Identification and characterization of an α-1,3 mannosidase from Elizabethkingia meningoseptica and its potential attenuation impact on allergy associated with cross-reactive carbohydrate determinant.

Core α-1,3 mannose is structurally near the core xylose and core fucose on core pentasaccharide from plant and insect glycoproteins. Mannosidase is a useful tool for characterization the role of core α-1,3 mannose in the composition of glycan related epitope, especially for those epitopes in which core xylose and core fucose are involved. Through functional genomic analysis, we identified a glycoprotein α-1,3 mannosidase and named it MA3. We used MA3 to treat allergen horseradish peroxidase (HRP) and phospholipase A2 (PLA2) separately. The results showed that after MA3 removed α-1,3 mannose on HRP, the reactivity of HRP with anti-core xylose polyclonal antibody almost disappeared. And the reactivity of MA3-treated PLA2 with anti-core fucose polyclonal antibody decreased partially. In addition, when PLA2 was conducted enzyme digestion by MA3, the reactivity between PLA2 and allergic patients' sera diminished. These results demonstrated that α-1,3 mannose was an critical component of glycan related epitope.

Relationship between IgE Levels Specific for Ragweed Pollen Extract, Amb a 1 and Cross-Reactive Allergen Molecules.

Ragweed (Ambrosia artemisiifolia) pollen is a major endemic allergen source responsible for severe allergic manifestations in IgE-sensitized allergic patients. It contains the major allergen Amb a 1 and cross-reactive allergen molecules, such as the cytoskeletal protein profilin, Amb a 8 and calcium-binding allergens Amb a 9 and Amb a 10. To assess the importance of Amb a 1, profilin and calcium-binding allergen, the IgE reactivity profiles of clinically well-characterized 150 ragweed pollen-allergic patients were analysed regarding specific IgE levels for Amb a 1 and cross-reactive allergen molecules by quantitative ImmunoCAP measurements, IgE ELISA and by basophil activation experiments. By quantifying allergen-specific IgE levels we found that Amb a 1-specific IgE levels accounted for more than 50% of ragweed pollen-specific IgE in the majority of ragweed pollen-allergic patients. However, approximately 20% of patients were sensitized to profilin and the calcium-binding allergens, Amb a 9 and Amb a 10, respectively. As shown by IgE inhibition experiments, Amb a 8 showed extensive cross-reactivity with profilins from birch (Bet v 2), timothy grass (Phl p 12) and mugwort pollen (Art v 4) and was identified as a highly allergenic molecule by basophil activation testing. Our study indicates that molecular diagnosis performed by the quantification of specific IgE to Amb a 1, Amb a 8, Amb a 9 and Amb a 10 is useful to diagnose genuine sensitization to ragweed pollen and to identify patients who are sensitized to highly cross-reactive allergen molecules present in pollen from unrelated plants, in order to enable precision medicine-based approaches for the treatment and prevention of pollen allergy in areas with complex pollen sensitization.

Carbohydrate epitopes currently recognized as targets for IgE antibodies.

Until recently, glycan epitopes have not been documented by the WHO/IUIS Allergen Nomenclature Sub-Committee. This was in part due to scarce or incomplete information on these oligosaccharides, but also due to the widely held opinion that IgE to these epitopes had little or no relevance to allergic symptoms. Most IgE-binding glycans recognized up to 2008 were considered to be "classical" cross-reactive carbohydrate determinants (CCD) that occur in insects, some helminths and throughout the plant kingdom. Since 2008, the prevailing opinion on lack of clinical relevance of IgE-binding glycans has been subject to a reevaluation. This was because IgE specific for the mammalian disaccharide galactose-alpha-1,3-galactose (alpha-gal) was identified as a cause of delayed anaphylaxis to mammalian meat in the United States, an observation that has been confirmed by allergists in many parts of the world. Several experimental studies have shown that oligosaccharides with one or more terminal alpha-gal epitopes can be attached as a hapten to many different mammalian proteins or lipids. The classical CCDs also behave like haptens since they can be expressed on proteins from multiple species. This is the explanation for extensive in vitro cross-reactivity related to CCDs. Because of these developments, the Allergen Nomenclature Sub-Committee recently decided to include glycans as potentially allergenic epitopes in an adjunct section of its website (www.allergen.org). In this article, the features of the main glycan groups known to be involved in IgE recognition are revisited, and their characteristic structural, functional, and clinical features are discussed.

