Component-resolved Diagnostics Research Articles

Advancing allergy diagnosis in children through component resolved diagnostics in a pediatric tertiary care hospital

Advancing allergy diagnosis in children through component resolved diagnostics in a pediatric tertiary care hospital

Skin tests, serological IgE detection, basophil test—what is available, useful and helps to clarify a mold allergy?

AbstractThe prevalence of sensitization to molds is low in healthy people, but significant in asthmatics. As it has not yet been possible to establish a cause-and-effect relationship between the presence of mold allergens and the occurrence of allergic symptoms, there is a great deal of uncertainty. The update of the S2k guideline “Medical–clinical diagnostics for indoor mold exposure” should help to objectify the topic. Based on the recommendations listed there for the diagnosis of suspected IgE-mediated mold allergy, this article presents the possibilities of skin tests, IgE determinations, and other in vitro test options, but also their limitations in clarifying the cause. Potential possibilities include component-resolved allergy diagnostics, while the limitations include the difficult standardization of test allergen extracts due to the complex allergen source and the insufficient commercial availability of the test extracts. A diagnostic algorithm is presented as a tool for a systematic approach to patients with suspected mold-associated respiratory allergy.

Microfluidic Immunosensing Platform Based on a Rolling Circle Amplification-Assisted DNA Dendrimer Probe for Portable and Sensitive Detection of Allergen-Specific IgE.

The robust point-of-care platform for sensitive, multiplexed, and affordable detection of allergen-specific IgE (sIgE) is an urgent demand in component-resolved diagnostics. Here, we developed a microfluidic immunosensing platform based on a rolling circle amplification-assisted DNA dendrimer probe for sensitive detection of multiple sIgEs. The versatile multichannel microfluidic whole blood analytical device integrates cell filtration, recombinant antigen-modified magnetic enrichment, and DNA dendrimer probe-amplified signal transduction for portable on-chip analysis. Three sIgEs against common oyster allergens were simultaneously detected in blood samples by simple smartphone-based imaging without any pretreatment. The quantitative detection of multiple allergen-specific antibodies on the platform was achieved with limits of detection of less than 50 pg/mL, exhibiting superior sensitivity compared to most point-of-care testing. The detection results of 55 serum samples and 4 whole blood samples were 100% consistent with the ELISA results, confirming the accuracy and stability of our platform. Additionally, the reversible combination of hexahistidine6-tag and Ni-IMAC magbead was elegantly utilized on the immunosensing platform for desired reversibility. With the advantages of general applicability, high sensitivity, and reversibility, the DNA dendrimer-based microfluidic immunosensing platform provides great potential for the portable detection of immune proteins as a point-of-care platform in disease diagnostics and biological analysis.

Management of food allergy based on oral food challenge.

Food allergy is a growing health problem that affects both patients and society in multiple ways. Despite the emergence of novel diagnostic tools, such as component-resolved diagnostics (CRD) and basophil activation tests (BAT), oral food challenge (OFC) still plays an indispensable role in the management of food allergies. This review aimed to highlight the indications and safety concerns of conducting an OFC and to provide insights into post-OFC management based on recent findings. Standardized OFC protocols have regional diversification, especially in Japan and Western countries. Recent studies suggested that the interval between doses should be at least more than an hour. Furthermore, applying a stepwise method tailored to the patient's specific immunoglobulin E level and history of anaphylaxis seems to mitigate these risks. Recent surveys have shown that, following a positive OFC, options other than strict avoidance are also selected. OFC serves diverse purposes, yet the risks it carries warrant caution. The stepwise protocol appears promising for its safety. Subthreshold consumption following OFC shows potential; however, further research on its efficacy and safety is required. Management following OFC should be tailored and well discussed between clinicians and patients.

Precision allergy molecular diagnosis applications in food allergy.

