Allergen-specific IgE Research Articles

Associations between functional constipation and non-IgE-mediated food allergy in infants and children.

The non-IgE-mediated food allergy (non-IgE-FA) is less prevalent than IgE-mediated food allergy, and their relationship with functional constipation (FC) needs to be clarified. A total of 305 infants and children with constipation treated in the Department of Pediatric Gastroenterology, Children's Hospital of Nanjing Medical University, from July 2020 to December 2021 were included in this study. Four cases with organic lesions were excluded. Among 301 diagnosed with FC, according to ROME IV criteria, 81 cases with allergy-related indicators were further evaluated for food allergy by food-specific IgG antibody test, allergen- specific IgE antibody detection, skin prick test, and food avoidance and reintroduction. A total of 45 cases with FC were diagnosed with food allergy, and the incidence rate was 15%. Among the 45 patients, 35 cases (77.8%) had FC with non-IgE-FA. The main clinical symptoms or signs included anal fissure, abdominal pain, and pain during defecation. The most prevalent allergic foods were cow's milk, eggs, fish, and shrimp. Ten (22.2%) cases reported FC with mixed food allergy, including both non-IgE-mediated and IgE-mediated food allergy. This study focused on non-IgE-mediated food allergy-related FC. Our results showed that the incidence of food allergy in infants and children with FC was 15%, which was mainly mediated by non-IgE-FA. The main clinical symptoms or signs in these cases included anal fissure, abdominal pain, and pain during defecation, and the main allergens included milk, eggs, fish, and shrimp.

Histamine 3 receptor antagonism mitigates neuroinflammation and depression-like behavior in a mouse model of food allergy

Abstract Histamine (HA) is a major allergic response mediator as well as a neuromodulatory neurotransmitter and a blood-brain barrier (BBB) regulator. Consequently, dysregulation of the central histaminergic system could offset brain homeostasis and function. Indeed, mood and behavioral disorders are often comorbid with conditions that elevate systemic HA, such as mastocytosis and allergy. We have previously shown elevated levels of brain HA and its receptor subtype H3 (H3R) in a mouse model of cow’s milk allergy (CMA). Additionally, neuroinflammation and cortical demyelination were observed in association with depression-like behavior in CMA mice. However, whether the elevated HA and H3R were responsible for the development of these cellular and behavioral pathologies is unknown. We hypothesized that the elevated brain HA leads to central histaminergic dysfunction through H3R, ultimately resulting in cortical demyelination and aberrant behaviors. To investigate the role of H3R, CMA mice were treated daily with thioperamide, a selective BBB-permeable H3R antagonist, to block the action of HA through this receptor. Despite the production of allergen-specific IgE, thioperamide prevented depression-like behavior. Thioperamide also ameliorated CMA-associated cortical demyelination and axonal loss compared to saline-treated mice. Our findings strongly suggested that H3R signaling contributed to cortical demyelination and the development of depression-like behaviors in our CMA mice. Targeting HA production or signaling may provide a therapeutic strategy to reduce the risk of neurodegeneration and associated brain dysfunction in susceptible individuals. Supported by grants from NIH (1R01AI168563-01, P20GM113123-06, and P20GM103442).

Modern approaches to the diagnosis and management of children with allergy to cow’s milk proteins

Allergy to cow’s milk proteins is the most common cause of allergic reactions in young children, with a significant impact on the quality of life of children and their families. The most significant biomarker of herbivore milk allergy is allergen-specific IgE (sIgE), which can be assessed both for the whole allergen (for example, cow’s milk (CM), mare’s milk, goat’s milk, etc.) and a specific molecule, included in their composition. This article focuses on the use of sIgE in infants with suspected cow’s milk protein allergy.

Molecular Allergy Diagnostics in Children with Cow's Milk Allergy: Prediction of Oral Food Challenge Response in Clinical Practice.

