IgE reactivity patterns in Asian and central European cockroach-sensitized patients reveal differences in primary sensitizing allergen sources.

Background: The prevalence of cockroach (CR) sensitization and its relevance as a trigger of allergy symptoms differs greatly in different geographic areas. Objective: This study aimed to compare molecular IgE reactivity profiles in CR-sensitized patients with perennial allergy symptoms from Hong Kong (HK) and Austria and identify the main primary sensitizers. Methods: IgE sensitization was assessed by skin prick test and/or IgE reactivity with CR extract. Molecular IgE reactivity profiles were analyzed via multiplex assay for sensitization to allergens and extracts from CR, house dust mite (HDM), shellfish, and 3 additional insect species. Results: HDM was the main primary sensitizer in both cohorts. In the HK group, genuine sensitization to CR was found in 45%, but none of the patients in the Austrian cohort was truly sensitized to that allergen source. Most patients from HK were cross-sensitized to other insects and/or shellfish, presumably by broad reactivity to tropomyosin and arginine kinase. About half of Austrian subjects lacked IgE to these pan-allergens, indicating co- but not cross-sensitization to insects and/or shellfish. Regarding IgE recognition frequencies, arginine kinases (64% HK, 10% Austria) and tropomyosins (42% HK, 15% Austria) were most frequently recognized; Bla g 4 (lipocalin) was detected in HK patients only (42%). Tropomyosin (Per a 7) was significantly more frequently recognized in patients with asthma. Sera from HDM-sensitized subjects from HK showed a higher proportion of sensitization to minor mite allergens. Conclusion: Molecular profiling identified differences between CR-sensitized allergic patients from HK and Austria in terms of primary sensitizers and molecular IgE reactivity patterns. Tropomyosin from American cockroach (Per a 7) was shown to be significantly associated with asthma symptoms and might be suitable as biomarker for more severe respiratory allergy symptoms.

Molecular IgE sensitization profiles of urban and rural children in South Africa.

BACKGROUND: Allergens can act as disease-triggering factors in atopic dermatitis (AD) patients. The aim of the study was to elucidate the molecular IgE sensitization profile in children with and without AD living in urban and rural areas of South Africa. METHODS: Specific IgE reactivity was assessed in 166 Black South African children aged 9-38 months using a comprehensive panel of microarrayed allergens. According to clinical characterization children fell in four groups, urban AD cases (n = 32), urban controls (non-AD, n = 40), rural cases (n = 49) and rural controls (non-AD, n = 45). RESULTS: IgE reactivity to at least one of the allergens was detected in 94% of urban and 86% of rural AD children. House dust mite (HDM; 81% urban, 74% rural AD) and animal-derived allergens (50% urban, 31% rural AD) were the most frequently recognized respiratory allergens, whereas IgE to pollen allergens was almost absent. Urban AD children showed significantly higher frequency of IgE reactivity (50%) to mouse lipocalin, Mus m 1, than rural AD children (12%). The most frequently recognized food allergens were from egg (63% urban, 43% rural AD), peanut (31% vs 41%), and soybean (22% vs 27%), whereas milk sensitization was rare. α-gal-specific IgE almost exclusively occurred in rural children (AD: 14%, non-AD: 49%). CONCLUSION: Molecular allergy diagnosis detects frequent IgE sensitization to HDM, animal but not pollen allergens and to egg, peanut, and soy, but not milk allergens in African AD children. Urban AD children reacted more often to Mus m 1, whereas α-gal sensitization is more common in rural children likely due to parasite exposure.

Microarray-Based Detection of Allergen-Reactive IgE in Patients with Mastocytosis.

