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Background: The domestic mite Blomia tropicalis is a major source of allergens in tropical and subtropical regions. Despite its great medical importance, the allergome of this mite has not been sufficiently studied. Only 14 allergen groups have been identified in B. tropicalis thus far, even though early radioimmunoelectrophoresis techniques (27 uncharacterized allergen complexes) and comparative data based on 40 allergen groups officially recognized by the World Health Organization (WHO)/IUIS in domestic astigmatid mites suggest the presence of a large set of additional allergens. Methods: Here, we employ a multiomics approach to assess the allergome of B. tropicalis using genomic and transcriptomic sequence data and perform highly sensitive protein abundance quantification. Findings: Among the 14 known allergen groups, we confirmed 13 (one WHO/IUIS allergen, Blo t 19, was not found) and identified 16 potentially novel allergens based on sequence similarity. These data indicate that B. tropicalis shares 27 known/deduced allergen groups with pyroglyphid house dust mites (genus Dermatophagoides). Among these groups, five allergen‐encoding genes are highly expressed at the transcript level: Blo t 1, Blo t 5, Blo t 21 (known), Blo t 15, and Blo t 18 (predicted). However, at the protein level, a different set of most abundant allergens was found: Blo t 2, 10, 11, 20 and 21 (mite bodies) or Blo t 3, 4, 6 and predicted Blo t 13, 14 and 36 (mite feces). Interpretation: We report the use of an integrated omics method to identify and predict an array of mite allergens and advanced, label‐free proteomics to determine allergen protein abundance. Our research identifies a large set of novel putative allergens and shows that the expression levels of allergen‐encoding genes may not be strictly correlated with the actual allergenic protein abundance in mite bodies. [ABSTRACT FROM AUTHOR]

Background: Understanding differences in sensitization profiles at the molecular allergen level is important for diagnosis, personalized treatment and prevention strategies in allergy. Methods: Immunoglobulin E (IgE) sensitization profiles were determined in more than 2800 sera from children in nine population‐based cohorts in different geographical regions of Europe; north [BAMSE (Sweden), ECA (Norway)], west/central [PIAMA (the Netherlands), BiB (the United Kingdom), GINIplus (Germany)], and south [INMA Sabadell and Gipuzkoa (Spain) and ROBBIC Rome and Bologna (Italy)] using the MeDALL‐allergen chip. Results: Sensitization to grass pollen allergen, Phl p 1, and to major cat allergen, Fel d 1, dominated in most European regions whereas sensitization to house dust mite allergens Der p 1, 2 and 23 varied considerably between regions and were lowest in the north. Less than half of children from Sabadell which has a hot and dry climate were sensitized to respiratory allergens, in particular house dust mite allergens as compared to Gipuzkoa nearby with a more humid climate. Peanut allergen Ara h 1 was the most frequently recognized class 1 food allergen in Northern/Western Europe, while the fruit allergens Pru p 3, Act d 1 and 2 were prominent in Southern and Western/Central Europe. Ves v 5‐sensitization dominated in North and West/Central Europe. Conclusion: We show regional, exposome‐ and climate‐dependent differences in molecular IgE‐reactivity profiles in Northern, Western/Central and Southern Europe which may form a molecular basis for precision medicine‐based approaches for treatment and prevention of allergy. [ABSTRACT FROM AUTHOR]

Of the 73 patients, 53 (72.6%) were positive for at least one of the four allergen components; only 30 (41.1%) were positive for mango extract in ImmunoCAP, suggesting low or lacking presence of relevant allergens in the mango extract. Mango allergy is frequently associated with pollinosis by I Artemisia i and I Betula i pollens.[[1]] Immunoglobulin E (IgE)-mediated mango allergy is the leading cause of fruit allergies in China.[3] Although several mango allergens have been identified with IgE-binding bands around 14, 17, 30, 40, 50, 60, and 67 kDa,[[2], [4], [6]] their molecular characterization is absent from the International Union of Immunological Societies (IUIS) allergen database. Specific IgE positivity against mango extract and allergen components was higher in children and teenagers than in adults (Figure 1G), indicating the increasing trend of mango allergy in younger people. [Extracted from the article]

