A new automated multiple allergen simultaneous test-chemiluminescent assay (MAST-CLA) using an AP720S analyzer

Metabolomics reveals microbial-derived metabolites associated with immunoglobulin E responses in filaggrin-related atopic dermatitis

BACKGROUND

Filaggrin (FLG) gene mutation and immunoglobulin E (IgE)-mediated sensitization are the most important predictors of atopic dermatitis (AD). However, a metabolomics-based approach to address the metabolic impact of FLG mutations on allergic IgE responses for AD is still lacking. We, though, determine the relationships of metabolic profiles in AD with FLG mutations and allergic responses.

METHODS

Eighty-one children with adolescent AD (n = 58) and healthy controls (n = 23) were prospectively enrolled. Mutations in the filaggrin gene were identified using whole-exome sequencing, and plasma metabolic profiles were determined using ¹ H-nuclear magnetic resonance (NMR) spectroscopy. Integrative analyses of their associations related to total serum IgE levels were performed, and further metabolic functional pathways for AD were also assessed.

RESULTS

Metabolites contributed to the separation between AD and controls were identified using the supervised partial least squares discriminant analysis (Q² /R²  = 0.90, P_permutation <0.001). Nitrogen and amino acid metabolisms for energy production, and microbe-related methane and propanoate metabolisms were significantly associated with AD compared with healthy controls (FDR-adjusted p < .05). Five of fifteen metabolites related to FLG mutations were positively correlated with total serum IgE levels. Among them, dimethylamine and isopropanol were strongly associated with methane metabolism and propanoate metabolism, respectively, in AD with FLG mutations (FDR-adjusted p < .01).

CONCLUSION

A strong correlation of microbial-derived metabolites, dimethylamine and isopropanol, with FLG mutations and IgE allergic reactions provides the influence of host genetics on the microbiome to regulate susceptibility to allergic responses in the pathogenesis of AD.

IgE allergy diagnostics and other relevant tests in allergy, a World Allergy Organization position paper

Currently, testing for immunoglobulin E (IgE) sensitization is the cornerstone of diagnostic evaluation in suspected allergic conditions. This review provides a thorough and updated critical appraisal of the most frequently used diagnostic tests, both in vivo and in vitro. It discusses skin tests, challenges, and serological and cellular in vitro tests, and provides an overview of indications, advantages and disadvantages of each in conditions such as respiratory, food, venom, drug, and occupational allergy. Skin prick testing remains the first line approach in most instances; the added value of serum specific IgE to whole allergen extracts or components, as well as the role of basophil activation tests, is evaluated. Unproven, non-validated, diagnostic tests are also discussed. Throughout the review, the reader must bear in mind the relevance of differentiating between sensitization and allergy; the latter entails not only allergic sensitization, but also clinically relevant symptoms triggered by the culprit allergen.

Evaluation of AdvanSure AlloScreen Max Panel With 92 Different Allergens for Detecting Allergen-Specific IgE

OBJECTIVES

The objective of this study was to examine the performance of AdvanSure AlloScreen Max with 92 different allergens compared to Polycheck Allergy and ImmunoCAP. The relationship of serum IgE concentration with the number and the highest class/level of positive allergen-specific IgEs was also examined.

METHODS

A total of 406 serum samples were included in this study. Discrepant cases between AdvanSure AlloScreen Max and Polycheck Allergy underwent ImmunoCAP testing for allergen-specific IgE.

RESULTS

Total agreement of the two multiple allergen simultaneous tests (MAST) was 92.5%. Compared to ImmunoCAP, total agreement rate was higher with AdvanSure AlloScreen Max (60.8%) than that with Polycheck Allergy (39.2%). Serum IgE concentration showed a significant and positive correlation with the number and the highest class/level of positive allergen-specific IgEs.

CONCLUSIONS

A MAST assay panel containing as many allergens as possible would be more helpful in the allergen screening for patients with high serum IgE concentration.

Dry eye disease and allergic conditions: A Korean nationwide population-based study

BACKGROUND

Dry eye disease (DED) is a multifactorial disease of the tears and ocular surface. No epidemiologic reports have yet been published about the relationship between DED and allergic rhinitis or sensitization to allergens.

OBJECTIVE

To investigate the association between DED and allergic conditions in the general adult Korean population.