BACKGROUND: Because of a high risk to develop fatal anaphylaxis, early detection of immunoglobulin E (IgE)-dependent allergy is of particular importance in patients with mastocytosis. OBJECTIVE: We examined whether microarray-based screening for allergen-reactive IgE (allergen-chip) is a sensitive and robust approach to detect specific IgE in patients with mastocytosis. METHODS: Sera for 42 patients were analyzed, including 4 with cutaneous mastocytosis, 2 with mastocytosis in the skin, and 36 with systemic mastocytosis. In addition, sera from an age- and sex-matched control cohort (n = 42) were analyzed. RESULTS: In 15 of 42 patients with mastocytosis (35.7%), specific IgE was detected by allergen-chip profiling. Ves v 5 and Bet v 1 were the most frequently detected allergens (Ves v 5: 16.7% of patients; Bet v 1: 11.9% of patients). Allergen reactivity was confirmed by demonstrating upregulation of CD203c on blood basophils upon exposure to the respective allergen(s) in these patients. Specific IgE was identified by chip studies in 11 of 26 patients with mastocytosis with mediator-related symptoms (42.3%) and in 4 of 14 patients with mastocytosis without symptoms (28.6%). In the cohort with known allergy, 9 of 9 patients (100%) had a positive allergen-chip result. In patients with mastocytosis without a known allergy (n = 31), the chip identified 6 positive cases (19.5%). The prevalence of chip-positive patients was slightly lower in the mastocytosis group (35.7%) compared with age- and sex-matched controls (40.5%). CONCLUSIONS: Although specific IgE may not be detectable in all sensitized patients with mastocytosis, allergy chip-profiling is a reliable screening approach for the identification of patients with mastocytosis suffering from IgE-dependent allergies.

Sensitization to grass pollen allergen molecules in a birth cohort-natural Phl p 4 as an early indicator of grass pollen allergy.

BACKGROUND: Grass pollen allergy is one of the most common allergies worldwide. OBJECTIVE: The aim of this study was to evaluate the usefulness of grass pollen allergen molecules for prediction of grass pollen allergy during childhood and up to adolescence. METHOD: Questionnaire data and sera obtained from the study subjects at the ages of 4, 8, and 16 years from the population-based Barn/Children Allergy Milieu Stockholm Epidemiology birth cohort were used. Sera from 763 representative subjects with serum samples available at all 3 ages were analyzed for IgE reactivity to 8 Phleum pratense (Phl p) allergens (MeDALL [Mechanisms for the Development of Allergies] chip) and to timothy grass extract (ImmunoCAP). Allergic rhinitis to grass pollen (ARg) was defined as upper airway symptoms during grass pollen exposure. RESULTS: The prevalence of sensitization to any Phl p molecule was higher compared with that to timothy extract at all 3 ages: at the age of 4 years, 9.7% versus 6.8%; at the age of 8 years, 28.4% versus 15.3%; and at the age of 16 years, 37.1% versus 27.1%. General estimating equations analyses revealed that among children sensitized at the age of 4 years, the overall odds ratio (OR) of later ARg (up to 16 years) was increased only for IgE reactivity to Phl p 1 (OR = 4.9) and natural Phl p 4 (OR = 6.9). The likelihood of later symptoms increased with the number of allergen molecules; at the age of 4 years, 2 or more molecules predicted ARg to 78% and 3 or more molecules predicted ARg to 95%. A positive test result for timothy extract predicted ARg to 70%. CONCLUSIONS: Natural Phl p 4 is a hitherto unrecognized early indicator of grass pollen allergy, in addition to Phl p 1. To identify grass pollen sensitization and predict later ARg, allergen molecules are of added value to timothy extract alone and may help clinicians improve prediction of grass pollen allergy.

Molecular characterization of a fungal cyclophilin allergen Rhi o 2 and elucidation of antigenic determinants responsible for IgE-cross-reactivity.