Cow's milk allergy (CMA) is the most common food allergy in early childhood. Children with CMA require a precise and punctual diagnosis. Oral food challenge (OFC) is the gold-standard procedure for diagnosing allergies, but it is laborious and requires a particular setting. The aim of the study was to identify the cutoff value of serum allergen-specific IgE values able to predict a positive response to OFC. Children with suspected CMA performed OFC with cow's milk (CM) or derivatives. Total IgE and specific IgE to raw CM, α-lactalbumin, β-lactoglobulin, and casein were measured. Seventy-two children performed OFC, and 30 (41.6%) had a positive response. The significant predictive factors were sensitization to raw CM extract (p = 0.03), α-lactalbumin (p = 0.013), β-lactoglobulin (p = 0.09), and casein (p = 0.019). The cutoff was, respectively: 5.13 kUA/L for raw CM, 1.47 for α-lactalbumin, 1.35 for β-lactoglobulin, and 4.87 for casein. This study allowed us to define a set of cutoff values for CM protein-specific IgE. However, these cutoffs should be interpreted not as a diagnostic tool for CMA but only predictive of response to OFC in a specific territory. Thus, the practical message may be that a value above the cutoff allows a good approximation to identify children to be started on OFC.

Ara h 2-specific IgE epitope-like peptides inhibit the binding of IgE to Ara h 2 and suppress lgE-dependent effector cell activation.

Clinical and experimental analyses indicate a pathognomonic role for allergen IgE crosslinking through epitope-paratope interactions as a major initial step in the cascade leading to effector cell activation and clinical manifestations of lgE-mediated food allergies. We aimed to undertake the initial development and assessment of Ara h 2-specific IgE epitope-like peptides that can bind to allergen-specific IgE paratopes and suppress effector cell activation. We performed biopanning, screening, IgE binding, selection and mapping of peptides. We generated synthetic peptides for use in all functional experiments. ImmunoCAP inhibition, basophil and mast cell activation tests, with LAD2 cells, a human mast cell line were performed. Twenty-six children or young adults who had peanut allergy were studied. We identified and selected three linear peptides (DHPRFNRDNDVA, DHPRYGP and DHPRFST), and immunoblot analyses revealed binding to lgE from peanut-allergic individuals. The peptide sequences were aligned to the disordered region corresponding to the loop between helices 2 and 3 of Ara h 2, and conformational mapping showed that the peptides match the surface of Ara h 2 and h 6 but not other peanut allergens. In ImmunoCAP inhibition experiments, the peptides significantly inhibit the binding of IgE to Ara h 2 (p < .001). In basophil and mast cell activation tests, the peptides significantly suppressed Ara h 2-induced effector cell activation (p < .05) and increased the half-maximal Ara h 2 effective concentration (p < .05). Binding of the peptides to specific IgEs did not induce activation of basophils or mast cells. These studies show that the indicated peptides reduce the allergenic activity of Ara h 2 and suppress lgE-dependent basophil and mast cell activation. These observations may suggest a novel therapeutic strategy for food allergy based on epitope-paratop blocking.

Respiratory Syncytial Virus-Specific Antibodies and Atopic Diseases in Children: A 10-Year Follow-Up.

