Gibberellin-regulated proteins: Emergent allergens

Comprehensive review of pollen-food allergy syndrome: Pathogenesis, epidemiology, and treatment approaches

Pollen-food allergy syndrome (PFAS) is caused by cross-reaction of a specific pollen antigen with the corresponding food allergen in sensitized individuals. The manifestations are usually limited to oral symptoms; however, sometimes, rhinitis, respiratory and skin symptoms, and anaphylactic shock may occur. In PFAS pathogenesis, when food containing protein antigens (pan-allergens) with high homology to pollen antigens is ingested, mast cells bound to pollen antigen-specific IgE distributed in the oral mucosa cross-react with the food antigen, causing a local type I allergic reaction. The prevalence of PFAS depends on the geographic conditions, such as the type and amount of pollen in the area. PFAS is prevalent in all regions owing to the wide variety of pollen antigens implicated in the disease, such as alder and grass pollen, even outside of the birch habitat area. Basic research on PFAS is expected to significantly contribute to elucidating the pathogenesis and development of therapeutic strategies for PFAS. Currently, effective treatment for patients with PFAS that allows safe consumption of raw foods is lacking, and avoiding the intake of causative foods is the basis of prevention. Furthermore, allergen immunotherapy for PFAS has not yet been established, but various attempts are underway to develop it into a novel treatment strategy. This review highlights the current research landscape on the pathophysiology, epidemiology, and clinical aspects of PFAS. We outline the research gaps that should be addressed to improve the outcomes of patients with PFAS.

Chinese expert consensus on allergen component resolved diagnosis

BACKGROUND

Allergen component resolved diagnosis (CRD) is a method for identifying specific protein molecules that cause hypersensitivity. Unlike traditional methods that use crude allergen extracts containing multiple component species, CRD focuses on individual allergen protein molecules for more precise diagnosis. The World Allergy Organization (WAO) recommends CRD as a supplement to clinical history and allergen extract testing, and in some cases, it can replace crude extract tests.

METHODS

CRD involves the use of natural or recombinant proteins to detect specific IgE antibodies directed at individual allergenic components. This method allows for a more detailed analysis of a patient's allergic response compared to the use of whole allergen extracts. The Allergy Prevention and Control Specialty Committee of the Chinese Preventive Medicine Association, in collaboration with multidisciplinary experts, developed an expert consensus that incorporates the consensus of the European Academy of Allergy and Clinical Immunology (EAACI), WAO, and important domestic literature on CRD in recent years.

RESULTS

The consensus aims to standardize the algorithm of allergen diagnosis and provides a reference for clinical practice. It also offers guidance for clinicians on the common protein families identified by CRD, the scenarios where CRD is applicable, and the significance of detecting common allergen components.

CONCLUSIONS

Despite its potential, CRD is not widely used in clinical practice in China due to the lack of allergen component reagents and a general unawareness among clinicians about CRD's application and interpretation of test results. The expert consensus developed by the Chinese Preventive Medicine Association aims to address this gap and enhance the clinical application of CRD in China.

Screening of IgE-Binding Epitopes of Peach Allergenic Protein Pru p 7 Based on an Immune Microarray Assay

Pru p 7 (also named Peamaclein) is a member of the gibberellin-regulated protein family, which is the latest foodborne allergenic protein identified in peach. In this paper, the prokaryotic expression and identification of Pru p 7 were performed, and the protein properties, structure, and homology were analyzed. In addition, a preliminary screening of B-cell linear epitopes of Pru p 7 was performed by the bioinformatics software prediction method, and three epitopes were identified using slot-blot immune microarray assay combined with an immune score matrix (P-1, AA16-21, AGYQER; P-2, AA40-46, TYGNKDE; P-3, AA52-59, DLKNSKGN). Moreover, the electrostatic potential of these epitopes was analyzed, and the stability after ultrahigh pressure treatment was also verified. Finally, the amino acids that play key immune roles in the epitopes were obtained by amino acid mutations. These results may contribute to the further understanding of Pru p 7 and the prevention of peach allergy.