Cyclophilins are structurally conserved pan-allergens showing extensive cross-reactivity. So far, no precise information on cross-reactive IgE-epitopes of cyclophilins is available. Here, an 18-kDa IgE-reactive cyclophilin (Rhi o 2) was purified from Rhizopus oryzae, an indoor mold causing allergic sensitization. Based on LC-MS/MS-derived sequences of natural Rhi o 2, the full-length cDNA was cloned, and expressed as recombinant (r) allergen. Purified rRhi o 2 displayed IgE-reactivity and basophil degranulation with sera from all cyclophilin-positive patients. The melting curve of properly folded rRhi o 2 showed partial refolding after heat denaturation. The allergen displayed monomeric functional peptidyl-prolyl cis-trans isomerase (PPIase) activity. In IgE-inhibition assays, rRhi o 2 exhibited extensive cross-reactivity with various other cyclophilins reported as allergens from diverse sources including its homologous human autoantigen. By generating a series of deletion mutants, a conserved 69-residue (Asn81-Asn149) fragment at C terminus of Rhi o 2 was identified as crucial for IgE-recognition and cross-reactivity. Grafting of the Asn81-Asn149 fragment within the primary structure of yeast cyclophilin CPR1 by replacing its homologous sequence resulted in a hybrid molecule with structural folds similar to Rhi o 2. The IgE-reactivity and allergenic activity of the hybrid cyclophilin were greater than that of CPR1. Therefore, the Asn81-Asn149 fragment can be considered as the site of IgE recognition of Rhi o 2. Hence, Rhi o 2 serves as a candidate antigen for the molecular diagnosis of mold allergy, and determination of a major cross-reactive IgE-epitope has clinical potential for the design of next-generation immunotherapeutics against cyclophilin-induced allergies.

Prevention of allergy by virus-like nanoparticles (VNP) delivering shielded versions of major allergens in a humanized murine allergy model.

BACKGROUND: In high-risk populations, allergen-specific prophylaxis could protect from sensitization and subsequent development of allergic disease. However, such treatment might itself induce sensitization and allergies, thus requiring hypoallergenic vaccine formulations. We here characterized the preventive potential of virus-like nanoparticles (VNP) expressing surface-exposed or shielded allergens. METHODS: Full-length major mugwort pollen allergen Art v 1 was selectively targeted either to the surface or to the inner side of the lipid bilayer envelope of VNP. Upon biochemical and immunological analysis, their preventive potential was determined in a humanized mouse model of mugwort pollen allergy. RESULTS: Virus-like nanoparticles expressing shielded version of Art v 1, in contrast to those expressing surface-exposed Art v 1, were hypoallergenic as they hardly induced degranulation of rat basophil leukemia cells sensitized with Art v 1-specific mouse or human IgE. Both VNP versions induced proliferation and cytokine production of allergen-specific T cells in vitro. Upon intranasal application in mice, VNP expressing surface-exposed but not shielded allergen induced allergen-specific antibodies, including IgE. Notably, preventive treatment with VNP expressing shielded allergen-protected mice from subsequent sensitization with mugwort pollen extract. Protection was associated with a Th1/Treg-dominated cytokine response, increased Foxp3+ Treg numbers in lungs, and reduced lung resistance when compared to mice treated with empty particles. CONCLUSION: Virus-like nanoparticles represent a novel and versatile platform for the in vivo delivery of allergens to selectively target T cells and prevent allergies without inducing allergic reactions or allergic sensitization.

Recombinant glycoproteins resembling carbohydrate-specific IgE epitopes from plants, venoms and mites.