METHODS

This population-based cross-sectional study included 17,542 individuals (ages ≥ 19 years) who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2010 to 2012. Data for total serum immunoglobulin E (IgE) and allergen-specific IgE levels were available for 1857 subjects. Data were analyzed by using logistic regression to determine the association of DED with allergy or allergic conditions, including allergic rhinitis, atopic dermatitis, asthma, increased total serum IgE, and sensitization to house-dust mite (Dermatophagoides farinae), dog, and cockroach allergens.

RESULTS

The prevalence of DED, allergic rhinitis, atopic dermatitis, and asthma was 10.4, 13.1, 2.2, and 3.3%, respectively. The prevalence of the increased total serum IgE level and sensitization to D. farinae, dog, and cockroach allergens was 34.6, 15.7, 1.0, and 2.8%, respectively. After adjusting for general characteristics, DED was significantly associated with allergic rhinitis (odds ratio 1.58 [95% confidence interval, 1.38-1.81]) and D. farinae sensitization (odds ratio 1.80 [95% confidence interval, 1.17-2.79]).

CONCLUSION

This study demonstrated a close association between DED and both allergic rhinitis and D. farinae sensitization in Korean adults. Further studies are warranted to establish temporal relationships between DED and allergic rhinitis.

Application of immuno-PCR assay for the detection of serum IgE specific to Bermuda allergen

In vivo and in vitro tests are the two major ways of identifying the triggering allergens in sensitized individuals with allergic symptoms. Both methods are equally significant in terms of sensitivity and specificity. However, in certain circumstances, in vitro methods are highly preferred because they circumvent the use of sensitizing drugs in patients. In current study, we described a highly sensitive immuno-PCR (iPCR) assay for serum IgE specific to Bermuda allergens. Using oligonucleotide-labelled antibody, we used iPCR for the sensitive detection of serum IgE. The nucleotide sequence was amplified using conventional PCR and the bands were visualized on 2.5% agarose gel. Results demonstrated a 100-fold enhancement in sensitivity of iPCR over commercially available enzyme-linked immunosorbent assay (ELISA) kit. Our iPCR method was highly sensitive for Bermuda-specific serum IgE and could be beneficial in allergy clinics.

Food Allergy in Korean Patients with Chronic Urticaria

Background

The etiology of chronic urticaria (CU) remains unknown in most patients. Possible causes in some cases include food, but the role of allergy to food antigens in patients with CU remains controversial.

Objective

The aim of this study was to evaluate the association between food allergy and CU.

Methods

Korean patients with CU were assessed for a previous history of food allergy that caused symptoms of CU. Blood samples were taken from 350 patients to measure food allergen-specific IgE. Based on history and laboratory results, open oral food challenge (OFC) tests were performed.

Results

Of 350 participants, 46 (13.1%) claimed to have experienced previous food hypersensitivity. Pork (n=16) was the main food mentioned, followed by beef (n=7), shrimp (n=6), and mackerel (n=6). We found that 73 participants (20.9%) had elevated levels of food-specific IgE, with pork (n=30), wheat (n=25), and beef (n=23) being the most common. However, when the open OFC tests were conducted in 102 participants with self-reported food hypersensitivity or raised levels of food-specific IgE, only four participants showed a positive reaction to pork (n=3) or crab (n=1).

Conclusion

Although some participants claimed to have a history of CU related to food intake, when an open OFC test was conducted, few of them had positive results. We therefore conclude that food allergy is an uncommon cause of chronic CU.

Comparison and clinical utility evaluation of four multiple allergen simultaneous tests including two newly introduced fully automated analyzers

Background

We compared the diagnostic performances of two newly introduced fully automated multiple allergen simultaneous tests (MAST) analyzers with two conventional MAST assays.

Methods

The serum samples from a total of 53 and 104 patients were tested for food panels and inhalant panels, respectively, in four analyzers including AdvanSure AlloScreen (LG Life Science, Korea), AdvanSure Allostation Smart II (LG Life Science), PROTIA Allergy-Q (ProteomeTech, Korea), and RIDA Allergy Screen (R-Biopharm, Germany). We compared not only the total agreement percentages but also positive propensities among four analyzers.

Results

Evaluation of AdvanSure Allostation Smart II as upgraded version of AdvanSure AlloScreen revealed good concordance with total agreement percentages of 93.0% and 92.2% in food and inhalant panel, respectively. Comparisons of AdvanSure Allostation Smart II or PROTIA Allergy-Q with RIDA Allergy Screen also showed good concordance performance with positive propensities of two new analyzers for common allergens (Dermatophagoides farina and Dermatophagoides pteronyssinus). The changes of cut-off level resulted in various total agreement percentage fluctuations among allergens by different analyzers, although current cut-off level of class 2 appeared to be generally suitable.