Precision medicine has become important in the diagnosis and management of food allergies. This review summarizes the latest information regarding molecular allergology, an essential component of food allergy managements. Component-resolved diagnostics (CRD) can be used to investigate sensitization to allergens based on symptoms and to reveal co-sensitization and/or cross-sensitization in patients with allergies. The following allergen components are known to be associated with symptoms: ovomucoid from eggs, omega-5 gliadin from wheat, and many storage proteins (Gly m 8 from soy, Ara h 2 from peanut, Cor a 14 from hazelnut, Ana o 3 from cashew nut, Jug r 1 from walnut, and Ses i 1 from sesame). Recent studies on allergens of macadamia nuts (Mac i 1 and Mac i 2), almonds (Pru du 6), fish (parvalbumin and collagen), and shrimp (Pem m 1 and Pem m 14) have provided additional information regarding CRD. In addition, Pru p 7 is a risk factor for systemic reactions to peaches and has recently been found to cross-react with cypress and Japanese cedar pollen. CRD provides information of individualized sensitization profiles related to symptoms and severity of allergies in patients. Clinical practice based on CRD offers many benefits, such as higher diagnostic accuracy and improved management of individual patients.

Component-specific clusters for diagnosis and prediction of allergic airway diseases.

Previous studies which applied machine learning on multiplex component-resolved diagnostics arrays identified clusters of allergen components which are biologically plausible and reflect the sources of allergenic proteins and their structural homogeneity. Sensitization to different clusters is associated with different clinical outcomes. To investigate whether within different allergen component sensitization clusters, the internal within-cluster sensitization structure, including the number of c-sIgE responses and their distinct patterns, alters the risk of clinical expression of symptoms. In a previous analysis in a population-based birth cohort, by clustering component-specific (c-s)IgEs, we derived allergen component clusters from infancy to adolescence. In the current analysis, we defined each subject's within-cluster sensitization structure which captured the total number of c-sIgE responses in each cluster and intra-cluster sensitization patterns. Associations between within-cluster sensitization patterns and clinical outcomes (asthma and rhinitis) in early-school age and adolescence were examined using logistic regression and binomial generalized additive models. Intra-cluster sensitization patterns revealed specific associations with asthma and rhinitis (both contemporaneously and longitudinally) that were previously unseen using binary sensitization to clusters. A more detailed description of the subjects' within-cluster c-sIgE responses in terms of the number of positive c-sIgEs and unique sensitization patterns added new information relevant to allergic diseases, both for diagnostic and prognostic purposes. For example, the increase in the number of within-cluster positive c-sIgEs at age 5 years was correlated with the increase in prevalence of asthma at ages 5 and 16 years, with the correlations being stronger in the prediction context (e.g. for the largest 'Broad' component cluster, contemporaneous: r = .28, p = .012; r = .22, p = .043; longitudinal: r = .36, p = .004; r = .27, p = .04). Among sensitized individuals, a more detailed description of within-cluster c-sIgE responses in terms of the number of positive c-sIgE responses and distinct sensitization patterns, adds potentially important information relevant to allergic diseases.

Use of in vitro and in vivo tests in the diagnosis of food-induced anaphylaxis – a case study

Food allergy is a chronic disease that affects both children and adults. Systemic allergic reactions in children are most commonly caused by foods, especially nuts, milk, and eggs. A conventional diagnostic work-up for allergy typically pinpoints the allergen source, while component-resolved diagnostics is an approach that identifies the allergen molecules responsible for causing anaphylaxis. In some cases, determining the causative agent of anaphylaxis requires the use of various diagnostic tests. In the following paper, we want to highlight the importance of a critical approach to allergy tests results and caution in the diagnosis of idiopathic anaphylaxis. Based on a case report of food-induced anaphylaxis, we discuss the diagnostic methods that can be applied following a negative IgE test result for allergens obtained with a multiplex platform.

Peanut Allergy and Component-Resolved Diagnostics Possibilities-What Are the Benefits?