Food-triggered anaphylaxis in adults

PURPOSE OF REVIEW

Adult food allergy, either unresolved from childhood, or new-onset in adult-life, is known to be increasingly prevalent. Although much of the reported anaphylaxis in adults is due to drug reactions, foods are becoming an increasingly important trigger, affecting adults of all ages, with a wide variation in food triggers which are often quite different to those reported in children.

RECENT FINDINGS

Peanuts are well known to cause anaphylaxis in some adult populations, but other legumes such as soy may be more relevant in others. Reactions to natto, fermented soybeans, are currently mainly reported in Japan, but changing dietary practices and an increase in plant-based eating mean natto, other forms of soy and other legumes are increasingly linked to anaphylaxis in Western countries. Anaphylaxis to red meat, caused by sensitization to galactose-α-1,3-galactose and first reported in North America, is now a more world-wide concern. Co-factor induced anaphylaxis is increasingly associated with both wheat allergy and lipid transfer protein allergy.

SUMMARY

More research is urgently needed to characterize adult food allergy, its triggers and symptom severity. Unusual food triggers and potential co-factors should be considered, so that anaphylaxis in adults can be correctly managed, not merely labelled as idiopathic.

What molecular allergy teaches us about genetics and epidemiology of allergies

PURPOSE OF REVIEW

To delineate pertinent information regarding the application of molecular allergology within the realm of both genetic and epidemiological facets of allergic diseases.

RECENT FINDINGS

The emergence of molecular allergy has facilitated the comprehension of the biochemical characteristics of allergens originating from diverse sources. It has allowed for the exploration of sensitization trajectories and provided novel insights into the influence of genetics and environmental exposure on the initiation and development of allergic diseases. This review delves into the primary discoveries related to the genetics and epidemiology of allergies, facilitated by the application of molecular allergy. It also scrutinizes the impact of environmental exposure across varied geoclimatic, socioeconomic, and lifestyle contexts. Additionally, the review introduces specific models of molecular allergy within the realms of plants and animals.

SUMMARY

The utilization of molecular allergy in clinical practice holds crucially acknowledged diagnostic and therapeutic implications. From a research standpoint, there is a growing need for the widespread adoption of molecular diagnostic tools to achieve a more profound understanding of the epidemiology and natural progression of allergic diseases.

Impact of gibberellin-regulated protein allergy on quality of life

The purpose of this study was to investigate possible allergens that cause gibberellin-regulated protein allergy. For this purpose, a thorough search of relevant information in the databases Embase, PubMed, Scopus, and Web of Science, presented for 2018-2023, was carried out. The study showed that about 4% of the world’s population suffers from food allergies. The main manifestations of allergic reactions and the degree of resistance to allergens depend on the age group of patients. The study identified the following food allergens in gibberellin-regulated protein allergy: Pru p7 (peach), Pru m7 (Japanese apricot), Cit s7 (orange), Pun g7 (pomegranate), Pru av7 (sweet cherry), Cap a7 (bell pepper), Fra a3 (strawberry), Cup s7 (cypress pollen). Gibberellin-regulated protein allergy is characterised by a predominantly adolescent and young adult population. The symptoms of this allergy usually manifest themselves in the form of oral syndrome, facial swelling (including eyelids), anaphylactic reactions and are aggravated by the action of cofactors. Such manifestations substantially impair the quality of life of patients, causing a social, psychological, and economic burden.

Allergy to Gibberellin-regulated proteins in an adolescent: A case of orange-induced anaphylaxis mediated by cofactors

This report is a case of anaphylaxis in an adolescent due to allergy to gibberellin-regulated proteins mediated by cofactors, in probable relation to a pollen/food allergy syndrome. It should also emphasizes the importance of obtaining a faithful clinical history, especially when it comes to adolescent patients as they tend to initiate toxic habits.

