分别测定肠道菌群数量以及外周血Treg/Th17细胞、血清相关细胞因子水平,并经Pearson相关性分析肠道菌群与外周血Treg/Th17的相关性。

观察组患儿肠道内乳杆菌、双歧杆菌数量均低于健康对照组（均P＜0.05）;观察组患儿外周血内Treg细胞水平、Treg/Th17比值均低于健康对照组,但Th17细胞水平高于健康对照组（均P＜0.05）;观察组患儿的血清白细胞介素-17（interleukin-17,IL-17）水平高于健康对照组,血清转化生长因子-β1（transforming growth factor-β1,TGF-β1）指标低于健康对照组（均P＜0.05）;Pearson相关性分析结果显示,乳杆菌、双歧杆菌与外周血Treg细胞、TGF-β1水平均呈正相关,而与外周血Th17细胞、IL-17水平均呈负相关（均P＜0.05）。

食物过敏患儿伴显著的肠道菌群紊乱与免疫功能异常状况,肠道内乳杆菌和双歧杆菌水平以及外周血Treg细胞、TGF-β1表达减少,外周血Th17细胞、IL-17表达增多。临床应改善患儿肠道微生态环境,调控肠道菌群结构,促进肠道菌群分布平衡恢复。