Peanut allergy is a widespread and potentially life-threatening condition that affects both children and adults, with a growing incidence worldwide. It is estimated to affect around 1-2% of the population in several developed countries. Component-resolved diagnostics is a modern approach to allergy diagnosis that focuses on identifying specific allergenic proteins to provide precise diagnoses and personalized treatment plans. It is a technique that enables the analysis of specific IgE antibodies against tightly defined molecules (components) that constitute the allergen. Component-resolved diagnostics is particularly valuable in peanut allergy diagnosis, helping to determine allergen components associated with severe reactions. It also aids in predicting the course of the allergy and enables the development of personalized immunotherapy plans; however, the full application of it for these purposes still requires more precise studies. In this paper, we present the current knowledge about peanut allergy and component-resolved diagnostics possibilities. We discuss the possibilities of using molecular diagnostics in the diagnosis of peanut allergy. We focus on examining and predicting the development of peanut allergy, including the risk of anaphylaxis, and describe the latest data related to desensitization to peanuts.

Potential and limitations of epitope mapping and molecular targeting in Hymenoptera venom allergy.

Hymenoptera venom (HV) allergy can lead to life threatening conditions by specific IgE (sIgE)-mediated anaphylactic reactions. The knowledge about major allergens from venom of different clinically relevant species increased in the last decades, allowing the development of component-resolved diagnostics in which sIgE to single allergens is analysed. Despite these advances, the precise regions of the allergens that bind to IgE are only known for few HV allergens. The detailed characterization of IgE epitopes may provide valuable information to improve immunodiagnostic tests and to develop new therapeutic strategies using allergen-derived peptides or other targeted approaches. Epitope-resolved analysis is challenging, since the identification of conformational epitopes present in many allergens demands complex technologies for molecular analyses. Furthermore, functional analysis of the epitopeś interaction with their respective ligands is needed to distinguish epitopes that can activate the allergic immune response, from those that are recognized by irrelevant antibodies or T cell receptors from non-effector cells. In this review, we focus on the use of mapping and molecular targeting approaches for characterization of the epitopes of the major venom allergens of clinically relevant Hymenoptera species. The screening of the most relevant allergen peptides by epitope mapping could be helpful for the development of molecules that target major and immunodominant epitopes blocking the allergen induced cellular reactions as novel approach for the treatment of HV allergy.

Environmental exposure and sensitization patterns in a Swiss alpine pediatric cohort

BackgroundThe level of environmental exposure throughout life may contribute to the prevalence of allergic sensitization and allergic disease. The alpine climate has been considered a healthy climate with little allergen exposure and pollution. We conducted a cross-sectional study to investigate local environmental exposure and concomitant prevalence of allergic sensitization among local school children born and raised in an alpine environment. MethodsClinical and demographic data were collected with a questionnaire. Allergen content was assessed in residential settled dust samples, lifetime exposure to pollen and air pollution was calculated using data from national pollen and air pollution monitoring stations, and the allergic sensitization profile was determined with component resolved diagnostics (ISAC®). Univariate and multivariate regression models were used to estimate the relation between exposure and sensitization. ResultsIn a cohort of children born and raised in an alpine environment, sensitization to aeroallergens is quite common (38%), especially to grass (33%) and cat (16%). House dust mite allergen was detected in up to 38% of residential dust samples, but sensitization to HDM was low (2.5%). Pollutant levels were low, but an increasing trend was observed in the amount of ozone and PM10. Living close to a busy road was associated with increased odds OR (95% CI) for being sensitized to any allergen 2.7 (1.0–7.2), to outdoor allergens 2.8 (1.1–7.1) and being sensitized plus reporting symptoms of rhinoconjunctivitis 4.4 (1.3–14.8) and asthma 5.5 (1.4–21). Indoor living conditions, including the presence of visible mold, increased the odds of being sensitized to indoor allergens (1.9 (1.1–3.2) and being sensitized plus reporting symptoms of rhinoconjunctivitis 1.9 (1.0–3.6) and asthma 2.1 (1.0–4.1). ConclusionIn a healthy alpine environment, pollution might still be an important factor contributing to allergic sensitization.

Basophil activation test (BAT) in double-sensitized patients with Hymenoptera venom allergy: additional benefit of component-resolved diagnostics.