Profile Shift in Latex Sensitization over the Last 20 Years.

BACKGROUND: Natural rubber latex (NRL) allergy is commonly diagnosed according to medical history, skin allergy tests, and serological analyses. However, skin tests are increasingly being abandoned because of (i) their time-consuming nature, (ii) latex preparations for skin tests being not commercially available, and (iii) the use of in-house prepared test solutions is becoming ever more difficult due to increasing regulatory hurdles. In this light, we have evaluated differences in the profiles of current and former patients with suspected latex allergy. METHODS: Sera of skin test-positive patients from a historic cohort (1995-2001, n = 149 patients) and currently (2014-2015, n = 48 patients) were simultaneously analyzed for specific IgE to latex by ImmunoCAP. If the serological screening was positive (≥0.35 kU/L), component-resolved diagnostics including profilins and cross-reactive carbohydrate determinants (CCDs) were performed. RESULTS: In contrast to 88% (131/149) of the skin test-positive patients from the 1990s, only 51.1% (24/47) of the current cohort were found positive for specific IgE to latex. While 48.3% (72/149) of the patients had a convincing positive history in the 1990s, current skin test-positive patients rarely reported a relevant medical history (8.5%, 4/47). Specific IgE levels to latex were significantly higher in former patients with suspected latex allergy (p < 0.001) than in former sensitized individuals without allergy. However, this significant difference was lost in current allergic and sensitized patients with positive skin tests. CONCLUSION: Sensitization profiles in patients with latex allergy have changed significantly over the last 2 decades. Discrimination between NRL sensitization and clinical allergy remains a diagnostic challenge. Our data highlight the need for a combination of all 3 criteria, i.e., patient history, skin test, and analysis of specific IgE, for a correct diagnosis of latex allergy.

False-Positive Results of Serological Tests for Allergy in Alcoholic Patients.

BACKGROUND AND OBJECTIVE: Alcohol consumption is associated with enhanced TH2 immune responses. Objective: To investigate the frequency of false-positive results in serological tests for allergy in alcoholic patients. METHODS: A total of 138 alcoholic patients consecutively admitted to hospital underwent a panel of allergy tests that included serum total IgE, a multiallergen IgE test (UniCAP Phadiatop), and skin prick tests to relevant aeroallergens in the area, which were considered the standard reference for atopy. In selected cases with positive specific IgE (sIgE) to cross-reactive carbohydrate determinants (CCDs) on ImmunoCAP, we determined sIgE to hymenoptera venom components (ADVIA Centaur) and a microarray of 103 allergen components (ISAC). RESULTS: Increased serum total IgE (>170 IU/mL) was observed in 59/110 (54%) of nonatopic (skin prick test-negative) patients. The result of the multiallergen IgE test was positive in 46 nonatopic patients (42%). This finding was closely associated with high serum concentrations of total IgE and sIgE to CCDs. The vast majority of patients with positive CCD-sIgE showed positivity to glycosylated plant and hymenoptera allergen components on ISAC and ADVIA Centaur. Only 1 out of 26 patients with positive sIgE to CCD and hymenoptera venom developed honeybee venom allergy after a median follow-up of 166 months. Correlations between measurements of sIgE to CCD markers on ImmunoCAP, ADVIA Centaur, and ISAC were imperfect. CONCLUSIONS: Serological tests for allergy should be interpreted with caution in alcoholic patients, who frequently have increased levels of total IgE and CCD-sIgE and subsequent positivity of sIgE to glycosylated allergen components, irrespective of the method used.

ImmunoCAP cellulose displays cross-reactive carbohydrate determinant (CCD) epitopes and can cause false-positive test results in patients with high anti-CCD IgE antibody levels.