BACKGROUND: N-linked glycans present in venoms, pollen and mites are recognized by IgE antibodies from >20% of allergic patients but have low or no allergenic activity. OBJECTIVES: To engineer recombinant glycoproteins resembling carbohydrate-specific IgE epitopes from venoms, pollen and mites which can discriminate carbohydrate-specific IgE from allergenic, peptide-specific IgE. METHODS: One or two N-glycosylation sites were engineered into the N-terminus of the non-allergenic protein horse heart myoglobin (HHM) using synthetic gene technology. HHM 1 and HHM 2 containing one or two N-glycosylation sites were expressed in baculovirus-infected High-Five™ insect cells and a non-glycosylated version (HHM 0) was obtained by mutating the glycosylation motif. Recombinant HHM proteins were analyzed regarding fold and aggregation by circular dichroism and gel filtration, respectively. IgE reactivity was assessed by ELISA, immunoblotting and quantitative ImmunoCAP measurements. IgE inhibition assays were performed to study cross-reactivity with venom, plant and mite-derived carbohydrate IgE epitopes. RESULTS: HHM-glycovariants were expressed and purified from insect cells as monomeric and folded proteins. The HHM-glycovariants exhibited strictly carbohydrate-specific IgE reactivity, designed to quantify carbohydrate-specific IgE and resembled IgE epitopes of pollen, venom and mite-derived carbohydrates. IgE-reactivity and inhibition experiments established a hierarchy of plant glcyoallergens (nPhl p 4 > nCyn d 1 > nPla a 2 > nJug r 2 > nCup a 1 > nCry j 1) indicating a hitherto unknown heterogeneity of carbohydrate IgE epitopes in plants which were completely represented by HHM 2. CONCLUSION: Defined recombinant HHM-glycoproteins resembling carbohydrate-specific IgE epitopes from plants, venoms and mites were engineered which made it possible to discriminate carbohydrate- from peptide-specific IgE reactivity.

The culprit insect but not severity of allergic reactions to bee and wasp venom can be determined by molecular diagnosis.

BACKGROUND: Allergy to bee and wasp venom can lead to life-threatening systemic reactions. The identification of the culprit species is important for allergen-specific immunotherapy. OBJECTIVES: To determine a panel of recombinant bee and wasp allergens which is suitable for the identification of bee or wasp as culprit allergen sources and to search for molecular surrogates of clinical severity of sting reactions. METHODS: Sera from eighty-seven patients with a detailed documentation of their severity of sting reaction (Mueller grade) and who had been subjected to titrated skin testing with bee and wasp venom were analyzed for bee and wasp-specific IgE levels by ImmunoCAPTM. IgE-reactivity testing was performed using a comprehensive panel of recombinant bee and wasp venom allergens (rApi m 1, 2, 3, 4, 5 and 10; rVes v 1 and 5) by ISAC chip technology, ImmunoCAP and ELISA. IgG4 antibodies to rApi m 1 and rVes v 5 were determined by ELISA and IgE/IgG4 ratios were calculated. Results from skin testing, IgE serology and IgE/IgG4 ratios were compared with severity of sting reactions. RESULTS: The panel of rApi m 1, rApi m 10, rVes v 1 and rVes v 5 allowed identification of the culprit venom in all but two of the 87 patients with good agreement to skin testing. Severities of sting reactions were not associated with results obtained by skin testing, venom-specific IgE levels or molecular diagnosis. Severe sting reactions were observed in patients showing < 1 ISU and < 2kUA/L of IgE to Api m 1 and/or Ves v 5. CONCLUSION: We identified a minimal panel of recombinant bee and wasp allergens for molecular diagnosis which may permit identification of bee and/or wasp as culprit insect in venom-sensitized subjects. The severity of sting reactions was not associated with parameters obtained by molecular diagnosis.

Molecular Aspects of Allergens and Allergy.

Immunoglobulin E (IgE)-associated allergy is the most common immune disorder. More than 30% of the population suffer from symptoms of allergy which are often severe, disabling, and life threatening such as asthma and anaphylaxis. Population-based birth cohort studies show that up to 60% of the world population exhibit IgE sensitization to allergens, of which most are protein antigens. Thirty years ago the first allergen-encoding cDNAs have been isolated. In the meantime, the structures of most of the allergens relevant for disease in humans have been solved. Here we provide an update regarding what has been learned through the use of defined allergen molecules (i.e., molecular allergology) and about mechanisms of allergic disease in humans. We focus on new insights gained regarding the process of sensitization to allergens, allergen-specific secondary immune responses, and mechanisms underlying allergic inflammation and discuss open questions. We then show how molecular forms of diagnosis and specific immunotherapy are currently revolutionizing diagnosis and treatment of allergic patients and how allergen-specific approaches may be used for the preventive eradication of allergy.