Optimization of the diagnosis and characterization of gibberellin-regulated protein sensitization: An Italian cohort study

BACKGROUND

Pru p 7 was the first gibberellin-regulated protein (GRP) to be identified as a food allergen as the basis of a pollen food allergy syndrome.

OBJECTIVE

To clinically and biologically characterize a group of patients with suspected allergy to Pru p 7 to optimize the diagnostic workup of GRP sensitization.

METHODS

Allergy to Pru p 7 was suspected in the presence of a systemic allergic reaction to plant food, positive skin prick test results for cypress pollen and lipid-transfer protein-enriched peach extract, and absence of Pru p 3-specific immunoglobulin E. Controls were patients with food allergies, patients sensitized to Pru p 3, and patients with cypress allergy without food allergy. Diagnostic workup included skin tests, basophil activation test, Western blot, and single and multiplex assays.

RESULTS

In total, 23 patients and 14 controls were enrolled. The most implicated food was peach (91.3%). Approximately 70% of patients reacted to multiple foods. Mueller 4 reactions were 8.7%. In 26.1% of cases, a cofactor triggered the reaction. The basophil activation test results were positive for rPru p 7 in 87% of the patients. Specific immunoglobulin E to Pru p 7 was detected in 95.7% by singleplex and in 73.9% by multiplex assays in patients with suspected allergies; 73.9% of them also reacted to cypress pollen GRP (Cup s 7) in Western blot analysis.

CONCLUSION

Patients with Pru p 7-Cup s 7 allergy in our cohort confirm a mild-to-severe clinical syndrome characterized by pollen and food allergy. The diagnosis may benefit from the proposed selection criteria that can be used as preliminary steps to further characterize the cross-reactive GRP sensitization.

Revisiting Fruit Allergy: Prevalence across the Globe, Diagnosis, and Current Management

Fruit allergies manifest with a diverse array of clinical presentations, ranging from localized contact allergies and oral allergy syndrome to the potential for severe systemic reactions including anaphylaxis. The scope of population-level prevalence studies remains limited, largely derived from single-center or hospital-based investigations. In this comprehensive review, we conducted a systematic literature search spanning the years 2009 to 2023, with full acknowledgment of potential analytical biases, to provide a global overview of fruit allergy prevalence. The primary mechanistic underpinning of fruit allergies stems from cross-reactivity between aeroallergens and food allergens, a consequence of structurally similar epitopes-a phenomenon recognized as pollen food allergy syndrome (PFAS). In the era of molecular allergology, numerous studies have dissected allergen components with substantial clinical relevance. Within this review, we explore important allergenic molecules found in plant-based foods, scrutinize pertinent cross-reactivity patterns, and offer insights into management recommendations. Additionally, we compare guideline recommendations to enhance clinical understanding and inform decision making.

New arrivals in anaphylaxis to foods

PURPOSE OF REVIEW

More people are excluding wheat from their diet, or turning to a more sustainable diet in which includes meat substitutes or is mainly or wholly plant-based. This increases the availability of new foods and with it the increasing likelihood of novel allergens.

RECENT FINDINGS

There is a growing body of evidence which suggests that allergies to seeds and legumes are increasing potentially due to their use in concentrated form in vegan or health foods. Insects can be a sustainable source of protein, but mealworm could provoke symptoms in individuals sensitized or allergic to shellfish or house dust mite. Novel plant food allergens such as gibberellin-regulated proteins and thaumatin-like proteins are increasingly being reported as significant causes of severe reactions to fruits.

SUMMARY

these findings make it even more imperative to take a full dietary history to ensure apparent idiopathic anaphylaxis is not in reality due to a novel food, especially in cases where other forms of the food are tolerated. Given the lack of diagnostic tests for these novel foods, a prick-to-prick skin prick test should be performed with the suspected food. There is currently more work needed to define and sequence many of the allergens involved.