BACKGROUND: Cross-reactive carbohydrate determinants (CCDs) in plants and insect venoms are a common cause of irrelevant positive test results during in vitro allergy diagnosis. We observed that some CCD-positive sera show nonspecific IgE binding even with CCD-free recombinant allergens when using the Phadia ImmunoCAP platform. OBJECTIVE: We investigated whether cellulose used as an allergen carrier in ImmunoCAP harbors residual N-glycans, causing nonspecific background binding in CCD-positive sera. METHODS: IgE binding to 6 samples of blank ImmunoCAPs coupled to either streptavidin (SA-CAP-1 or 2) or nonallergenic maltose-binding protein (MBP; MBP-CAP-1 to 4) and binding to a panel of 4 recombinant allergens were compared in CCD-positive sera before and after inhibition with a CCD inhibitor (MUXF3-human serum albumin). RESULTS: Of 52 CCD-positive sera (bromelain, 1.01-59.6 kilounits of antigen per liter [kUA/L]) tested on SA-CAP-1, 35 (67%) showed IgE binding of greater than 0.35 kUA/L (0.41-4.22 kUA/L). Among those with anti-CCD IgE levels of greater than 7.0 kUA/L, 90% (26/29) were positive. IgE binding to SA-CAP-1 correlated with IgE binding to bromelain (r = 0.68) and was completely abolished by serum preincubation with the CCD inhibitor (n = 15). Binding scores with SA-CAP-2 and MBP-CAP-1 to MBP-CAP-4 were generally lower but strongly correlated with those of SA-CAP-1 and bromelain. IgE reactivity of 10 CCD-positive sera (14.0-52.5 kUA/L) with the recombinant allergens rPhl p 12, rFel d 1, rAra h 2, and rPru p 3 was positive to at least 1 allergen in 8 of 10 (0.36-1.63 kUA/L) and borderline in 2 of 10 (0.21-0.25 kUA/L). Binding correlated with antibody binding to bromelain (r = 0.61) and to all blank ImmunoCAPs (r > 0.90) and could be completely blocked by the CCD inhibitor. Overall, mean background binding to cellulose CCDs corresponded to 2% to 3% of the reactivity seen with bromelain. CONCLUSIONS: Cellulose used as a solid-phase allergen carrier can contain varying amounts of CCDs sufficient to cause false-positive test results up to 2 kUA/L with nonglycosylated recombinant allergens in patients with high levels of anti-CCD IgE antibodies.

Inhibition of Cross-Reactive Carbohydrate Determinants in Allergy Diagnostics.

Despite being clinically largely irrelevant, antibodies against cross-reactive carbohydrate determinants (CCD) are an important issue in the in vitro diagnostics, as they may produce false positive or falsely elevated results of the immunoglobulin E class (asIgE) in relation to the actually present level of asIgE. The present chapter demonstrates an effective resolution of this diagnostic issue by the use of a CCD inhibitor in in vitro tests. A synthetic CCD inhibitor, Polycheck® CCD inhibitor, was used in the laboratory diagnostics of 24 children diagnosed with allergic diseases. The anti-CCD antibody content was measured in the serum using a Polycheck® Atopic 30-I panel (Biocheck GmbH; Münster, Germany), a screening assay for the quantitative determination of multiple allergen-specific IgE. We found that the baseline anti-CCD antibody content, without the CCD inhibitor, ranged from 0.7 to 3.5 kU/L in the sera of the majority of 16 out of 24 children. When the CCD inhibitor was applied, the anti-CCD antibody content decreased in 16, remained unchanged in 3, and increased in 5 samples. In samples positive for plant allergens, the asIgE content dropped by an average of 72% when the CCD inhibitor was used in the assay, except the antibodies to tree and grass pollen allergens, for which the asIgE content remained above 100 kU/L. We conclude that the use of a CCD inhibitor in in vitro assays is a viable option to mitigate the influence of anti-CCD antibodies on the measured level of asIgE immunoglobulin, which increase the reliability of testing particularly in cases displaying multiple allergies.

Glycans and glycan-specific IgE in clinical and molecular allergology: Sensitization, diagnostics, and clinical symptoms.