Molecular aspects of allergens in atopic dermatitis.

PURPOSE OF REVIEW: Molecular allergology uses pure, mainly recombinant and structurally defined allergen molecules and allergen-derived epitopes to study mechanisms of IgE-associated allergy, to diagnose, and even predict the development of allergic manifestations and to treat and prevent IgE-associated allergies. Atopic dermatitis, a chronic inflammatory skin disease is almost always associated with IgE sensitization to allergens. However, also non-IgE-mediated pathomechanisms seem to be operative in atopic dermatitis and it is often difficult to identify the disease-causing allergens. Here we review recent work showing the usefulness of molecular allergology to study mechanisms of atopic dermatitis, for diagnosis and eventually for treatment and prevention of atopic dermatitis. RECENT FINDINGS: IgE sensitization to airborne, food-derived, microbial allergens, and autoallergens has been found to be associated with atopic dermatitis. Using defined allergen molecules and non-IgE-reactive allergen derivatives, evidence could be provided for the existence of IgE- and non-IgE-mediated mechanisms of inflammation in atopic dermatitis. Furthermore, effects of epicutaneous allergen administration on systemic allergen-specific immune responses have been studied. Multi-allergen tests containing micro-arrayed allergen molecules have been shown to be useful for the identification of culprit allergens in atopic dermatitis and may improve the management of atopic dermatitis by allergen-specific immunotherapy, allergen avoidance, and IgE-targeting therapies in a personalized medicine approach. SUMMARY: Molecular allergology allows for dissection of the pathomechanisms of atopic dermatitis, provides new forms of allergy diagnosis for identification of disease-causing allergens, and opens the door to new forms of management by allergen-specific and T cells-targeting or IgE-targeting interventions in a personalized medicine approach.

Genetic Variants in CHIA and CHI3L1 Are Associated with the IgE Response to the Ascaris Resistance Marker ABA-1 and the Birch Pollen Allergen Bet v 1.

Helminth infections and allergic diseases are associated with IgE hyperresponsiveness but the genetics of this phenotype remain to be defined. Susceptibility to Ascaris lumbricoides infection and antibody levels to this helminth are associated with polymorphisms in locus 13q33-34. We aimed to explore this and other genomic regions to identify genetic variants associated with the IgE responsiveness in humans. Forty-eight subjects from Cartagena, Colombia, with extreme values of specific IgE to Ascaris and ABA-1, a resistance marker of this nematode, were selected for targeted resequencing. Burden analyses were done comparing extreme groups for IgE values. One-hundred one SNPs were genotyped in 1258 individuals of two well-characterized populations from Colombia and Sweden. Two low-frequency coding variants in the gene encoding the Acidic Mammalian Chitinase (CHIA rs79500525, rs139812869, tagged by rs10494133) were found enriched in high IgE responders to ABA-1 and confirmed by genetic association analyses. The SNP rs4950928 in the Chitinase 3 Like 1 gene (CHI3L1) was associated with high IgE to ABA-1 in Colombians and with high IgE to Bet v 1 in the Swedish population. CHIA rs10494133 and ABDH13 rs3783118 were associated with IgE responses to Ascaris. SNPs in the Tumor Necrosis Factor Superfamily Member 13b gene (TNFSF13B) encoding the cytokine B cell activating Factor were associated with high levels of total IgE in both populations. This is the first report on the association between low-frequency and common variants in the chitinases-related genes CHIA and CHI3L1 with the intensity of specific IgE to ABA-1 in a population naturally exposed to Ascaris and with Bet v 1 in a Swedish population. Our results add new information about the genetic influences of human IgE responsiveness; since the genes encode for enzymes involved in the immune response to parasitic infections, they could be helpful for understanding helminth immunity and allergic responses. We also confirmed that TNFSF13B has an important and conserved role in the regulation of total IgE levels, which supports potential evolutionary links between helminth immunity and allergic response.