Conclusions

AdvanSure Allostation Smart II and PROTIA Allergy-Q presented favorable agreement performances with RIDA Allergy Screen, although positive propensities were noticed in common allergens.

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Two new multiple allergen simultaneous tests (MAST) analyzers are evaluated.

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AdvanSure Smart II and PROTIA presented favorable agreement performance with RIDA.

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Positive propensity of new assays for D. farina and D. pteronyssinus was noticed.

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The changes of cut-off level resulted in total agreement percentage fluctuations.

Performance of the PROTIA™ Allergy-Q® System in the Detection of Allergen-specific IgE: A Comparison With the ImmunoCAP® System

PURPOSE

The PROTIA™ Allergy-Q® enzyme immunoassay (EIA) is a recently developed screening assay for specific immunoglobulin E (sIgE) for multiple allergens. The ImmunoCAP® fluorescent EIA (FEIA) system is the most widely used method for sIgE detection. In this study, we evaluated the performance of the Allergy-Q® system compared to the ImmunoCAP® system.

METHODS

We compared the 2 systems using sera from 260 Korean allergy patients suffering from asthma (26.5%), allergic rhinitis (42.3%), atopic dermatitis (67.7%), and food allergy (18.1%). We compared sIgE-measurement results for 7 inhalant allergens, 5 food allergens, and 4 microorganism allergens.

RESULTS

Overall, 1,799 paired assay results were analyzed. Except mugwort and alternaria, most of the allergen-sIgE results showed intra-class correlation coefficients of >0.5. Inter-assay class associations were reliable for most allergens (gamma=0.858-0.987, P<0.001). Passing-Bablok regression analysis showed multiple differences in intercept and slope. The inter-method concordance was moderate to substantial for most allergens (κ=0.713-0.898, P<0.001).

CONCLUSIONS

The PROTIA™ Allergy-Q® EIA system exhibited good detection performance compared to the ImmunoCAP® FEIA system in Korean allergic patients. However, because of methodological differences between the 2 assays, careful clinical implication is required for the interpretation of Allergy-Q® EIA results.

Tus-Ter-lock immuno-PCR assays for the sensitive detection of tropomyosin-specific IgE antibodies

BACKGROUND

The increasing prevalence of food allergies requires development of specific and sensitive tests capable of identifying the allergen responsible for the disease. The development of serologic tests that can detect specific IgE antibodies to allergenic proteins would, therefore, be highly received.

RESULTS

Here we present two new quantitative immuno-PCR assays for the sensitive detection of antibodies specific to the shrimp allergen tropomyosin. Both assays are based on the self-assembling Tus-Ter-lock protein-DNA conjugation system. Significantly elevated levels of tropomyosin-specific IgE were detected in sera from patients allergic to shrimp.

CONCLUSION

This is the first time an allergenic protein has been fused with Tus to enable specific IgE antibody detection in human sera by quantitative immuno-PCR.

Comparison of three multiple allergen simultaneous tests: RIDA allergy screen, MAST optigen, and polycheck allergy

We compared the performances of 3 Multiple Allergen Simultaneous Test (MAST) assays: RIDA Allergy Screen (R-Biopharm, Darmstadt, Germany), MAST Optigen allergy system (Hitachi Chemical Diagnostics, Mountain View, CA), and Polycheck Allergy (Biocheck GmbH, Munster, Germany). Forty sera that tested positive with the RIDA Allergy Screen (20 for food and 20 for inhalant panel) were subjected to MAST Optigen and Polycheck Allergy. For 26 available sera with discrepant results, 62 ImmunoCAP allergen-specific IgE tests (Pharmacia Diagnostics, Uppsala, Sweden) were performed. Percent agreements (kappa value) were 87.6% (0.59) and 91.3% (0.60) between RIDA and MAST; 89.9% (0.55) and 88.3% (0.46) between RIDA and Polycheck; and 86.8% (0.51) and 90.6% (0.61) between MAST and Polycheck. Compared with ImmunoCAP, agreements (kappa value) of inhalant and food panels were 51.7% (0.04) and 33.3% (−0.38) for RIDA; 60.7% (0.27) and 81.8% (0.59) for MAST; and 65.5% (0.26) and 45.5% (0.07) for Polycheck. The agreements between RIDA, MAST, and Polycheck and ImmunoCAP-positivity were 45.7%, 88.2%, and 28.6%, respectively, and the agreements for ImmunoCAP-negativity were 37.0%, 51.9%, and 88.9%. MAST Optigen showed better agreement with ImmunoCAP than other assays in the food panel. Better sensitivity of MAST Optigen and better specificity of Polycheck Allergy were suspected.