Glycan-specific IgE antibodies cross-react with highly similar or even identical carbohydrate structures on a variety of different natural allergens, the so-called cross-reactive carbohydrate determinants (CCDs). In clinical practice CCDs often interfere with the specificity of in vitro allergy diagnostics, thus impairing allergy therapy decisions for individual patients. Strikingly, these IgE antibodies directed against CCDs often do not cause clinically relevant allergy symptoms. On the other hand, the IgE-binding glycan allergen galactose-α-(1,3)-galactose (α-Gal) is associated with IgE-mediated delayed anaphylaxis in meat allergy. The reason for this discrepancy is not known. The discovery of α-Gal stimulated new discussions and investigations regarding the relevance of anti-glycan IgE for allergic diseases. In this review the effect of glycans and glycan-specific IgE on sensitization to allergens and allergy diagnosis is described. Because parasite infections elicit a similar immunologic environment as allergic diseases, the association of glycan-specific antibodies against parasite glycoproteins with glycan structures on allergens is discussed.

Antigenic cross-reactivity between Schistosoma mansoni and peanut: a role for cross-reactive carbohydrate determinants (CCDs) and implications for the hygiene hypothesis.

The antigenic reactivity of constituents of Schistosoma mansoni and peanut (Arachis hypogaea) was investigated to determine whether identical antigenic epitopes possessed by both organisms provided a possible explanation for the negative correlation between chronic schistosome infection and atopy to allergens. Aqueous extracts of peanuts were probed in Western immunoblots with rabbit IgG antibodies raised against the egg, cercarial and adult worm stages of S. mansoni. Several molecules in the peanut extract were antigenically reactive with antibodies from the various rabbit anti-schistosome sera. A pair of cross-reactive peanut molecules at ~30 000-33 000 molecular weight was purified and both proteins were identified by mass spectrometric analysis as the peanut allergen Ara h 1. Anti-S. mansoni soluble egg antigen antibodies that were eluted off the peanut molecules reacted with two S. mansoni egg antigens identified by mass spectrometry as IPSE/α-1 and κ-5. Alignments of the amino acid sequences of Ara h 1 and either IPSE/α-1 or κ-5 revealed a low level of peptide sequence identity. Incubation of nitrocellulose paper carrying electrophoresed peanut molecules, six constituents of other allergic plants and S. mansoni egg antigens in a mild solution of sodium metaperiodate before probing with antibodies, inhibited most of the cross-reactivities. The results are consistent with the antigenic cross-reactive epitopes of S. mansoni egg antigens, peanut and other allergic plants being cross-reactive carbohydrate determinants (CCDs). These findings are novel and an explanation based on 'blocking antibodies' could provide an insight for the inverse relationship observed between schistosome infection and allergies.

Peanut-specific IgE antibodies in asymptomatic Ghanaian children possibly caused by carbohydrate determinant cross-reactivity.

BACKGROUND: The prevalence of peanut allergy has increased in developed countries, but little is known about developing countries with high peanut consumption and widespread parasitic infections. OBJECTIVE: We sought to investigate peanut allergy in Ghana. METHODS: In a cross-sectional survey among Ghanaian schoolchildren (n = 1604), data were collected on reported adverse reactions to peanut, peanut sensitization (serum specific IgE and skin reactivity), consumption patterns, and parasitic infections. In a subset (n = 43) IgE against Ara h 1, 2, 3, and 9 as well as cross-reactive carbohydrate determinants (CCDs) was measured by using ImmunoCAP. Cross-reactivity and biological activity were investigated by means of ImmunoCAP inhibition and basophil histamine release, respectively. RESULTS: Adverse reactions to peanut were reported in 1.5%, skin prick test reactivity in 2.0%, and IgE sensitization (≥0.35 kU/L) in 17.5% of participants. Moreover, 92.4% of those IgE sensitized to peanut (≥0.35 kU/L) had negative peanut skin prick test responses. Schistosoma haematobium infection was positively associated with IgE sensitization (adjusted odds ratio, 2.29; 95% CI, 1.37-3.86). In the subset IgE titers to Ara h 1, 2, 3, and 9 were low (<1.3 kU/L), except for 6 moderately strong reactions to Ara h 9. IgE against peanut was strongly correlated with IgE against CCDs (r = 0.89, P < .0001) and could be almost completely inhibited by CCDs, as well as S haematobium soluble egg antigen. Moreover, IgE to peanut showed poor biological activity. CONCLUSIONS: Parasite-induced IgE against CCDs might account largely for high IgE levels to peanut in our study population of Ghanaian schoolchildren. No evidence of IgE-mediated peanut allergy was found.

