Natural rubber latex and chestnut allergy: cross-reactivity or co-sensitization?

Revisiting Latex-Fruit Syndrome after 30 Years of Research: A Comprehensive Literature Review and Description of Two Cases

Thirty years have passed since the concept of latex-fruit syndrome (LFS) was first introduced. Since then, this phenomenon, characterized by cross-reactivity between natural latex rubber allergens and certain fruit allergens, has been extensively studied. This literature review sought to determine the prevalence of LFS in latex-allergic patients, identify the most common cross-reactions with fruit allergens in individuals with LFS, and understand the clinical manifestations of this syndrome. An extensive literature search was carried out using PubMed and Scopus databases, while applying the Preferred Reporting Items for Systematic Reviews and Meta-Analysis methodology. The analysis of original studies revealed a wide variation in LFS prevalence (4-88%) influenced by diverse diagnostic tools, different geographical regions, and the size of study populations. Our findings indicate that the most prevalent allergenic fruits in patients with LFS are banana, avocado, kiwifruit, and papaya. After evaluating the symptoms of the fruit hypersensitivity of patients with LFS, the clinical manifestation of hypersensitivity constituted 73% of systemic allergy symptoms and only 27% of reported symptoms described the localized allergy. Furthermore, the clinical picture of latex-fruit syndrome is illustrated through two cases, one typical and one with an unusual presentation. Their clinical features were assessed and contrasted utilizing different anaphylaxis severity grading criteria. To properly manage LFS, it is essential to establish standardized diagnostic criteria and severity grading systems, as these are crucial for accurate diagnosis and effective treatment.

EAACI Molecular Allergology User's Guide 2.0

Since the discovery of immunoglobulin E (IgE) as a mediator of allergic diseases in 1967, our knowledge about the immunological mechanisms of IgE-mediated allergies has remarkably increased. In addition to understanding the immune response and clinical symptoms, allergy diagnosis and management depend strongly on the precise identification of the elicitors of the IgE-mediated allergic reaction. In the past four decades, innovations in bioscience and technology have facilitated the identification and production of well-defined, highly pure molecules for component-resolved diagnosis (CRD), allowing a personalized diagnosis and management of the allergic disease for individual patients. The first edition of the "EAACI Molecular Allergology User's Guide" (MAUG) in 2016 rapidly became a key reference for clinicians, scientists, and interested readers with a background in allergology, immunology, biology, and medicine. Nevertheless, the field of molecular allergology is moving fast, and after 6 years, a new EAACI Taskforce was established to provide an updated document. The Molecular Allergology User's Guide 2.0 summarizes state-of-the-art information on allergen molecules, their clinical relevance, and their application in diagnostic algorithms for clinical practice. It is designed for both, clinicians and scientists, guiding health care professionals through the overwhelming list of different allergen molecules available for testing. Further, it provides diagnostic algorithms on the clinical relevance of allergenic molecules and gives an overview of their biology, the basic mechanisms of test formats, and the application of tests to measure allergen exposure.

Contact Urticaria Syndrome: a Comprehensive Review

Purpose of Review

Contact urticaria syndrome includes contact urticaria and protein contact dermatitis. Underreport, underdiagnosis, or misdiagnosis of entities within the contact urticaria syndrome is believed to be common, especially in the occupational setting. This review provides a structured overview of the entities comprised in this syndrome as well as the diagnostic work-up and management strategies.

Recent Findings

Contact urticaria syndrome has been increasingly described due to personal protective equipment and hand sanitizers in the context of the COVID-19 pandemic. The use of legal cannabis products has led to a rise in occupational cases of contact urticaria to cannabis. A declining trend in the evolution of contact urticaria has been described for natural rubber latex allergy due to the use of synthetic gloves. Prick test has been proposed as a screening method, particularly if multiple products are to be tested, instead of the classical sequential scheme.

Summary

Physicians should be aware of the growing number of culprit agents leading to contact urticaria syndrome. Clinical presentation may be challenging since it includes immediate urticaria and/or eczema and even more generalized reactions. Diagnosis requires a high degree of suspicion, detailed occupational history, and complementary tests, including skin testing. The best treatment is to avoid contact with the culprit agent and to implement preventive measures.