In Hymenoptera venom allergy serologically double-sensitized patients it is often difficult to identify the culprit insect for venom immunotherapy (VIT). To evaluate if basophil activation tests (BATs) performed not only with venom extracts but additionally with single component-resolved diagnostics could differentiate between sensitized and allergic individuals and how the test results influenced the physicians' decision regarding VIT. BATs were performed with bee and wasp venom extracts and with single components (Api m 1, Api m 10, Ves v 1, Ves v 5) in 31 serologically double-sensitized patients. In 28 finally included individuals 9 BATs were positive and 4 negative for both venoms. 14/28 BATs showed positive results for wasp venom alone. 2/10 BATs positive for bee venom were only positive to Api m 1 and 1/28 BAT only to Api m 10, but not for whole bee venom extract. 5/23 BATs positive for wasp venom were only positive for Ves v 5, but negative for wasp venom extract and Ves v 1. Finally, VIT with both insect venoms was recommended in 4/28 individuals, with wasp venom alone in 21/28 patients and with bee venom alone in 1/28. In 2 cases no VIT was recommended. BATs with Ves v 5, followed by Api m 1 and Api m 10, were helpful for the decision for VIT with the clinically relevant insect in 8/28 (28.6%) patients. A BAT with components should therefore be additionally carried out in cases with equivocal results.

Identification of allergens in Artocarpus heterophyllus, Moringa oleifera, Trianthema portulacastrum and Syzygium samarangense

BackgroundIt is clinically important to identify allergens in Artocarpus heterophyllus (jackfruit), Moringa oleifera (moringa), Trianthema portulacastrum (horse purslane) and Syzygium samarangense (rose apple). This study included 7 patients who developed anaphylaxis to jackfruit (1), moringa (2), horse purslane (3) and rose apple (1). We sought to determine allergens in the edible ripening stages of jackfruit (tender, mature, and ripened jackfruit) and seeds, edible parts of moringa (seeds, seedpod, flesh inside seedpod, and leaves), horse purslane leaves and ripened rose apple fruit. The persistence of the allergens after cooking was also investigated.MethodsAllergens were identified by clinical history followed by a skin prick test. Protein profiles of plant/fruit crude protein extracts were determined by SDS-PAGE. Molecular weights of the allergens were determined by immunoblotting with patient sera.ResultsA heat-stable allergen of 114 kDa in A. heterophyllus which is shared among different ripening stages and seeds was identified. Additionally, 101 kDa allergen in boiled tender jackfruit, 86 kDa allergen in boiled seeds and 80 kDa allergen in boiled mature jackfruit were identified. Five heat-stable allergens of 14, 23, 35, 43, and 48 kDa in M. oleifera, 1 heat-stable allergen of 97 kDa in T. portulacastrum, and 4 allergens of 26, 31. 60, and 82 kDa in S. samarangense were identified.ConclusionNovel IgE-sensitive proteins of A. heterophyllus, M. oleifera, T. portulacastrum and S. samarangense were identified which would be especially useful in the diagnosis of food allergies. The identified allergens can be used in Component Resolved Diagnostics (CRD).

Component-resolved Diagnostics in Allergy Practice Focusing on Food Allergy: A Systematic Review

Component-resolved Diagnostics in Allergy Practice Focusing on Food Allergy: A Systematic Review

The role of basophil activation test and component-resolved diagnostics in the workup of egg allergy in children at low risk for severe allergic reactions: A real-life study.

The gold standard for diagnosing egg allergy in children is the oral food challenge (OFC). However, OFCs are time-consuming and risky procedures. Our study aimed to evaluate the utility of the basophil activation test (BAT) and component-resolved diagnostic in the diagnostic workup of children with egg allergy. Overall, 86 children aged 6 months to 17 years, suspected of egg allergy, underwent OFC with boiled egg according to international standardized protocols. BAT and specific immunoglobulin E (sIgE) testing to component egg proteins (Gal d 1-4) were also performed. Of the 22 children who reacted to boiled egg, only one experienced anaphylaxis during the challenge. BAT was performed in samples obtained by 75 of the 86 patients of our cohort. Egg white and yolk protein extracts induced CD63 upregulation in the egg-allergic (EA) children compared with sensitized children that tolerated boiled egg (we registered an overall mean of CD63 expression in the EA population of 44.4% [SD 34.1] for egg white and 34.7% [SD 31.3] for egg yolk vs. 12.5% [SD 19.1] and 10.0% [SD 16.0] in sensitized children). BAT could discriminate between true egg allergy and egg sensitization in our population. As a second-line diagnostic step, the positivity of BAT for egg white or Gal d 1-sIgE resulted in a 40.9% OFC reduction, especially for those with a positive outcome. The BAT may be implemented in the diagnostic workup of egg allergy in children and, in a stepwise approach, separately or combined with Gal d 1-sIgE, may predict the allergic status and reduce the number of positive OFCs in children with egg allergy at low risk for severe reactions.