Background: Molecular antibody reactivity profiles have not yet been studied in depth in patients treated by sublingual house dust mite (HDM) tablet immunotherapy. Humoral immune responses to a large panel of HDM mite allergens were studied using allergen microarray technology in a subset of clinically defined high and low responder patients from a double‐blind placebo‐controlled allergen‐specific immunotherapy (AIT) trial using sublingual 300 IR HDM tablets. Methods: Serum levels of IgE, IgG and IgG4 to 13 Dermatophagoides pteronyssinus molecules were measured at baseline and after 1‐year AIT, using allergen microarrays in 100 subjects exhibiting high or low clinical benefit. Results: Der p 1, Der p 2 and Der p 23 were the most frequently recognized allergens in the study population. Patients with HDM‐related asthma had significantly higher allergen‐specific IgE levels to Der p 1 and Der p 23. No significant difference in the distribution of allergen sensitization pattern was observed between high and low responders. An increase in serum allergen‐specific IgG and IgG4 occurred upon AIT, in particular to allergens Der p 1, Der p 2 and Der p 23 (p < 0.0001). Conclusions: We confirm for our study population that Der p 1‐ and Der p 23‐specific IgE levels are associated with asthma. IgE reactivity profiles were not predicitive of sublingual AIT outcomes, with 300 IR tablets as efficacious in pauci‐ and multi‐sensitized subjects. Our study is the first to demonstrate the induction of IgG and IgG4 specific for the HDM allergens Der p 1, Der p 2 and Der p 23 by sublingual AIT. [ABSTRACT FROM AUTHOR]

Background: The Dermatophagoides pteronyssinus molecule Der p 23 is a major allergen whose clinical relevance has been shown in cross‐sectional studies. We longitudinally analysed the trajectory of Der p 23‐specific IgE antibody (sIgE) levels throughout childhood and youth, their early‐life determinants and their clinical relevance for allergic rhinitis and asthma. Methods: We obtained sera and clinical data of 191 participants of the German Multicentre Allergy Study, a prospective birth cohort. Serum samples from birth to 20 years of age with sIgE reactivity to Der p 23 in a customised semiquantitative microarray were newly analysed with a singleplex quantitative assay. Early mite exposure was assessed by measuring the average content of Der p 1 in house dust at 6 and 18 months. Results: Der p 23‐sIgE levels were detected at least once in 97/191 participants (51%). Prevalence of Der p 23 sensitisation and mean sIgE levels increased until age 10 years, plateaued until age 13 years and were lowest at age 20 years. Asthma, allergic rhinitis (AR) and atopic dermatitis (AD) were more prevalent in Der p 23‐sensitised children, including those with monomolecular but persistent sensitisation (11/97, 11%). A higher exposure to mites in infancy and occurrence of AD before 5 years of age preceded the onset of Der p 23 sensitisation, which in turn preceded a higher incidence of asthma. Conclusions: Der p 23 sensitisation peaks in late childhood and then decreases. It is preceded by early mite exposure and AD. Asthma and AR can occur in patients persistently sensitised to Der p 23 as the only mite allergen, suggesting the inclusion of molecular testing of Der p 23‐sIgE for subjects with clinical suspicion of HDM allergy but without sIgE to other major D.pt. allergens. [ABSTRACT FROM AUTHOR]