Cross-Reactive Aeroallergens: Which Need to Cross Our Mind in Food Allergy Diagnosis?

Secondary food allergies due to cross-reactivity between inhalant and food allergens are a significant and increasing global health issue. Cross-reactive food allergies predominantly involve plant-derived foods resulting from a prior sensitization to cross-reactive components present in pollen (grass, tree, weeds) and natural rubber latex. Also, primary sensitization to allergens present in fungi, insects, and both nonmammalian and mammalian meat might induce cross-reactive food allergic syndromes. Correct diagnosis of these associated food allergies is not always straightforward and can pose a difficult challenge. As a matter of fact, cross-reactive allergens might hamper food allergy diagnosis, as they can cause clinically irrelevant positive tests to cross-reacting foods that are safely consumed. This review summarizes the most relevant cross-reactivity syndromes between inhalant and food allergens. Particular focus is paid to the potential and limitations of confirmatory testing such as skin testing, specific IgE assays, molecular diagnosis, and basophil activation test.

Allergen component analysis as a tool in the diagnosis and management of occupational allergy

We are now in the epoch of "molecular allergology" and numerous clinically relevant allergenic molecules are available improving the performance of in vitro allergen tests and allergen detection methods. This review is focusing on characterized occupational allergens and their implementation into the in vitro diagnosis for occupational allergy and in allergen detection methods. More than 400 occupational agents are identified and documented as being 'respiratory sensitizers', but currently only a limited number of them are characterized on the molecular level and available for routine diagnosis as native or recombinant allergens. One exception, however, is natural rubber latex (NRL) from Hevea brasiliensis still remaining an important occupational allergen source. Characterization of 15 NRL allergens led to the development of assays for the determination of allergen content of NRL materials and the implementation of component-resolved diagnosis (CRD) for specific IgE antibody measurement. Microarray or singleplex using recombinant or native allergens are reliable tools for NRL allergy diagnosis. In addition, NRL allergy is an excellent model for improving extract-based specific IgE measurement by amplification of NRL extract preparation with stable recombinant major allergen rHev b 5. Despite the many efforts to characterize the occupationally relevant wheat allergens for baker's asthma, the most frequently occurring forms of occupational asthma, the results are highly diverse. Wheat sensitization profiles of bakers showed great interindividual variability and no wheat allergen could be classified as the major allergen. For diagnosis of baker's asthma, a whole wheat extract is still the best option for specific IgE determination. But single wheat allergens might help to discriminate between wheat-induced food allergy, grass pollen allergy and baker's asthma. For workplace-related allergens like coffee, wood, soybean, seafood and moulds allergens are characterized and few of them are available, but their relevance for occupational sensitization routes should be verified in the further studies.

Plant food allergy: Influence of chemicals on plant allergens

Plant-derived foods are the most common allergenic sources in adulthood. Owing to the rapidly increasing prevalence of plant food allergies in industrialized countries, the environmental factors are suspected to play a key role in development of allergic sensitization. The present article provides an overview of ways by which chemicals may influence the development and severity of allergic reactions to plant foods, with especial focus on plant allergens up-regulated under chemical stress. In plants, a substantial part of allergens have defense-related function and their expression is highly influenced by environmental stress and diseases. Pathogenesis-related proteins (PR) account for about 25% of plant food allergens and some are responsible for extensive cross-reactions between plant-derived foods, pollen and latex allergens. Chemicals released by anthropogenic sources such as agriculture, industrial activities and traffic-related air pollutants are potential drivers of the increasing sensitization to allergenic PRs by elevating their expression and by altering their immunogenicity through post-translational modifications. In addition, some orally-taken chemicals may act as immune adjuvants or directly trigger non-IgE mediated food allergy. Taken together, the current literature provides an overwhelming body of evidence supporting the fact that plant chemical exposure and chemicals in diet may enhance the allergenic properties of certain plant-derived foods.

