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Background: Current in vitro allergen‐specific IgE (sIgE) detection assays measure IgE against allergen extracts or molecules in a single‐ or multiplex approach. Direct comparisons of the performance of such assays among young children with common presentations of allergic diseases regardless of sensitization status are largely missing. Objectives: The aim of this study was a comparison of the analytical and diagnostic performance for common clinical questions of three commonly used technologies which rely upon different laboratory methodologies among children of the All Age Asthma (ALLIANCE) cohort (clinicaltrials.gov: NCT02496468). Methods: Sera from 106 paediatric study participants (mean age 4 years) were assessed for the presence of sIgE by means of the ImmunoCAP™ sx1 and fx5 mixes, the ImmunoCAP ISAC™ 112 microarray and a Euroline™ panel. Results: Total and negative concordance was high (>82%–>89%), while positive concordance varied considerably (0%–100%) but was also >50% for the most common sensitizations analysed (house dust mite and birch). All three test systems showed good sensitivity and specificity (AUC consistently > 0.7). However, no significant differences with regard to identifying sIgE sensitizations associated with symptoms in children with suspected pollen‐ or dust‐triggered wheeze or presenting with symptoms of allergic rhinoconjunctivitis or food allergy were detected. Extending the number of allergens did not change the similar performance of the three assay systems. Conclusion and Clinical Relevance: Among young children, the three sIgE assays showed good analytical and diagnostic concordance. Our results caution that the identification of larger numbers of sensitizations by more comprehensive multiplex approaches may not improve the clinical utility of sIgE testing in this age group. [ABSTRACT FROM AUTHOR]

Respiratory virus infections play a major role in asthma, while there is a close correlation between asthma and food allergy. We hypothesized that T cell-mediated heterologous immunity may induce asthma symptoms among sensitized individuals and used two independent in silico pipelines for the identification of cross-reactive virus- and food allergen- derived T cell epitopes, considering individual peptide sequence similarity, MHC binding affinity and immunogenicity. We assessed the proteomes of human rhinovirus (RV1b), respiratory syncytial virus (RSVA2) and influenza-strains contained in the seasonal quadrivalent influenza vaccine 2019/2020 (QIV 2019/2020), as well as SARS-CoV-2 for human HLA alleles, in addition to more than 200 most common food allergen protein sequences. All resulting allergen-derived peptide candidates were subjected to an elaborate scoring system considering multiple criteria, including clinical relevance. In both bioinformatics approaches, we found that shortlisted peptide pairs that are potentially binding to MHC class II molecules scored up to 10 × lower compared to MHC class I candidate epitopes. For MHC class I food allergen epitopes, several potentially cross-reactive peptides from shrimp, kiwi, apple, soybean and chicken were identified. The shortlisted set of peptide pairs may be implicated in heterologous immune responses and translated to peptide immunization strategies with immunomodulatory properties. [ABSTRACT FROM AUTHOR]

Background: After the re-introduction of ImmunoCAP® ISAC sIgE 112 on the market, we undertook a study to evaluate the performance of this multiplex-based immunoassay for IgE measurements to allergen components. Methods: The study was carried out at 22 European and one South African site. Microarrays from different batches, eight specific IgE (sIgE) positive, three sIgE negative serum samples and a calibration sample were sent to participating laboratories where assays were performed according to the manufacturer's instructions. Results: For both the negative and positive samples results were consistent between sites, with a very low frequency of false positive results (0.014%). A similar pattern of results for each of the samples was observed across the 23 sites. Homogeneity analysis of all measurements for each sample were well clustered, indicating good reproducibility; unsupervised hierarchical clustering and classification via random forests, showed clustering of identical samples independent of the assay site. Analysis of raw continuous data confirmed the good accuracy across the study sites; averaged standardized, site-specific ISU-E values fell close to the center of the distribution of measurements from all sites. After outlier filtering, variability across the whole study was estimated at 25.5%, with values of 22%, 27.1% and 22.4% for the 'Low', 'Moderate to High' and 'Very High' concentration categories, respectively. Conclusions: The study shows a robust performance of the ImmunoCAP® ISAC 112 immunoassay at different sites. Essentially the same results were obtained irrespective of assay site, laboratory-specific conditions and instruments, operator, or the use of microarrays from different batches. [ABSTRACT FROM AUTHOR]