Respiratory syncytial virus (RSV) stimulates the production of specific immunoglobulin (Ig) E and IgG4 antibodies as a hallmark of the Th2 immune response. In this paper, we evaluated the occurrence of atopic diseases in 10-year-old children who were positive for RSV-specific IgG antibodies during infancy. The prospective follow-up of 72 children included a physical examination, an International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire and the determination of RSV-specific antibodies and total and allergen-specific IgE. Children with asthma had their first wheezing episode at a younger age (χ2 8.097, df = 1, p = 0.004). RSV-specific IgG4 levels at year one were positively correlated with atopic dermatitis (AD) (tau_b = 0.211, p = 0.049) and current AD (tau_b = 0.269, p = 0.012); and RSV-specific IgE levels were positively correlated with allergic rhinitis (AR) (tau_b = 0.290, p = 0.012) and current AR (tau_b = 0.260, p = 0.025). Positive RSV-specific IgE at the age of one increased the chances of asthma occurrence by 5.94 (OR = 5.94, 95% CI = 1.05-33.64; p = 0.044) and the chances of AR by more than 15 times (OR = 15.03, 95% CI = 2.08-108.72; p = 0.007). A positive family history of atopy increased the chances of asthma occurrence by 5.49 times (OR = 5.49, 95% CI = 1.01-30.07; p = 0.049), and a longer duration of exclusive breastfeeding lowered that chance (OR = 0.63, 95% CI = 0.45-0.89; p = 0.008). Prenatal smoking increased the chances of AR occurrence by 7.63 times (OR = 7.63, 95% CI = 1.59-36.53; p = 0.011). RSV-specific IgE and RSV-specific IgG4 antibodies could be risk markers for the development of atopic diseases in children.

Associations between vitamin D, immunoglobulin E concentrations, and obesity.

The prevalence of allergies and obesity has been increased in parallel. Low vitamin D [25(OH)D] levels have been linked to both higher body mass index (BMI) and allergies. Since the activation of the 25(OH)D receptor inhibits IgE production and 25(OH)D influences the IgE response specifically, we tested the hypothesis that circulating 25(OH)D concentrations are negatively related to circulating allergen-specific IgE concentrations distinctly in a large adult population-based study cohort. Moreover, we studied VDR gene expression in paired biopsies of abdominal subcutaneous (SAT) and visceral adipose tissue (VAT). We investigated whether magnetic resonance imaging-estimated visceral (VFM) and subcutaneous fat mass (SFM) are related to 25(OH)D levels. We found gender differences in circulating 25(OH)D and IgE concentrations. Participants with obesity showed lower 25(OH)D concentrations and higher IgE concentrations were detected in women only. Interestingly, participants with high levels of 25(OH)D are leaner and have improved glucose metabolism. In women, 25(OH)D correlate significant with VFM and SFM. VDR expression is significantly higher expressed in VAT and is positive associated with circulating 25(OH)D concentration. There was no association between serum IgE and 25(OH)D in the entire cohort. Based on these data, we could confirm that low levels of 25(OH)D are linked to higher BMI but could not prove our hypothesis because there is no relationship between 25(OH)D and IgE in adults. Women with higher BMI tend to have higher IgE levels what may have clinical relevance. The association between obesity and circulating 25(OH)D/IgE is not straightforward, and further knowledge is needed.

Ni-NTA resin-based multiplexed origami device for highly efficient sensing of allergen-specific IgE

Food allergy diagnosis requires a highly sensitive detection of allergen-specific immunoglobulin E (sIgE) in the serum. Enzyme-linked immunosorbent assay (ELISA) is a classical method widely used for sIgE detection but had to rely on costly and time-consuming assay procedures, skilled technicians, and bulky equipment. Here, a multiplexed origami paper analytical device (moPAD) that is hexahistidine-tagged and integrated with a nitrilotriacetic acid-functionalized surface with nickel (Ni-NTA) was developed to achieve low-cost and high-efficiency immunosensing of multiple allergen-specific IgEs in serum. The major oyster allergens, Cra a 1, Cra a 2, and Cra a 4, were used to detect sIgE in human serum. The feasibility of the moPAD-based immunosensing strategy was successfully demonstrated by desirable sensitivities for multiple targets. The detection results of moPAD for 72 serum samples were 100% consistent with clinical test results, while 69 of these results showed no significant differences from ELISA results, demonstrating the accuracy and stability of this method. A fully integrated moPAD reduces detection time and achieves highly sensitive quantification using a simple smartphone-based readout. Efficient allergen modification of paper devices has great applicability in allergen component-resolved diagnostics. The implementation of moPAD can make the process of allergy diagnosis simpler for patients, physicians, and healthcare systems alike.