Molecular, Structural and Immunological Characterization of Der p 18, a Chitinase-Like House Dust Mite Allergen.

BACKGROUND: The house dust mite (HDM) allergen Der p 18 belongs to the glycoside hydrolase family 18 chitinases. The relevance of Der p 18 for house dust mite allergic patients has only been partly investigated. OBJECTIVE: To perform a detailed characterization of Der p 18 on a molecular, structural and immunological level. METHODS: Der p 18 was expressed in E. coli, purified to homogeneity, tested for chitin-binding activity and its secondary structure was analyzed by circular dichroism. Der p 18-specific IgG antibodies were produced in rabbits to localize the allergen in mites using immunogold electron microscopy and to search for cross-reactive allergens in other allergen sources (i.e. mites, crustacea, mollusca and insects). IgE reactivity of rDer p 18 was tested with sera from clinically well characterized HDM-allergic patients (n = 98) and its allergenic activity was analyzed in basophil activation experiments. RESULTS: Recombinant Der p 18 was expressed and purified as a folded, biologically active protein. It shows weak chitin-binding activity and partial cross-reactivity with Der f 18 from D. farinae but not with proteins from the other tested allergen sources. The allergen was mainly localized in the peritrophic matrix of the HDM gut and to a lower extent in fecal pellets. Der p 18 reacted with IgE from 10% of mite allergic patients from Austria and showed allergenic activity when tested for basophil activation in Der p 18-sensitized patients. CONCLUSION: Der p 18 is a rather genus-specific minor allergen with weak chitin-binding activity but exhibits allergenic activity and therefore should be included in diagnostic test panels for HDM allergy.

IgE Sensitization Profiles Differ between Adult Patients with Severe and Moderate Atopic Dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a complex chronic inflammatory disease where allergens can act as specific triggering factors. AIM: To characterize the specificities of IgE-reactivity in patients with AD to a broad panel of exogenous allergens including microbial and human antigens. METHODOLOGY: Adult patients with AD were grouped according to the SCORAD index, into severe (n = 53) and moderate AD (n = 126). As controls 43 patients were included with seborrhoeic eczema and 97 individuals without history of allergy or skin diseases. Specific IgE reactivity was assessed in plasma using Phadiatop®, ImmunoCap™, micro-arrayed allergens, dot-blotted recombinant Malassezia sympodialis allergens, and immune-blotted microbial and human proteins. RESULTS: IgE reactivity was detected in 92% of patients with severe and 83% of patients with moderate AD. Sensitization to cat allergens occurred most frequently, followed by sensitization to birch pollen, grass pollen, and to the skin commensal yeast M. sympodialis. Patients with severe AD showed a significantly higher frequency of IgE reactivity to allergens like cat (rFel d 1) and house dust mite (rDer p 4 and 10), to Staphylococcus aureus, M. sympodialis, and to human antigens. In contrast, there were no significant differences in the frequencies of IgE reactivity to the grass pollen allergens rPhl p 1, 2, 5b, and 6 between the two AD groups. Furthermore the IgE reactivity profile of patients with severe AD was more spread towards several different allergen molecules as compared to patients with moderate AD. CONCLUSION: We have revealed a hitherto unknown difference regarding the molecular sensitization profile in patients with severe and moderate AD. Molecular profiling towards allergen components may provide a basis for future investigations aiming to explore the environmental, genetic and epigenetic factors which could be responsible for the different appearance and severity of disease phenotypes in AD.

α-NAC-Specific Autoreactive CD8+ T Cells in Atopic Dermatitis Are of an Effector Memory Type and Secrete IL-4 and IFN-γ.