Differentiating of cross-reactions in patients with latex allergy with the use of ISAC test

Introduction

Differentiating between cross-reactivity and double sensitization is still a challenging issue in allergology.

Aim

To differentiate cross-reactions accompanying latex allergy with the use of the ISAC test.

Material and methods

Thirty-nine patients reporting immediate allergic reactions to latex were enrolled into the study (group A). The control group was comprised of 41 patients with allergic diseases not associated with latex (group B) and 20 healthy individuals (group C). Their history was recorded and skin prick tests were performed with latex, airborne and food allergens. Specific IgE against food allergens, latex (k82) and recombined latex allergens were determined. ImmunoCAP ISAC test was performed with 103 molecules.

Results

Sensitization to latex was found by means of skin tests in 16 cases and sIgE against latex was revealed in 12 cases (including 10 positive in both SPT and sIgE). In the ISAC test antibodies against recombined latex allergens were found in 8 patients with rHev b 6 as the most common. All the patients positive for rHev b 1, 5, 6, 8 had allergy or asymptomatic sensitization to food allergens cross-reacting with latex. Some reactions could not have been differentiated due to the lack of allergens in the ISAC test. Others, not related to latex-fruits syndrome were explained by cross-reactivity with other profilins or PR-10 proteins.

Conclusions

ImmunoCAP ISAC test could be useful in differentiating between cross-reactions and double sensitizations. However, in the case of latex its advantages are limited due to a small panel of allergens.

EAACI Molecular Allergology User's Guide

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Microarray-based component-resolved diagnosis of latex allergy: isolated IgE-mediated sensitization to latexprofilin Hev b8 may act as confounder

Immediate type allergy to latex is still a widespread problem. Latex-allergic patients undergoing diagnostic and operative medical procedures are at risk of potentially life-threatening reactions. Accurate diagnostic methods are therefore crucial. The aim of this retrospective study was to discriminate between sensitization and relevant allergy to latex based on an easy and suitable diagnostic approach. In 14 patients with clinical symptoms and 27 controls, latex skin prick tests (SPT), IgE against latex (CAP) and serological component resolved specific latex-allergen determination (Hev b1, b3, b5, b6, b7, b8, b9, b10, b11) based on ImmunoCAP ISAC were performed. SPT correlated very well with clinically manifest latex-allergy demonstrating a high specificity (95%) (and a low sensitivity). However, CAP levels to crude latex could not safely discriminate between purely sensitized and latex-allergic patients. The majority of patients mono-sensitized to the latex profilin Hev b8 did not suffer from any relevant symptoms upon contact with latex. However, in two patients with latex-allergy diagnosed by elevated specific IgE only sensitized against Hev b8, additional sensitization to carbohydrate cross-reactive determinants (CCD) was found. In the case of positive serum IgE against latex and negative SPT, component-resolved diagnosis including IgE against specific latex-proteins, specially Hev b8, and carbohydrate cross-reactive determinants (CCD) is a useful tool to discriminate between latex-sensitization and latex-allergy.

Profilin cross-reactive panallergen causes latex sensitization in the pediatric population allergic to pollen

BACKGROUND

Component-resolved diagnostics (CRD) has been demonstrated to be an excellent new tool for improving the current diagnosis of allergies, and it allows differentiation between polysensitization and cross-reactivity.

OBJECTIVE

To demonstrate the role of cross-reactive pollen allergens in pediatric patients living in areas with large amounts of airborne grass pollen grains who are sensitive to grass pollen and latex.

METHODS

Serum samples were obtained from 106 children between 3 and 14 years of age diagnosed with allergies to pollen based on clinical history, skin prick tests, and specific immunoglobulin E (IgE). None of them had allergy symptoms to latex or fruits. From these 106 children, 56 patients revealed positive results to Phleum-specific major allergens but not to cross-reactive allergens. The other 50 patients who showed positive specific IgE to Phleum-specific major allergens and to cross-reactive pollen allergens also showed positive results to latex allergens. CRD was carried out by specific IgE quantification using a fluoro-enzyme immunoassay (ImmunoCAPT System).