Topical Administration of Gardenia jasminoides Extract Regulates Th2 Immunity in OVA-Induced Mice.

A key feature of an allergic immune response is a T helper type 2 (Th2)-mediated response with production of allergen-specific IgE antibodies. Gardenia jasminoides extract with the crocin removed (GJExCR) has been shown to inhibit IgE-mediated allergic disease. To evaluate the efficacy and mechanism-of-action of this inhibition, GJExCR was used in an ovalbumin (OVA)-induced allergy model in BALB/C mice. Sensitization of BALB/C mice with OVA and aluminum hydroxide was performed on days 1 and 14 by intraperitoneal injection, followed by OVA challenge to the dorsal skin for 2 weeks before removal. Seven days post-challenge, mice were treated with GJExCR topically every day for 11 days. Enzyme-linked immunosorbent assay, flow cytometry analysis, real-time PCR, and western blot were performed to determine IgE and Th2 cytokine levels. Following OVA challenge, Th2 cytokine expression and both total and OVA-specific serum IgE levels increased, of which OVA-specific IgE and Th2 cytokine levels decreased after GJExCR treatment. Flow cytometry analysis revealed that GJExCR treatment decreased CD4+ and CD8+ T cell populations in the spleen and lymph nodes. In addition, treatment with GJExCR downregulated signal transducer and activator of transcription 1 (STAT1) activation and Th2 cytokine levels as compared to control. GJExCR containing geniposide downregulated STAT1 activation in HaCaT cells. These findings demonstrate that GJExCR exerts its anti-allergy effect via inhibition of STAT1 activation, thus regulating the immune response via modulation of Th2 cytokine release and IgE levels. Therefore, we propose GJExCR as a potential treatment for allergic hypersensitivity reactions.

Influence of Pore Size in Protein G'-Grafted Mesoporous Silica Nanoparticles as a Serum Pretreatment System for In Vitro Allergy Diagnosis.

Particles with the capacity to bind to immunoglobulin G (IgG) can be used for the purification of IgG or to process clinical samples for diagnostic purposes. For in vitro allergy diagnosis, the high IgG levels in serum can interfere with the detection of allergen-specific IgE, the main diagnostic biomarker. Although commercially available, current materials present a low IgG capture capacity at large IgG concentrations or require complex protocols, preventing their use in the clinic. In this work, mesoporous silica nanoparticles are prepared with different pore sizes, to which IgG-binding protein G' is grafted. It is found that for one particular optimal pore size, the IgG capture capacity of the material is greatly enhanced. The capacity of this material to efficiently capture human IgG in a selective way (compared to IgE) is demonstrated in both solutions of known IgG concentrations as well as in complex samples, like serum, from healthy controls and allergic patients using a simple and fast incubation protocol. Interestingly, IgG removal using the best-performing material enhances in vitro IgE detection in sera from patients allergic to amoxicillin. These results highlight the great translation potential of this strategy to the clinic in the context of in vitro allergy diagnosis.

Clonal evolution and stereotyped sequences of human IgE lineages in aeroallergen-specific immunotherapy

Allergic disease reflects specific inflammatory processes initiated by interaction between allergen and allergen-specific IgE. Specific immunotherapy (SIT) is an effective long-term treatment option, but the mechanisms by which SIT provides desensitization are not well understood. Our aim was to characterize IgE sequences expressed by allergen-specific B cells over a 3-year longitudinal study of patients with aeroallergies who were undergoing SIT. Allergen-specific IgE-expressing clones were identified by using combinatorial single-chain variable fragment libraries and tracked in PBMCs and nasal biopsy samples over a 3-year period with antibody gene repertoire sequencing. The characteristics of private IgE-expressing clones were compared with those of stereotyped or "public" IgE responses to the grass pollen allergen Phleum pratense (Phl p) 2. Members of the same allergen-specific IgE lineages were observed in nasal biopsy samples and blood, and lineages detected at baseline persisted in blood and nasal biopsy samples after 3 years of SIT, including B cells that express IgE. Evidence of progressive class switch recombination to IgG subclasses was observed after 3 years of SIT. Acommon stereotyped Phl p 2-specific antibody heavy chain sequence was detected in multiple donors. The amino acid residues enriched in IgE-stereotyped sequences from seropositive donors were analyzed with machine learning and k-mer motif discovery. Stereotyped IgE sequences had lower overall rates of somatic hypermutation and antigen selection than did single-chain variable fragment-derived allergen-specific sequences or IgE sequences of unknown specificity. Longitudinal tracking of rare circulating and tissue-resident allergen-specific IgE+ clones demonstrates persistence of allergen-specific IgE+ clones, progressive class switch recombination to IgG subtypes, and distinct maturation of a stereotyped Phl p 2 clonotype.