Sensitization patterns to Poaceae pollen indicates a hierarchy in allergens and a lead of tropical grasses.

The allergenicity of pollen of Poaceae family members is a well-known and confirmed fact. Using the data of component-resolved molecular diagnostics of allergy, we set a goal to establish the population and individual characteristics of sensitization to grass pollen and assess the patterns of its development. Multiplex allergy Alex2 test results of 20,033 patients were used. In addition to descriptive statistics to uncover traits of the sensitized population, statistical inference was utilized to establish the conditional probability of sensitisation, the nature of links between allergens, and the most frequent combinations of allergens in individual patient profiles. Sensitivity to grass pollen comprised 30.79% of the studied sample. Children accounted for 62.21%, adults-37.79%. Sensitisation to Phl p 1, Lol p 1, and Cyn d 1 was the most frequent in all age groups. Among them, Phl p 1 and Lol p 1 were the major ones. Phl p 2, Phl p 5.0101, and Phl p 6 were also responsible for primary sensitization; Phl p 5.0101 promoted the highest sIgE levels. A combination "Lol p 1-Phl p 1", where Lol p 1 might play a leading role, was most frequent in individual profiles. Monosensitization to Phl p 2 was the second most frequent and Bayesian Network suggested its independent development. Monosensitization to Cyn d 1, especially among children, may indicate the impact of climate change, promoting the spread of the subtropical grasses to the temperate region. Descriptive statistics and known clinical data coincide well with statistical inference results and can provide for new clinical insights.

Tropomyosins of the helminthes: Sensitization and association with allergic diseases

The increase in the prevalence of allergic diseases has been a driver of the development of new technologies. Over the past two decades, significant progress in biochemistry and molecular allergology has contributed to the study of the structure of allergens and development of component-resolved diagnostics. Specifically, clinically significant families of allergens have been identified, including tropomyosin, which can cause various cross-IgE-mediated reactions. One of the risk factors for sensitization development is helminthiasis, which is common in different regions and population of endemic areas. The global prevalence of helminthiasis remains high. Approximately 1.5 billion people worldwide have chronic infections with at least one helminth.
 This review aimed to analyze current studies determining the relationship between helminth infections and the development of sensitization to helminth tropomyosin and clinical course of allergic diseases.
 The analysis of scientific publications described the relationship between helminth tropomyosin and the development of allergic diseases and sensitization in patients with parasitic infection. The PubMed database was used for the review. The review included original articles published between January 1, 2000, and December 31, 2021.

Ni-NTA resin-based multiplexed origami device for highly efficient sensing of allergen-specific IgE

Food allergy diagnosis requires a highly sensitive detection of allergen-specific immunoglobulin E (sIgE) in the serum. Enzyme-linked immunosorbent assay (ELISA) is a classical method widely used for sIgE detection but had to rely on costly and time-consuming assay procedures, skilled technicians, and bulky equipment. Here, a multiplexed origami paper analytical device (moPAD) that is hexahistidine-tagged and integrated with a nitrilotriacetic acid-functionalized surface with nickel (Ni-NTA) was developed to achieve low-cost and high-efficiency immunosensing of multiple allergen-specific IgEs in serum. The major oyster allergens, Cra a 1, Cra a 2, and Cra a 4, were used to detect sIgE in human serum. The feasibility of the moPAD-based immunosensing strategy was successfully demonstrated by desirable sensitivities for multiple targets. The detection results of moPAD for 72 serum samples were 100% consistent with clinical test results, while 69 of these results showed no significant differences from ELISA results, demonstrating the accuracy and stability of this method. A fully integrated moPAD reduces detection time and achieves highly sensitive quantification using a simple smartphone-based readout. Efficient allergen modification of paper devices has great applicability in allergen component-resolved diagnostics. The implementation of moPAD can make the process of allergy diagnosis simpler for patients, physicians, and healthcare systems alike.