Background: Sensitization to house dust mite (HDM) is a leading cause of allergic rhinitis and asthma. Despite more than 30 HDM‐derived allergens having been identified to date, specific therapeutic approaches do not yet take into account the local sensitization profiles of patients. This study aimed to identify patterns of HDM sensitization in HDM‐allergic adults living in distinct geographic areas, to inform the development of targeted diagnostic and therapeutic tools. Methods: Serum samples from 685 HDM‐allergic subjects from Canada, Europe, South Africa, and the USA were tested for levels of IgE specific for 17 micro‐arrayed HDM allergens by ImmunoCAP Immuno Solid‐phase Allergen Chip (ISAC) technology. Results: The results confirmed significant geographical variability in sensitization patterns and levels of IgE. In all areas, the major sensitizers were the group 1 and group 2 allergens and Der p 23. Der p 23 was a frequent sensitizer: 64% of the subjects had IgE specific for Der p 23, and 2.3% were monosensitized to it. In South Africa, Der p 23 was the dominant HDM allergen (86% prevalence) and Der p 7 achieved major allergen status (56%). IgE sensitization to HDM was influenced by asthmatic status, levels of allergen exposure, age, race‐ethnicity and smoking status, but not by BMI. Conclusion: Sensitization profiles to HDM allergens differ considerably among distinct geographic areas, with Der p 7 and Der p 23 being major sensitizers in South Africa. Such heterogeneity should be taken into account in the diagnosis and treatment of HDM‐allergic patients. [ABSTRACT FROM AUTHOR]

Background: In the house dust mite (HDM) Dermatophagoides pteronyssinus, Der p 1, 2, 5, 7, 21, and 23 have been identified as the most important allergens. The aim of this study was to define hypoallergenic peptides derived from the sequences of the six allergens and to use the peptides and the complete allergens to study antibody, T cell, and cytokine responses in sensitized and nonsensitized subjects. Methods: IgE reactivity of HDM‐allergic and non‐HDM‐sensitized individuals to 15 HDM allergens was established using ImmunoCAP ISAC technology. Thirty‐three peptides covering the sequences of the six HDM allergens were synthesized. Allergens and peptides were tested for IgE and IgG reactivity by ELISA and ImmunoCAP, respectively. Allergenic activity was determined by basophil activation. CD4+ T cell and cytokine responses were determined in PBMC cultures by CFSE dilution and Luminex technology, respectively. Results: House dust mite allergics showed IgE reactivity only to complete allergens, whereas 31 of the 33 peptides lacked relevant IgE reactivity and allergenic activity. IgG antibodies of HDM‐allergic and nonsensitized subjects were directed against peptide epitopes and higher allergen‐specific IgG levels were found in HDM allergics. PBMC from HDM‐allergics produced higher levels of IL‐5 whereas non‐HDM‐sensitized individuals mounted higher levels of IFN‐gamma, IL‐17, pro‐inflammatory cytokines, and IL‐10. Conclusion: IgG antibodies in HDM‐allergic patients recognize peptide epitopes which are different from the epitopes recognized by IgE. This may explain why naturally occurring allergen‐specific IgG antibodies do not protect against IgE‐mediated allergic inflammation. A mix of hypoallergenic peptides containing T cell epitopes of the most important HDM allergens was identified. [ABSTRACT FROM AUTHOR]