The outbreak of the new severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is a public health emergency. Asthma does not represent a risk factor for COVID-19 in several published cohorts. We hypothesized that the SARS-CoV-2 proteome contains T cell epitopes, which are potentially cross-reactive to allergen epitopes. We aimed at identifying homologous peptide sequences by means of two distinct complementary bioinformatics approaches. Pipeline 1 included prediction of MHC Class I and Class II epitopes contained in the SARS-CoV-2 proteome and allergens along with alignment and elaborate ranking approaches. Pipeline 2 involved alignment of SARS-CoV-2 overlapping peptides with known allergen-derived T cell epitopes. Our results indicate a large number of MHC Class I epitope pairs including known as well as de novo predicted allergen T cell epitopes with high probability for cross-reactivity. Allergen sources, such as Aspergillus fumigatus, Phleum pratense and Dermatophagoides species are of particular interest due to their association with multiple cross-reactive candidate peptides, independently of the applied bioinformatic approach. In contrast, peptides derived from food allergens, as well as MHC class II epitopes did not achieve high in silico ranking and were therefore not further investigated. Our findings warrant further experimental confirmation along with examination of the functional importance of such cross-reactive responses. [ABSTRACT FROM AUTHOR]

Objectives: Detection of allergen-specific immunoglobulin E (sIgE) is important for the diagnosis of allergy. IgE sensitization is commonly demonstrated in vivo by skin prick testing (SPT), or in vitro utilizing automated systems. Recently, HYCOR® Biomedical launched its new system for allergen sIgE testing called the NOVEOS™ Immunoanalyzer. This study aims to evaluate the analytical performance of the NOVEOS system in a bi-center study at Philipps-University Marburg (Site-1) and Charité Medical University Berlin (Site-2), respectively. Methods: The analytical performance was evaluated based on the guidelines I/LA20-A3, EP5-A3, EP17-A2, EP6-A, EP7-A3, and EP9-A3 of the Clinical and Laboratory Standards Institute (CLSI). Results: The conducted repeatability and within-laboratory precision tests provided acceptable performance with 3.0%–11.9% coefficient of variation across both sites. The limit of blank (LoB) and limit of detection (LoD) were <0.1 kU/L at both centers. A within-parameter linearity for all tested allergens was reported at both sites. Of note, no significant interference was observed for high levels of biotin, methylprednisolone, diphenhydramine, omalizumab, or ranitidine. Method comparison between the NOVEOS calibration and the latest World Health Organization (WHO) reference standard showed good agreement at both sites. Conclusions: The results from the analytical performance of the NOVEOS allergen sIgE assay and instrument testing at both sites were comparable. Overall, a good precision and linearity as well as a detection limit <0.1 kU/L were observed, with minimal impact of common interfering substances on patient recoveries. The NOVEOS is calibrated to the latest WHO reference standard and adds benefits like a small sample size and para-magnetic microparticles that improve upon third-generation allergen sIgE assays' design and performance. [ABSTRACT FROM AUTHOR]

Correct identification of the culprit allergen is an essential part of diagnosis and treatment in immunoglobulin E (IgE)-mediated allergic diseases. In recent years, molecular biology has made important advances facilitating such identification and overcoming some of the drawbacks of natural allergen extracts, which consist of mixtures of various proteins that may be allergenic or not, specific for the allergen source or widely distributed (panallergens). New technologies offer the opportunity for a more accurate component-resolved diagnosis, of benefit especially to polysensitized allergic patients. The basic elements of molecular diagnostics with potential relevance to immunotherapy prescription are reviewed here, with a focus on Southern European sensitization patterns to pollen allergens. We propose a basic algorithm regarding component-resolved diagnostic work-up for pollen allergen-specific immunotherapy candidates in Southern Europe; this and similar algorithms can form the basis of improved patient management, conceptually a 'Component-Resolved Allergy Management'. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]