An epidemiological investigation of food allergy among children aged 3 to 6 in an urban area of Wenzhou, China

Cross-reactivity and conserved epitope analysis of tropomyosin from Lateolabrax japonicus and shellfish species

The phenomenon of cross-reactivity within TM between fish and shellfish has received scant attention. In the study, TM of Lateolabrax japonicus, Scylla paramamosain and Mactra quadrangularis were considered as research objects. The results indicated L. japonicus TM exhibited weak binding for both rabbit anti-S. paramamosain/M. quadrangularis TM antibody. However, a significant IgE-binding capacity was observed for three TM in 11 of 18 fish-sensitised patients. Additionally, three TM also could activated basophils in 6 fish-sensitised patients. Subsequently, seven IgE epitopes of L. japonicus TM were confirmed. Two conserved epitopes (LERTEERA, LKTVQNN) and four critical amino acids (E, A, L, and R) were found across L. japonicus and shellfish TM, suggesting these could be responsible for cross-reactivity. These findings were expected to reduce the allergenicity of fish by destroying IgE epitopes through food processing or deleting IgE epitopes using molecular biotechnology, which have important implications for food safety and allergy management.

Towards an optimized model of food allergy in zebrafish

BACKGROUND

The prevalence of food allergies is on the rise, posing a significant challenge to public health. Rodents serve as the predominant animal model in food allergy research; yet, the application of rodent models proves to be a laborious and time-consuming endeavor. It is imperative to develop novel in vivo models.

METHODS

Ovalbumin (OVA) was administered as the allergen, following the recommended dosage used in other species. During the sensitization phase, a dosage of 0.25 mg per 10 tails per 1 L was administered twice daily, and during the challenge phase, the dosage was increased to 3 times the initial level. The study explored two dimensions of sensitization: the mode of exposure, which can be either continuous or intermittent, and the duration of exposure, which includes 3 days, 5 days, and 7 days. We examined midgut pathological changes, immunoglobulins contents, and mRNA expressions associated to T helper cells (Th) 2 cytokines following exposure.

RESULTS

A significant 109.3 % increase in the number of eosinophils was observed in the midgut histopathology following intermittent 5-day OVA exposure, which emerged as the most effective model. OVA exposure increased concentrations of immunoglobulin M (IgM) (105.2 %), IgZ (312.1 %), and IgD (304.3 %) in this model. The mRNA expressions of Th2-related interleukin (IL)-4 and IL-13 were also elevated by 132.8 % and 421.0 %, respectively.

CONCLUSION

The intermittent 5-day OVA exposure was suggested to be the best constructed zebrafish food allergy model, which may be a potential tool for research into food allergies.

Food allergy in a changing dietary landscape: A focus on the Asia Pacific region

Recent studies have provided compelling evidence to suggest that various environmental factors play a significant role in the development of food allergies. As our society experiences rapid economic growth, increased urbanization, and a shift towards a more Westernized diet, the incidence of food allergies is also on the rise and the pattern is gradually evolving. This review will delve into the changes in the epidemiology of food allergies within the Asia-Pacific region and the various dietary practices and factors that are postulated to play a role in the rise in food allergies over the years. Although there have been important advancements in the field of food allergies, there are still numerous uncertainties regarding the intricate relationship between diet and food allergies. Specifically, the role of epigenetic factors in influencing the susceptibility to food allergies, as evidenced by studies that assessed the impact of migration and rural-urban dynamics, is not fully understood. Addressing this knowledge gap presents an opportunity to develop more effective prevention and treatment strategies that could greatly benefit individuals living with food allergies.

Early-life gut microbiota in food allergic children and its impact on the development of allergic disease

BACKGROUND

The prevalence of food allergies (FA) has been steadily increasing over 2 to 3 decades, showing diverse symptoms and rising severity. These long-term outcomes affect children's growth and development, possibly linking to inflammatory bowel disease. However, the cause remains unclear. Previous studies reveal that early infancy significantly impacts FA development through gut microbiota. Yet, a consistent view on dysbiosis characteristics and its connection to future allergies is lacking. We explored how early-life gut microbiota composition relates to long-term clinical signs in children with FA through longitudinal research.

METHODS

We employed high-throughput 16S rDNA gene sequencing to assess gut microbiota composition in early-life FA children in southern Zhejiang. Follow-up of clinical manifestations over 2 years allowed us to analyze the impact of early-life gut microbiota dysbiosis on later outcomes.