Molecular allergology and its application in prevention, diagnosis and therapy

Allergic diseases represent a relevant global health problem, affecting adults and children and posing a significant burden for health care systems. In addition, the disease is still under-recognized and harmonized diagnostic tools and management plans for patients are still lacking. In this review the most important aspects of the diagnosis of allergic diseases are summarized and the contribution of Molecular allergology to this area is highlighted.

Application of AllerCatPro 2.0 for protein safety assessments of consumer products

Foreign proteins are potentially immunogenic, and a proportion of these are able to induce immune responses that result in allergic sensitization. Subsequent exposure of sensitized subjects to the inducing protein can provoke a variety of allergic reactions that may be severe, or even fatal. It has therefore been recognized for some time that it is important to determine a priori whether a given protein has the potential to induce allergic responses in exposed subjects. For example, the need to assess whether transgene products expressed in genetically engineered crop plants have allergenic properties. This is not necessarily a straightforward exercise (as discussed elsewhere in this edition), but the task becomes even more challenging when there is a need to conduct an overall allergenicity safety assessment of complex mixtures of proteins in botanicals or other natural sources that are to be used in consumer products. This paper describes a new paradigm for the allergenicity safety assessment of proteins that is based on the use of AllerCatPro 2.0, a new version of a previously described web application model developed for the characterization of the allergenic potential of proteins. Operational aspects of AllerCatPro 2.0 are described with emphasis on the application of new features that provide improvements in the predictions of allergenic properties such as the identification of proteins with high allergenic concern. Furthermore, the paper provides a description of strategies of how AllerCatPro 2.0 can best be deployed as a screening tool for identifying suitable proteins as ingredients in consumer products as well as a tool, in conjunction with label-free proteomic analysis, for identifying and semiquantifying protein allergens in complex materials. Lastly, the paper discusses the steps that are recommended for formal allergenicity safety assessment of novel consumer products which contain proteins, including consideration and integration of predicted consumer exposure metrics. The article therefore provides a holistic perspective of the processes through which effective protein safety assessments can be made of potential allergenic hazards and risks associated with exposure to proteins in consumer products, with a particular focus on the use of AllerCatPro 2.0 for this purpose.

Binding to Iron Quercetin Complexes Increases the Antioxidant Capacity of the Major Birch Pollen Allergen Bet v 1 and Reduces Its Allergenicity

Bet v 1 is the major allergen in birch pollen to which up to 95% of patients sensitized to birch respond. As a member of the pathogenesis-related PR 10 family, its natural function is implicated in plant defense, with a member of the PR10 family being reported to be upregulated under iron deficiency. As such, we assessed the function of Bet v 1 to sequester iron and its immunomodulatory properties on human immune cells. Binding of Bet v 1 to iron quercetin complexes FeQ2 was determined in docking calculations and by spectroscopy. Serum IgE-binding to Bet v 1 with (holoBet v1) and without ligands (apoBet v 1) were assessed by ELISA, blocking experiments and Western Blot. Crosslinking-capacity of apo/holoBet v 1 were assessed on human mast cells and Arylhydrocarbon receptor (AhR) activation with the human reporter cellline AZ-AHR. Human PBMCs were stimulated and assessed for labile iron and phenotypic changes by flow cytometry. Bet v 1 bound to FeQ2 strongly with calculated Kd values of 1 nm surpassing affinities to quercetin alone nearly by a factor of 1000. Binding to FeQ2 masked IgE epitopes and decreased IgE binding up to 80% and impaired degranulation of sensitized human mast cells. Bet v 1 facilitated the shuttling of quercetin, which activated the anti-inflammatory AhR pathway and increased the labile iron pool of human monocytic cells. The increase of labile iron was associated with an anti-inflammatory phenotype in CD14+monocytes and downregulation of HLADR. To summarize, we reveal for the first time that FeQ2 binding reduces the allergenicity of Bet v 1 due to ligand masking, but also actively contributes anti-inflammatory stimuli to human monocytes, thereby fostering tolerance. Nourishing immune cells with complex iron may thus represent a promising antigen-independent immunotherapeutic approach to improve efficacy in allergen immunotherapy.