Summary: Background: Confirmation of the clinical relevance of sensitisation is important for the diagnosis of allergic rhinitis. Objective: To investigate the usefulness of an in vitro basophil activation test and component‐resolved diagnosis in distinguishing between symptomatic allergic rhinitis patients and asymptomatic sensitization to house dust mites (HDMs). Methods: Thirty‐six subjects with a positive skin prick test (SPT) for HDM were divided into a symptomatic (n = 17) and an asymptomatic (n = 19) group on the basis of their clinical history and a nasal provocation test. A basophil CD63 response to in vitro stimulation with Dermatophagoides pteronyssinus whole allergen extract and the IgE reactivity profiles for Der p 1, 2, 4, 5, 7, 10, 11, 14, 15, 18, 21, 23 were evaluated. Serum IgE and IgG specific to D pteronyssinus whole allergen extract and total IgE were measured. Results: There were no statistically significant differences in the levels of IgE (IgE levels were higher in symptomatic patients with P = 0.055) and IgG specific to D pteronyssinus and total IgE. Symptomatic patients showed a lower threshold for in vitro basophil activation (3.33 ng/mL vs 33.3 ng/mL), a higher area under the curve (AUC) of basophil activation (171 vs 127) (P = 0.017), a higher response to positive control with anti‐FcεRI stimulation (97% vs 79%) (P < 0.001), a recognition of more HDM allergens (4 vs 2) and more frequent sensitization to rDer p 7 (P = 0.016) and rDer p 23 compared to asymptomatic subjects (P = 0.018). There was a positive correlation (r = 0.63; P < 0.001) between the number of recognized allergens and the AUC of basophil activation. Conclusion and Clinical Relevance: In the subjects studied, the differences in the basophil response to D pteronyssinus allergen extract, number of recognized HDM allergens and reactivity to rDer p 7 and rDer p 23 distinguish symptomatic from asymptomatic HDM sensitisation better than SPT or allergen extract‐specific IgE. Information regarding the clinical relevance of sensitization is important for the prescription of allergen‐specific immunotherapy. [ABSTRACT FROM AUTHOR]

Summary: Background: Aedes aegypti and Dermatophagoides pteronyssinus contain important allergens including cross‐reactive tropomyosins. However, the functional and clinical relevance of their cross‐reactivity is still debated. Objective: To analyse the humoral and cellular cross‐reactivity of recombinant Aed a 10.01, Aed a 10.02 and Der p 10. Methods: Sera from 15 Austrian house dust mite‐allergic, Der p 10‐sensitized individuals were tested for IgE reactivity to recombinant tropomyosins in ELISA, inhibition ELISA and basophil activation tests. BALB/c mice were immunized with Aed a 10.01 or Aed a 10.02, and their sera were assessed for reactivity to all tropomyosins. Splenocytes were stimulated with all tropomyosins and synthetic peptides representing the amino acid sequence of Aed a 10.01. Results: IgE antibodies of Der p 10‐sensitized patients cross‐reacted with both tropomyosins from A. aegypti. Aed a 10.01 was a more potent inhibitor of IgE binding to Der p 10 and a stronger activator of basophils sensitized with Der p 10‐specific IgE than Aed a 10.02. Murine antibodies raised against Aed a 10.01 and Aed a 10.02 cross‐reacted with Der p 10. Aed a 10.01‐specific antibody showed stronger cross‐reactivity with Der p 10 than Aed a 10.02‐specific antibody. Splenocytes from both groups of mice proliferated similarly to all tropomyosins. Five cross‐reactive T cell‐activating regions were identified. Conclusion and Clinical relevance: Tropomyosins from D. pteronyssinus and A. aegypti show humoral and cellular cross‐reactivity, involving 5 potential T cell‐activating regions. The more pronounced cross‐reactivity of Aed a 10.01 and Der p 10 matched the higher sequence similarity of both proteins. [ABSTRACT FROM AUTHOR]

Introduction Wheat sensitization is common but IgE antibodies (IgE-abs) to wheat are not predictive of clinical symptoms in children with suspected wheat allergy. Wheat allergen components other than ω-5 gliadin have not been well studied. Our aim was to characterize the clinical profile and investigate the value of adding measurements of IgE-abs to wheat components in a group of children with a doctor's diagnosed wheat allergy. Method Sixty-three children with a doctor's diagnosis of wheat allergy confirmed sensitization to wheat and, on a wheat elimination diet, went through oral wheat challenges or had a convincing recent history of wheat allergy. IgE-ab to ω-5 gliadin, low molecular weight glutenin ( LMW-glutenin), high molecular weight glutenin ( HMW-glutenin) and a native gliadin preparation containing α-, β-, γ-, and ω-gliadin (gliadin) were analyzed. Results Twenty-six children were positive in challenge, while six children were regarded as wheat allergic due to recent anaphylactic reactions. The IgE-ab levels to all four wheat components were significantly higher in the group with wheat allergy compared to the group with no wheat allergy (p < 0.0001). Also, the severity of symptoms at challenge correlated with the IgE-ab levels to all four components (p < 0.05). IgE-ab levels to ω-5 gliadin correlated best with challenge outcome, and by additional analysis of gliadin, HMW- and LMW-glutenin IgE-abs all challenge positive children could be identified. Conclusion Many children diagnosed as wheat allergic have outgrown their allergy and are unnecessarily on a wheat-free diet. The levels of IgE-ab to wheat gluten-derived components correlated well with wheat challenge outcome and severity. [ABSTRACT FROM AUTHOR]