RESULTS

While the diversity of gut microbiota in FA children remained stable, there were shifts in microbiota abundance. Abundant Akkermansia, Parabacteroides, Blautia, and Escherichia-Shigella increased, while Bifidobacterium and Clostridium decreased. After 2 years, two of ten FA children still showed symptoms. These two cases exhibited increased Escherichia-Shigella and reduced Bifidobacterium during early childhood. The other eight cases experienced symptom remission.

CONCLUSIONS

Our study suggests that FA and its prognosis might not correlate with early-life gut microbiota diversity. Further experiments are needed due to the small sample size, to confirm these findings.

Prevalence of Parent-Reported Food Allergy in a Mexican Pre-School Population

The magnitude and relevance of food allergies in the preschool population remain unknown in most regions of Mexico and Latin America. Thus, our aim was to estimate the parent-reported prevalence of food allergies in a Mexican preschool population and to characterize their clinical diagnosis and presentation. A cross-sectional survey was conducted in Culiacán City. A validated questionnaire was utilized. A total of 810 parents responded to the questionnaire (valid response rate, 40.7%). The estimated prevalence rates (95% CI) were: "physician-diagnosed Food Allergy (FA), ever" 5.30% (3.86-7.08); "immediate-type FA, ever" 2.96% (1.91-4.38); "immediate-type FA, current" 1.60% (0.86-2.73); and food-dependent anaphylaxis 1.11% (0.51-2.01). The main food allergens were milk (0.49%), strawberries (0.37%), egg, and soy (0.25% each). Atopic diseases and a family history of allergies were significantly associated with immediate-type FA. Among "immediate-type FA, current" cases, 76.9% required emergency room visits, but the prescription of epinephrine autoinjectors was reported in one case only. The food reactions occurred at home (92.35%), in a relative's house (38.5), and at restaurants (23%). Immediate-type FA reactions requiring emergency room visits are not uncommon among the studied population. Actions like proper anaphylaxis management and the prevention of cross-contamination of foods should be encouraged.

IgE Mediated Shellfish Allergy in Children-A Review

Shellfish is a leading cause of food allergy and anaphylaxis worldwide. Recent advances in molecular characterization have led to a better understanding of the allergen profile. High sequence homology between shellfish species and between shellfish and house dust mites leads to a high serological cross-reactivity, which does not accurately correlate with clinical cross-reactions. Clinical manifestations are immediate and the predominance of perioral symptoms is a typical feature of shellfish allergy. Diagnosis, as for other food allergies, is based on SPTs and specific IgE, while the gold standard is DBPCFC. Cross-reactivity between shellfish is common and therefore, it is mandatory to avoid all shellfish. New immunotherapeutic strategies based on hypoallergens and other innovative approaches represent the new frontiers for desensitization.

Allergic sensitization to foods in India and other Low-Middle-income countries

Food allergy is an important cause of morbidity, significantly affecting the quality of life of the sufferer. Most food allergy research has been undertaken in high-income countries. Here, we summarize literature regarding food allergy in India and other low-middle-income countries (LMIC). We provide summaries of self-reported adverse food reactions and food sensitization in these regions by reviewing published community-based studies of prevalence, burden, and risk factors. We identified 2 community-based studies of food allergy prevalence in Karnataka, India, which estimate that food allergy affects just 0.14% of children and 1.2% of adults. The overall prevalence of allergic sensitization to 'any' food was 26.5% in adults and 19.1% in children by serum-specific IgE; but only 4.48% in children by skin prick test. We identified a further 28 studies in other LMICs, mainly from China but also Turkey, South Africa, Ghana, Mexico, Brazil, Thailand, Philippines, and Korea. The overall prevalence of allergic sensitization to 'any' food ranged from 0.11% to 16.8% in children using serum-specific IgE and 0.14% to 9.6% in children by skin prick test. The questionnaires and skin prick testing materials used and number of allergens tested varied significantly between studies. Other than Karnataka, there is no information on prevalence of food sensitization and probable food allergy in the community in India. Similar lack of information is noted among the majority of the 136 LMICs. Where community-based studies have been undertaken, there is wide variation in the prevalence and patterns of food sensitization across different LMICs, at least partly due to variations in study methodology. International collaboration is required in order to formally assess food allergy prevalence and burden across representative samples from multiple LMICs.