Diagnosis of Hymenoptera Venom Allergy: State of the Art, Challenges, and Perspectives.

Hymenoptera venom allergy is the most common cause of anaphylaxis in adults and the second-most frequent in children. The proper diagnosis of this life-threatening allergy remains a challenge. This review focuses on the current knowledge regarding diagnostics of Hymenoptera venom allergy. The paper includes a brief description of the representatives of Hymenoptera order and the composition of their venoms. Then, diagnostic tests for allergy to Hymenoptera venom are described. Common diagnostic problems, especially double positivity in tests for IgE antibodies specific to honeybee and wasp venom, are also discussed. Special attention is paid to the search for new diagnostic capabilities using modern methodologies. Multidimensional molecular analysis offers an opportunity to characterize changes in body fluids associated with Hymenoptera venom allergy and yields a unique insight into the cell status. Despite recent developments in the diagnostics of Hymenoptera venom allergy, new testing methodologies are still needed to answer questions and doubts we have.

Comparative mass spectrometry analysis of N-glycans from the glycoproteins of eight allergy-inducing plants.

Extensive cross-allergic reactivity exists among food-borne plants. As most allergens are glycoproteins, protein sensitization has been extensively studied. However, little attention has been given to the glycan component of glycoproteins. Here, we qualitatively and quantitatively compared the N-glycans of eight cross-reactive plant glycoproteins derived from peach pollen, soy, pine nut, cashew nut, pistachio, walnut, almond, and hazelnut. Cross-reactive carbohydrate determinants (CCDs) were widely present in the allergic glycoproteins according to the following order: pollen > soybean > pistachios > pine nuts > walnuts > cashews > hazelnuts > almonds. The N-glycan structure presented clear differences between the germplasm and vegetative tissue. Importantly, fucosylation and xylosylation levels correlated positively with extensive cross-reactivity between plants, which suggests that CCDs may be one of the causes of cross-allergy. This result provides the foundation for mechanistic studies on plant-derived CCDs as a source of food cross-allergies.

Major Grass Pollen Allergen Components and Cross-Reactive Carbohydrate Determinants in Mugwort-Sensitized Child Patients With Allergic Respiratory Disease in Western China.

Mugwort is a common pollen allergen in western China, and this study aimed to investigate the patterns of molecular sensitization to major grass pollen allergens (mugwort, ragweed, bermuda grass, and timothy grass) and cross-reactive carbohydrate determinants (CCD) in children who were sensitized to mugwort in western China. Serum-specific IgE (sIgE) of major allergen components and CCD were detected among 121 mugwort SPT-positive children via the EUROBlotMaster system if the mugwort-sIgE was positive (MSP). A CCD inhibition test was further performed on the serum of patients with positive CCD-sIgE. Latent class analysis was used to identify the patterns of potential sensitization to major grass pollen allergens. Of a total of 100 patients with mugwort-sIgE positive (MSP), 52.0, 41.0, and 31.0% of them were positive to Art v 1, Art v 3, and Art v 4, respectively. An optimal model with three latent classes was determined using grass pollen allergens, components, and CCD. The sensitization patterns can be summarized as (1) MSP and cosensitized to ragweed, bermuda grass, and timothy grass (23.74%); (2) MSP and cosensitized to Art v 1 (54.08%); (3) MSP and cosensitized to Art v 4, Cyn d 12, Phl p 12 (22.18%). Additionally, CCD sIgE levels had a significant positive correlation with ragweed, bermuda grass, and timothy grass (P < 0.05), and CCD-Inhibitor can highly inhibit the above allergens sIgE. Our findings suggest that Art v 4 was the typical cross-reaction component of mugwort, which is cosensitized to Phl p 12 and Cyn d 12. A wide cross-reaction among ragweed, bermuda grass, and timothy grass caused by CCD was observed.