In atopic patients, programming towards a preferential Th2 immunity leads to IgE antibody production and cellular Th2 immunity against otherwise harmless antigens. We report the development ofprophylactic and therapeutic DNA vaccines for the major birch-pollen allergen, Bet v 1. We constructed three DNA vaccines, coding for the complete cDNA, coding for two hypoallergenic fragments or coding for a hypoallergenic Bet v 1 mutant. The protective effect was studied in mice pretreated by intradermal DNA injections, then sensitized with Bet v 1 protein. Mice pretreated with any of the three Bet v 1-specific DNA vaccines were protected against allergic sensitization to Bet v 1. Protection was characterized by a lack of Bet v 1-specific IgE production, a lack of basophil activation and an enhanced IFN-γ expression. DNA vaccines with wild-type Bet v 1 induced strong Bet v 1-specific antibody responses whereas DNA vaccines with hypoallergenic Bet v 1 derivatives induced no (fragments) or only transient (mutant) Bet v 1-specific antibody responses. A therapeutic approach with the fragment-DNA vaccine reduced IgE production and stimulated a sustained Th1 cytokine milieu. Our results demonstrate that DNA vaccines with hypoallergenic forms of the allergen specifically protect against sensitization and suppress established Th2-type responses. This concept may be applied for the development of safe and specific DNA vaccines for the prophylaxis and therapy of allergic diseases. [ABSTRACT FROM AUTHOR]

The occurrence of systemic anaphylactic side-effects in the course of allergen-specific immunotherapy has been strongly reduced by the adsorption of allergens to aluminium hydroxide, the most frequently used adjuvant in humans. Using the major timothy grass pollen allergen, Phl p 5b, in its recombinant form for immunization of mice, we demonstrate that carbohydrate-based particles (CBP) exhibit several potential advantages over aluminium-hydroxide as adjuvant for immunotherapy. Similar to alum-bound rPhl p 5b, CBP-bound rPhl p 5b induced a stronger antibody and cytokine response than unbound rPhl p 5b after subcutaneous injection in mice. The antibodies induced by CBP-bound rPhl p 5b, exhibited potentially beneficial activities as they crossreacted with group 5 allergens from five other grass species and inhibited the binding of grass pollen allergic patients IgE to Phl p 5b. Alum-bound rPhl p 5b induced a preferential allergen-specific Th2response characterized by high immunoglobulin G 1 (IgG 1) antibody levels and elevated interleukin (IL)-4 and IL-5 production in cultured splenocytes. By contrast, CBP-bound rPhl p 5b, but not rPhl p 5b alone or coadministered with CBP, induced a mixed allergen-specific T helper 1 (Thl)/Th2 immune response characterized by the additional production of allergen-specific IgG2a/b antibody responses and elevated interferon-γ production. Conjugation of rPhl p 5b to CBP yielded a stable vaccine formulation with preserved immunogenic features of the allergen and, in contrast to alum, induced no granulomatous tissue reactions. Based on these results, CBP is suggested as a potentially useful adjuvant for specific immunotherapy of IgE-mediated allergies. [ABSTRACT FROM AUTHOR]

Presents a study which aims to investigate whether tryptase and proteases released from mast cells and other effector cells in the course of allergic inflammation may cleave allergens and thus regulate allergen-induced effector cell activation.