Specific IgE measurement using AdvanSure® system: comparison of detection performance with ImmunoCAP® system in Korean allergy patients

BACKGROUND

AdvanSure enzyme immunoassay (EIA) system is a recently developed multiple allergen screen test with specific immunoglobulin E (sIgE) detection assay, while ImmunoCAP fluorescent EIA (FEIA) has been widely used for sIgE detection. There has been no inter-assay comparison data for these two systems. We determined the detection performance of AdvanSure system compared to that of ImmunoCAP.

METHODS

We performed an inter-method comparison using sera from 199 Korean allergy patients, including asthma (39.7%), allergic rhinitis (54.8%), atopic dermatitis (36.2%) and food allergies (21.6%). We compared the sIgE detection performance for nine major inhalant and four food allergens.

RESULTS

950 paired assay results were analyzed. Most allergen sIgE results showed above 0.5 intraclass correlation coefficient except Blattella germanica, alternaria and mugwort allergen. Intermethod comparison results showed multiple differences in a few allergens. The inter-method concordance was moderate to substantial for most allergens (κ=0.528-0.778, p<0.001), except for cat dander.

CONCLUSION

AdvanSure system showed a good detection performance compared with ImmunoCAP in correlation and agreement in Korean allergy patients. However, in terms of differences in the methodologies used by these two systems, careful clinical correlation is needed for interpretation of AdvanSure EIA results.

[Usefulness of total IgE in predicting positive allergen specific IgE Tests in Korean subjects]

BACKGROUND

Total IgE levels in allergic patients tend to be higher than those in healthy individuals. We evaluated the usefulness of total IgE levels in predicting positive results of allergen specific IgEs in multiple allergen simultaneous tests.

METHODS

A total of 133 patients with allergic symptoms were evaluated. Allergen specific IgEs were detected using 3 different kits: Allergy screen (R-biopharm, Germany), AdvanSure Allergy Screen (LG Life Science, Korea) and Polycheck allergy (Biocheck Co., Germany). Total IgE was measured by turbidoimmunometric assay (LX-2200, Eiken Chemical Co., Japan). The patients were divided into high (≥ 170 IU/mL) and low (<170 IU/mL) groups of total IgE level, and the positive rates and number of positive allergen specific IgEs were evaluated in each group. Positive concordance rates among different kits were also evaluated.

RESULTS

High total IgE group showed significantly higher positive rates and number of positive allergen specific IgEs in all of the 3 test kits used compared to low total IgE group. Only two of the allergens, Dermatophagoides farinae and Dermatophagoides pteronyssinus had positive concordance rates of ≥ 50%. Allergen specific IgEs to these two allergens showed good correlation with total IgE (correlation coefficients >0.5).

CONCLUSIONS

Total IgE appears to be useful in predicting positive results in allergen specific IgE tests to common allergens. The specific IgEs to D. farinae and D. pteronyssinus showed good correlation with total IgE. However, for other allergens, significant differences were observed among different test kits, and the standardization of allergens in multiple allergen simultaneous tests is needed.

Microarrayed allergen molecules for the diagnosis of allergic diseases

IgE-mediated allergic diseases are among the most prevalent diseases worldwide. The use of extracts in the skin test and the additional use of IgE testing still represent the current basis for the diagnostic work-up. During the past 30 years, knowledge of the molecular structure of allergens has increased dramatically, and the characterization and production of allergenic molecules, as natural purified compounds or recombinant products, is allowing us to approach the allergy diagnostic work-up differently. Much of this is based on the adoption of microtechnology since the first release of a biochip for IgE detection. Its use has prompted the development of new concepts linked to the diagnosis of allergic diseases. This review describes the background of allergy diagnosis and the tools currently used for specific IgE detection. It gives insight into the most recent advancement in the field of biotechnology leading to allergenic molecule availability, microtechnology leading to the routine use of protein biochips for IgE detection, and how they should be combined with information technology.