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.

Evidence that High-Affinity IgE Can Develop in the Germinal Center in the Absence of an IgG1-Switched Intermediate.

High-affinity allergen-specific IgE is essential for the severe allergic anaphylaxis response. High-affinity Abs are formed by successive rounds of selection of Ag-specific B cells in the germinal center (GC); however, several studies have shown that IgE+ GC B cells are impaired in their ability to undergo selection in the GC. A pathway, known as the "indirect switching pathway" for IgE, has been described whereby Ag-specific B cells initially switch to the IgG1 isotype and undergo affinity selection in the GC, with a secondary switch to the IgE isotype after affinity selection. In previous work, using a food allergy model in mice, we investigated how high-affinity IgE develops in the GC, but we did not test the indirect switching model. In this study, we analyzed the importance of the indirect switching pathway by constructing IgG1-cre Bcl6-fl/fl mice. In these mice, once B cells switch to IgG1, they delete Bcl6 and thus cannot enter or persist in the GC. When we tested IgG1-cre Bcl6-fl/fl mice with our food allergy model, we found that, as expected, IgG1 Abs had decreased affinity, but unexpectedly, the affinity of IgE for allergen was unchanged. IgG1-cre Bcl6-fl/fl mice underwent anaphylaxis in response to allergen, consistent with the formation of high-affinity IgE. Thus, in a food allergy response, high-affinity IgE can be efficiently formed in the absence of indirect switching to IgG1, either by direct selection of IgE+ GC B cells or indirect selection of IgM+ GC B cells that later switch to IgE.

Sensitization pattern to environmental allergens in a Japanese population.

We previously described the prevalence of allergen-specific IgE in a general population of Japanese adults. We sought to elucidate allergen sensitization patterns in this population. Serum samples had been obtained from 800 blood donors aged 20 to 59 years and living in Tokyo, Japan, in 2005 and stored in the Japanese Red Cross Society. These samples were examined for IgE levels, total and specific for 23 allergens or allergen sources correlated with allergic airway diseases using the ImmunoCAP method. Exploratory and confirmatory factor analyses were performed to uncover the relationship among allergen-specific IgE based on their titers. Hierarchical cluster analysis was executed using Ward's method based on standardized factor scores identified through factor analysis. Exploratory factor analysis revealed 6 categories of allergen-specific IgE: specific to 2 types of animals (insects and Dermatophagoides pteronyssinus/animal dander), 2 types of pollens (group 1 [Japanese cedar and cypress] and group 2 [alder, grass, and weeds]), and 2 types of microorganisms (fungi and commensal microorganisms on the skin). The Japanese population was categorized into 3 clusters: (A) nonatopic type, (B) house dust mite-dominant sensitization type, and (C) panatopic type. The panatopic group could be further classified into 2 subclusters positive and negative for fungal sensitization. This study demonstrated that a Japanese population could be divided into 3 clusters according to the sensitization pattern to 6 types of allergens.

Soluble IgE-binding factors in the serum of food-allergic patients: Possible pathophysiological role of soluble FcεRI asprotective factor.