Molecular diagnostics and inhibition of cross-reactive carbohydrate determinants in Hymenoptera venom allergy.

The composition of venom extracts, cross-reactive carbohydrate determinants (CCD) and the component-resolved diagnostics (CRD) are important fields of investigation. IgE-reactivity to CCD complicates the interpretation of IgE to Hymenoptera venoms, especially in patients with multiple-positivity. We analyzed the clinical importance of CRD and CCD-inhibition for selection of allergens for venom immunotherapy (VIT). In 71 patients, we measured specific IgE (sIgE) to honeybee venom (HBV), wasp venom (WV), hornet venom (HV), CCD, and recombinant allergens: phospholipase A2 (rApi m 1), hyaluronidase (rApi m 2), icarapin (rApi m 10), antigen 5 (rVes v 5), and phospholipase A1 (Immunoblot). In 29/71 HBV/WV/HV/CCD-positive patients CCD-inhibition was performed. According to CRD and CCD-inhibition, we identified true sensitization and defined groups of multiple-positive patients who needed CCD-inhibition before starting VIT. sIgE-rApi m 1, sIgE-rApi m 2, and sIgE-rApi m 10 were detected in 65.7%, 68.4%, and 58%, respectively. In HBV allergic patients, CRD sensitivity was 86.8%. In WV allergic patients, sensitivity of sIgE-rVes v 5 was 94%. True multiple-sensitization was found in 44.8% of HBV/WV/HV/CCD-positive patients after CCD-inhibition. Patients with multiple venom- and CCD-positivity had more frequent severe allergic reactions (p<0.001). CCD-inhibition was helpful in HBV/WV/HV/CCD-positive patients who were negative to all tested recombinant honeybee allergens. Persistence of HBV-positivity after CCD-inhibition requires CRD to other honeybee recombinant allergens. CRD, using a profile of five most important recombinant allergens and CCD, has a high sensitivity for the diagnosis of venom allergy, especially in patients positive to several venom extracts. CRD and CCD-inhibition are helpful to reveal the clinically relevant, true sensitization and improve the selection of venoms for long-lasting VIT.

Molecular Aspects of Allergen-Specific Immunotherapy in Patients with Seasonal Allergic Rhinitis.

A systematic review and narrative synthesis of publications was undertaken to analyze the role of component-resolved diagnosis technology in identifying polysensitization for the provision of allergen-specific immunotherapy to patients with seasonal allergic rhinitis. A search of publications was carried out in electronic databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The search helped to identify 568 publications, 12 of which were included in this review. Overall, 3302 patients were enrolled. The major finding was that component-resolved diagnostics change the choice of relevant allergens for allergen-specific immunotherapy in at least 50% of cases. Sensitization to allergen components differs with age, type of disease, and overall disease duration. Patients who had both bronchial asthma and allergic rhinitis were sensitized to a larger number of allergens than patients who had bronchial asthma alone.

The significance of component-resolved allergy diagnostics in atopic dermatitis patients when prescribing allergen-specific immunotherapy

The paper presents clinical cases of patients with severe atopic dermatitis with polyvalent sensitization in an adult patient and in a pediatric patient. Standard topical and systemic therapy proved to be an insufficiently effective strategy in these patients. Both patients underwent component-resolved allergy diagnostics, which made it possible to identify the causally significant components of allergens, sensitization to which affects the course of atopic dermatitis. On the basis of the survey, indications for allergen-specific immunotherapy with causally significant allergens were determined. The treatment made it possible to achieve non-drug remission not only of atopic dermatitis but also of concomitant respiratory allergic diseases.&#x0D; The cases demonstrate the efficacy and safety of allergen-specific immunotherapy in patients with proven sensitization to causally significant allergens based on component allergy diagnostics.