Complex IgE sensitization patterns in ragweed allergic patients: Implications for diagnosis and specific immunotherapy.

Background: Ragweed (Ambrosia artemisiifolia) is one of the most important allergen sources, worldwide, causing severe respiratory allergic reactions in late summer and fall, in sensitized patients. Amb a 1 has been considered as the most important allergen in ragweed but 12 ragweed pollen allergens are known. The aim of our study was to investigate IgE reactivity profiles of ragweed allergic patients and to associate them with clinical symptoms. Methods: IgE sensitization profiles from clinically well-characterized ragweed allergic patients (n = 150) were analyzed using immunoblotted ragweed pollen extract. Immunoblot inhibition experiments were performed with two Amb a 1 isoforms and CCD markers and basophil activation experiments were performed with IgE serum before and after depletion of Amb a 1-specific IgE. Results: By IgE-immunoblotting 19 different IgE reactivity patterns with and without Amb a 1-sensitization were found. The majority of patients (>95%) suffered from rhino-conjunctivitis, around 60% reported asthma-like symptoms and about 25% had skin reactions. Patients with complex IgE sensitization profiles tended to have more clinical symptoms. Serum with and without Amb a 1-specific IgE induced basophil activation. Conclusions: Ragweed pollen allergic patients exhibit complex IgE reactivity profiles to ragweed allergens including Amb a 1 isoforms and cross-reactive carbohydrates indicating the importance of Amb a 1 isoforms and additional allergens for diagnosis and allergen-specific immunotherapy of ragweed allergy.

CCD Inhibition Test Can Improve the Accuracy of the Detection of Pollen and Seed Food Allergen-Specific IgE in Southern China.

OBJECTIVE: The presence of cross-reactive carbohydrate determinants (CCDs) may cause false-positive results in vitro allergen sIgE tests. In this paper, we focused on pollen sensitisation and its relationship with CCD in patients with respiratory allergic diseases in South China. A CCD inhibition test was conducted to assess whether patients were truly allergic to pollen or whether their sIgE was caused by a CCD cross-reaction, thus providing an important basis for clinical diagnosis and treatment. METHODS: Patients with known serologic pollen sensitization were selected, and sIgE of mugwort, tree mix 20 (willow/poplar/elm tree), common ragweed, Humulus scandens, peanut, soybean and CCD was detected via the EUROBlotMaster system. Thirteen CCD-sIgE negative patients and 33 CCD-positive patients were selected, and their serum samples were subjected to the CCD inhibition test. RESULTS: We found that 66.0% to 95.9% of patients sensitised to pollen and seed food allergens were co-sensitized to CCD. Additionally, 73.0% to 100% of the sIgE tests for pollen and seed food allergens turned negative after inhibition, mostly for allergens from Humulus scandens (100%, 15/15), followed by mugwort and peanut (85.2%, 23/27), ragweed (81.5%, 22/27), soybean (80.0%, 20/25), and tree pollen (73.0%, 19/26). CONCLUSION: CCD causes false positives in the in vitro allergen sIgE tests of patients with respiratory allergic diseases in South China. Attention should be paid to the use of CCD inhibitors in diagnosing in vitro allergies because of their importance in diagnosing and treating local allergic diseases.

Component-resolved diagnosis in adult patients with food-dependent anaphylaxis.

Food anaphylaxis is a severe, potentially life-threatening, systemic hypersensitivity reaction. Within a retrospective study we applied ImmunoCAP-ISAC in a heterogenous cohort of 54 food anaphylactic patients and compared its performance to conventional in vitro (ELISA, ImmunoCAP) and in vivo (skin prick test, oral food challenge) diagnosis. Comparing clinical diagnosis with results obtained by ImmunoCAP-ISAC we obtained moderate agreement (kappa 0.524, p < 0.05). The comparison between SPT and ImmunoCAP vs ImmunoCAP-ISAC indicates a good sensitivity of microarray testing. Among the 54 tested sera, 36 and 41 were in substantial agreement with results obtained by SPT (69%, kappa 0.667, p < 0.05) and ImmunoCAP-ISAC (76%, kappa 0.759, p < 0.05), respectively. Within this adult anaphylaxis cohort, plant food allergens were identified as the predominant IgE-binding proteins, with PR10 proteins, ω-5-gliadin and nsLTPs as the most frequent ones. In summary, microarray based IgE testing may help to unravel the elicitating food in anaphylaxis in particular when the elicitor is so far unknown.