RESULTS

Results demonstrated a positive significant relationship between the specific IgE to Hev b 8 and Phl p 12 and also between the specific IgE to Hev b 8 and latex extract in the group of patients sensitized to species-specific and cross-reactive Phleum allergens. Positive significant relationships were also found between profilin and avocado or peach sensitizations. No other latex allergens gave positive results.

CONCLUSION

The apparent sensitization to latex in pediatric patients allergic to grass pollen is caused by the cross-reactive profilin panallergen; however, it is appears not to be clinically relevant.

Latex-allergic patients sensitized to the major allergen hevein and hevein-like domains of class I chitinases show no increased frequency of latex-associated plant food allergy

Allergies to certain fruits such as banana, avocado, chestnut and kiwi are described in 30–70% of latex-allergic patients. This association is attributed to the cross-reactivity between the major latex allergen hevein and hevein-like domains (HLDs) from fruit class I chitinases. We aimed to assess the extent of cross-reactivity between hevein and HLDs using sera from latex-allergic patients with and without plant food allergy. Hevein and HLDs of latex, banana, and avocado chitinases were expressed in Escherichia coli as fusion proteins with the maltose-binding protein and purified by affinity chromatography. IgE binding to these proteins was studied in sera from 59 latex-allergic patients and 20 banana-allergic patients without latex allergy by ELISA and ELISA inhibition. Additionally, 16,408 allergic patients’ sera were tested for IgE binding to hevein, latex chitinase, and wheat germ agglutinin using an allergen microarray. Hevein-specific IgE was detected in 34/59 (58%) latex-allergic patients’ sera. HLDs of latex, banana, and avocado chitinases were recognized by 21 (36%), 20 (34%), and 9 (15%) sera, respectively. In contrast, only one of 20 banana-allergic patients without latex allergy was sensitized to chitinase HLDs. In most tested latex-allergic patients’ sera, IgE binding to hevein was only partially reduced by preincubation with HLDs. Among hevein-sensitized, latex-allergic patients, the percentage of plant food allergy (15/34 = 44%) was equal to latex-allergic patients without hevein sensitization (11/25 = 44%). In the general allergic population, 230 of 16,408 sera (1.4%) reacted to hevein and/or a hevein-like allergen. Of these, 128 sera showed an isolated sensitization to hevein, whereas only 17 bound to latex chitinase or wheat germ agglutinin without hevein sensitization. In conclusion, the IgE response to HLDs is elicited by hevein as sensitizing allergen in most cases. Despite considerable cross-reactivity between these allergens, no correlation between latex-associated plant food allergy and sensitization to hevein or HLDs was found.

Latex allergy: two educational cases

Natural rubber latex (NRL) allergy is a significant problem both for health care workers and for children with complex medical and surgical conditions that require multiple surgical interventions. Primary and secondary prophylaxis are effective measures in identified high risk groups, such as spina bifida (SB). It is therefore likely that with proper attention to prevention and secondary prophylaxis in the highest risk groups that the numbers of paediatric SB patients with NRL allergy will continue to decrease. In contrast medical awareness of established latex allergy needs to be maintained. The issue of latex sensitisation via fruit and food allergy will also remain, so some of the attention that SB patients have received in the past may need to be refocussed onto other emerging high risk groups. Innovative immunomodulatory approaches may soon translate to the clinic for latex sensitised or allergic subjects.

Gut eosinophilia in food allergy and systemic and autoimmune diseases

Eosinophilic gastroenteritis is a rare disease characterized by striking tissue eosinophilia in any layer of the gut wall; however, many diseases can cause increased gut eosinophilia. Allergic reactions to food are an important cause of gut eosinophilia. Not all adverse reactions to food are IgE mediated, and most cases of IgE-mediated food allergy do not have eosinophilic gastroenteritis. Parasitic, bacterial, and viral pathogens as well as certain systemic diseases such as vasculitis can cause gut eosinophilia. These heterogeneous conditions are reviewed in this article.