Autoreactivity may play a critical role in the chronification of atopic dermatitis (AD). Several studies showed that AD patients produce IgE Abs specific for autoantigens, and we described Th as well as CD8(+) T cells specific for the autoallergen Hom s 2, the α-chain of the nascent polypeptide-associated complex (α-NAC). This study aimed to investigate the frequency and inflammatory phenotype of autoallergen-specific CD8(+) T cells. CD8(+) T cell immunodominant epitopes of α-NAC were mapped by applying prediction softwares, and binding affinity was confirmed by stabilization of empty MHC complexes. MHC class I tetramers were assembled and binding cells were analyzed directly ex vivo by flow cytometry and in terms of single-cell assessment by ChipCytometry. We report significantly elevated numbers of α-NAC-specific peripheral T cells in sensitized patients compared with nonatopic controls. These cells secrete IL-4 and IFN-γ, and surface markers revealed significantly elevated frequencies of circulating terminally differentiated α-NAC-specific CD8(+) T cells in patients with AD compared with nonatopic donors. The observed phenotype of α-NAC-specific CD8(+) T cells indicates a role in the pathogenesis of AD.

Cytokine effects induced by the human autoallergen α-NAC.

Autoallergy is a phenomenon found in a subgroup of patients with atopic dermatitis (AD). These patients exhibit serum IgE reactivity toward autoantigens like the alpha-chain of the nascent polypeptide-associated complex (α-NAC; Hom s 2). α-NAC has been shown before to induce T-cell proliferation and secretion of IFN-γ. To elucidate the immune modulating functions α-NAC may exert, we analyzed its effects on cytokine transcription and secretion in peripheral blood mononuclear cells (PBMCs), monocytes, and CD4+ T cells. Transcription and secretion of IFN-γ, IL-17, and IL-22 were increased in α-NAC-stimulated PBMCs. As IL-17 was significantly upregulated by α-NAC, we assessed signal transduction in PBMCs and found signal transducer and activator of transcription 3 phosphorylation in α-NAC-stimulated cells. Furthermore, we could show the importance of monocyte activation by α-NAC, as isolated T cells reacted only weakly toward the stimulation. Inhibition of IL-23 p19 led to lower amounts of IL-17 in the PBMC supernatants after α-NAC stimulation. α-NAC stimulation of PBMCs from non-allergic donors resulted in secretion of IL-10, which was greatly reduced in PBMCs from α-NAC-sensitized AD patients. Our findings provide insights into the mechanisms of autoallergy, investigating the interplay of immune cells, signaling events, and cytokines, which are known to be relevant in atopic skin inflammation.

Advances in allergen-microarray technology for diagnosis and monitoring of allergy: the MeDALL allergen-chip.

Allergy diagnosis based on purified allergen molecules provides detailed information regarding the individual sensitization profile of allergic patients, allows monitoring of the development of allergic disease and of the effect of therapies on the immune response to individual allergen molecules. Allergen microarrays contain a large variety of allergen molecules and thus allow the simultaneous detection of allergic patients' antibody reactivity profiles towards each of the allergen molecules with only minute amounts of serum. In this article we summarize recent progress in the field of allergen microarray technology and introduce the MeDALL allergen-chip which has been developed for the specific and sensitive monitoring of IgE and IgG reactivity profiles towards more than 170 allergen molecules in sera collected in European birth cohorts. MeDALL is a European research program in which allergen microarray technology is used for the monitoring of the development of allergic disease in childhood, to draw a geographic map of the recognition of clinically relevant allergens in different populations and to establish reactivity profiles which are associated with and predict certain disease manifestations. We describe technical advances of the MeDALL allergen-chip regarding specificity, sensitivity and its ability to deliver test results which are close to in vivo reactivity. In addition, the usefulness and numerous advantages of allergen microarrays for allergy research, refined allergy diagnosis, monitoring of disease, of the effects of therapies, for improving the prescription of specific immunotherapy and for prevention are discussed.