Major Pollen Allergen Components and CCD Detection in Bermuda Grass Sensitized Patients in Guangzhou, China.

OBJECTIVE: Bermuda grass pollen is a common inhaled allergen. The aim of this study was to investigate the molecular sensitization patterns to major pollen allergens (Bermuda grass, Mugwort and Timothy grass) and cross-reactive carbohydrate determinants (CCD) in Bermuda grass sensitized patients in southern China. METHODS: Serum specific IgE (sIgE) levels of Bermuda grass allergen components (Cyn d 1 and Cyn d 12), Timothy grass allergen components (Phl p 1, Phl p 4, Phl p 5, Phl p 7 and Phl p 12), Mugwort allergen components (Art v 1, Art v 3 and Art v 4) and CCD were detected in 78 patients sensitized to Bermuda grass via EUROBlotMaster system. RESULTS: Compared with CCD-positive patients, those with negative CCD results had significant higher positive rates of Cyn d 1 (47.8% vs 14.5%), Phl p 1 (26.1% vs 7.3%), Phl p 12 (21.7% vs 3.6%) and Art v 4 (26.1% vs 3.6%) (all p < 0.05). Patients <18 years old had the highest positive rate of Cyn d 1 (40.7%). Additionally, rhinitis patients had the highest positive rate of Cyn d 1 (60.0%), and all patients with Cyn d 12 sensitization (17.2%) were asthmatic patients. Optimal scale analysis showed that Phl p 1 and Cyn d 1 were closely related (Cronbach's alpha = 85.1%). CONCLUSION: The highest positive rate of pollen allergen components was Cyn d 1 in Bermuda grass sensitized patients in southern China. Most patients were sensitized to CCD alone, and CCD may have less interference in the detection of Cyn d 1, Art v 4, Phl p 1 and Phl p 12. The sensitization patterns of pollen allergen components varied in different ages and diseases, and the diagnostic strategy of pollen allergen needs to be considered in the future.

Linking cross-reactivity clusters of food and respiratory allergens in PAMD@ to asthma and duration of allergy.

BACKGROUND: Component resolved diagnosis, recently redefined as precision allergy medicine diagnosis - PAMD@, may help understanding allergic cross-reactivity patterns among polysensitized patients and their clinical implication. OBJECTIVE: We aimed to investigate similarities among allergens by empirically determining the occurrence of co-sensitization patterns and to relate them to clinical features, in particular to asthma. METHODS: A retrospective cohort study in 1057 participants suspected to have allergic sensitization was performed in Vienna. To define cross-reactivity patterns, cluster analysis for 671 patients who showed reaction to at least one of the allergens in ISAC112 was performed and followed by multivariate logistic regression analysis to relate clusters and clinical symptoms, in particular current asthma. RESULTS: We determined 18 cross-reactivity clusters, comprising of 6 food, 10 respiratory, and 2 other clusters of allergens. Overall, 14% of the cohort patients were positive for 1 cross-reactivity cluster and 23% to 2 or more clusters. Multisensitized patients who were sensitized to PR-10 allergen proteins in addition to Bermuda timothy grass pollen clusters showed the highest association with asthma (odds ratio, 4.22 and 95% CI: 2.32-7.68) and an increase of 10 years of the duration of allergy increased the odds for a combined sensitization to PR-10 cluster and Bermuda-timothy cluster by 1.27 (95% CI: 1.06-1.53). CONCLUSION: Similarities among IgE positivity patterns determined by ISAC112 revealed 18 cross-reactivity clusters. This PAMD@ approach allowed prediction of clinical features and revealed that certain cross-reactivity patterns are related to duration of allergic symptoms.

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.