Nutritional Management of Children with Food Allergies

Purpose of the Review

The purpose of the review is to review the evidence for the nutritional management of paediatric food allergy and provide a practical approach for healthcare professionals working in this area.

Recent Findings

Dietary elimination remains the mainstay for management of food allergies in children. However, the elimination of food allergens increases the risk for growth faltering, micronutrient deficiencies and feeding difficulties. Breastmilk remains the ideal source of nutrition for infants, but when not available, the vast majority will tolerate an extensively hydrolysed formula, and rice hydrolysate has also been suggested as a suitable alternative. Only in severe cases, including anaphylaxis, eosinophilic oesophagitis and growth faltering, is an amino acid formula indicated. The early introduction of peanut and egg and avoiding the delay in the introduction of other allergens, when not already allergic, has been highlighted by recent studies.

Summary

Whilst the elimination of allergens increases the risk of developing poor growth, micronutrient deficiencies and feeding difficulties, optimal, early dietary input, including advice on active introduction of allergens and alternative feeds, ideally from a registered dietitian/nutritionist, may be prevent and improve outcomes.

Multi-Perspective Observation on the Prevalence of Food Allergy in the General Chinese Population: A Meta-Analysis

Reliable estimates of the prevalence of food allergy (FA) among the general Chinese population have remained unclear. This meta-analysis aims to provide an accurate estimate of FA prevalence in China with comprehensive data. A systematic literature search was conducted in eight electronic databases, i.e., China National Knowledge Infrastructure, Wanfang, Weipu, China Biology Medicine, Web of Science, PubMed, Cochrane, and Embase. A random-effects model was used to analyze the pooled prevalence of FA for four different assessment methods. A total of 46 eligible articles were included in the narrative synthesis, and 41 articles were ultimately included in the meta-analysis. Overall, the pooled prevalence of self-reported FA, self-reported physician-diagnosed FA, SPT (specific skin prick test)-positive FA, and OFC (open food challenge)-positive FA were 11.5% (95% CI: 9.8-13.5%), 5.3% (95% CI: 4.2-6.5%), 11.6% (95% CI: 9.6-14.1%), and 6.2% (95% CI: 4.4-8.7%), respectively. Subgroup analyses suggested that the prevalence of FA was affected by age, year of data collection, region, and sample size, but not by gender. This meta-analysis indicated that FA is common among Chinese people, with an increasing trend in prevalence during the past two decades. Given the high heterogenicity between these studies, a national survey with a large sample size based on standardized diagnosis is urgently needed to gain a more scientific understanding of the actual situation of food allergy in China.

Food allergy across the globe

The prevalence of food allergy (FA) is increasing in some areas of the globe, highlighting the need for better strategies for prevention, diagnosis, and therapy. In the last few decades, we have made great strides in understanding the causes and mechanisms underlying FAs, prompting guideline updates. Earlier guidelines recommended avoidance of common food allergens during pregnancy and lactation and delaying the introduction of allergenic foods in children aged between 1 and 3 years. Recent guidelines for allergy prevention recommend consumption of a healthy and diverse diet without eliminating or increasing the consumption of allergenic foods during pregnancy or breast-feeding. Early introduction of allergenic foods is recommended by most guidelines for allergy prevention after a period of exclusive breast-feedng (6 months [World Health Organization] or 4 months [European Academy of Allergy and Clinical Immunology]). New diagnostics for FA have been developed with varied availability of these tests in different countries. Finally, the first oral immunotherapy drug for FA was approved by the US Food and Drug Administration and European Medicines Agency in 2020. In this review, we will address the global prevalence of FA, our current understanding of the causes of FA, and the latest guidelines for preventing, diagnosing, and treating FA. We will also discuss similarities and differences between FA guidelines.

Seafood Allergy in Asia: Geographical Specificity and Beyond

Asian countries have unique ways of food processing and dietary habits that may explain the observed differences in the prevalence, natural history, epidemiology and sensitization pattern of food allergic diseases when compared to western countries. Per capita consumption of seafood, including fish and shellfish, is well above the global average for many Asian countries because of their coastal geographical location and rich seafood supply. The wide availability and high abundance of seafood in Asian countries have shaped a diverse way of processing and eating this major food group. Such unique features have significant impact on the sensitization profile and allergenicity of Asians to fish and shellfish. For example, fish and shellfish are eaten raw in some countries that may promote sensitization to heat-labile allergens not otherwise seen in other regions. Fermented fish sauce is commonly used as a condiment in some countries which may promote fish sensitization. Shrimp head and shrimp roe are regarded as delicacies in some countries, but their allergen profiles are yet to be characterized. Freshwater fish and shellfish are a common food source in many Asian countries but the allergenicity of many such species remains unknown. In this review, we discuss factors that may contribute to differences in molecular profile and sensitization pattern for fish and shellfish that are observed in Asian populations and revisit the current status of seafood allergy in this part of the world. Acknowledging the similarities and differences of seafood allergy patterns between Asian and western populations can help us refine a better strategy for diagnosing and managing seafood allergy.

Alteration of Intestinal Microbiota Composition in Oral Sensitized C3H/HeJ Mice Is Associated With Changes in Dendritic Cells and T Cells in Mesenteric Lymph Nodes

This research aimed to investigate the allergic reaction of C3H/HeJ mice after sensitization with ovalbumin (OVA) without any adjuvant and to analyze the association between intestinal microbiota and allergy-related immune cells in mesenteric lymph nodes (MLN). The allergic responses of C3H/HeJ mice orally sensitized with OVA were evaluated, and immune cell subsets in spleen and MLN and cytokines were also detected. The intestinal bacterial community structure was analyzed, followed by Spearman correlation analysis between changed gut microbiota species and allergic parameters. Sensitization induced a noticeable allergic response to the gavage of OVA without adjuvant. Increased levels of Th2, IL-4, CD103⁺CD86⁺ DC, and MHCII⁺CD86⁺ DC and decreased levels of Th1, Treg, IFN-γ, TGF-β1, and CD11C⁺CD103⁺ DC were observed in allergic mice. Furthermore, families of Lachnospiraceae, Clostridiaceae_1, Ruminococcaceae, and peprostreptococcaceae, all of which belonging to the order Clostridiales, were positively related to Treg and CD11C⁺CD103⁺ DC, while they were negatively related to an allergic reaction, levels of Th2, CD103⁺CD86⁺ DC, and MHCII⁺CD86⁺ DC in MLN. The family of norank_o_Mollicutes_RF39 belonging to the order Mollicutes_RF39 was similarly correlated with allergic reaction and immune cells in MLN of mice. To sum up, allergic reactions and intestinal flora disturbances could be induced by OVA oral administration alone. The orders of Clostridiales and Mollicutes_RF39 in intestinal flora are positively correlated with levels of Treg and CD11C⁺CD103⁺ DC in MLN of mice.

CURRENT TRENDS IN THE PREVALENCE OF FOOD HYPERSENSITIVITY IN CHILDREN OF THE KYIV REGION

The aim of the study. Due to the growing prevalence of food hypersensitivity worldwide and the number of dangerous food reactions, the aim was to determine the current prevalence of food hypersensitivity symptoms among children in the Kyiv region, Ukraine. Methods. Total of 7106 children were surveyed: Group I (4 months – 5 years) had 1787 children, Group II (6–7 years) – 2080 children, Group ІІI (13–14 years) – 1909 children, Group ІV (15–17 years) – 1330 children. Results. The prevalence of food hypersensitivity among the surveyed children is 26.5 % (95 % CI: 25.5–27.6) – this is 1888 children out of 7106. Highest prevalence of food hypersensitivity (FHS) is observed in the Group I, which is 32 % (95 % CI: 29.8–34.2) – 571/1787, Groups II – 27.2 % (95 % CI: 25.7–29.8) – 566/2080, Groups III – 27.7 % (95 % CI: 14.7–18.0) – 529/1909, in the Group IV – 16.7 % (95 % CI: 25.3-29.2) – 222/1330). FHS in children is most often manifested by skin symptoms, followed by gastrointestinal manifestations, and acute urticaria/angioneurotic edema is at the third place. Respiratory manifestations possess 5 % in the structure of FHS symptoms. An anaphylactic reaction was observed in 4 children out of 7106 respondents. Conclusions. The prevalence of food hypersensitivity among Ukrainian children is high. There is an increase in the prevalence of urticaria/angioedema in preschool children.