IgE-mediated food allergy is the result of an aberrant immune response involving the interaction of a food allergen with its specific IgE bound to FcɛRI, the high affinity IgE receptor, on mast cells. Allergen-specific IgE also binds to soluble binding factors, but, their expression and role in food allergy is not well characterized. Here, we assess the prevalence and relevance of soluble IgE binding factors in food allergy and tolerance. We measured serum levels of four IgE binding factors, that is, galectin-3, galectin-9, soluble FcɛRI (sFcεRI) and soluble CD23 (sCD23) in 67 adults sensitized to peanut or hazelnut and sFcɛRI in 29 children sensitized to hen's egg. Adults without food allergen sensitization (n=17) served as healthy controls. We compared serum levels of patients and controls and assessed them, in the former, for links to clinical features including allergy and tolerance. Serum levels of sFcɛRI and sCD23, but not galectin-3 and galectin-9, significantly differ in food-sensitized patients as compared to healthy controls. A subgroup (28%) of peanut and hazelnut allergic patients had elevated sFcεRI levels, that were associated with higher total and specific IgE levels. Furthermore, sFcεRI levels were significantly higher in tolerant subjects compared to allergics. Among hazelnut allergic patients, those with high sFcεRI levels tolerated the highest protein amounts in the oral food challenge. sFcɛRI but not sCD23, galectin-3 and galectin-9 might play a role in the pathophysiology of food allergy. Its functional role or use as biomarker should be assessed in further studies.

Efficacy Of Tezepelumab In Patients With Severe, Uncontrolled Asthma By Specific Perennial Allergen Immunoglobulin E Thresholds

Allergic asthma is the most common type of asthma. The presence of allergen-specific IgE is synonymous with sensitization to that allergen, and often correlates with perennial allergy. A threshold of ≥0.35 kUA/L is generally used to define a positive result, but higher concentrations may indicate a greater degree of sensitivity. Tezepelumab, a human monoclonal antibody, blocks thymic stromal lymphopoietin. This post hoc analysis evaluated the efficacy of tezepelumab, using pooled data from phase 2b PATHWAY (NCT02054130) and phase 3 NAVIGATOR (NCT03347279) studies, in patients with perennial allergy grouped by different thresholds of serum specific IgE.

Allergen sensitization and polysensitization pattern of adults and children in an urban Sub-Saharan African setting (Libreville, Gabon).

It is believed that allergic diseases are increasing in Africa. However, the health sector in Africa has yet to catch up with this paradigm shift. We looked at the number of patients referred to us for allergy testing and investigated allergen sensitization. A retrospective analysis was done on 97 serum allergen-specific IgE results collected from patients suspected of having allergies in Libreville from 2018 to 2021. Specific IgE responses to 180 allergens were investigated. The general sensitization patterns were analyzed. Also analyzed were sensitization patterns for adults and children. The difference in the IgE-binding allergen positivity rate between groups was calculated by using the chi-square (χ2) test. The allergens most commonly causing sensitization were from mites (65%), barley (48%), peach (48%), dog and/or cat dander (44%), house dust (44%), peanut (39%), tomato (39%), cockroach (37%), crab (36%), garlic and/or onion (34%), rye (34%), egg white (32%), shrimp (32%), kiwi (32%), soya bean (32%), citrus mix (29%), cheese (27%), milk (27%), walnut (27%), ox-eye daisy (24%) and orchard grass (24%). Moreover, 60% of patients (36 of 60) were polysensitized to inhalant allergens, 53% (31 of 58) were polysensitized to food allergens, and 29% (14 of 48) were polysensitized to inhalant and food allergens; 65% of patients (53 of 81) were sensitized to allergens originating from mites, fungi (including Candida albicans, Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, and Pennicillium notatum), or bacteria (staphylococcal enterotoxin B). The sensitization pattern of allergens in our setting is rich and varied, with a high prevalence of polysensitization.

Environmental influences on childhood asthma: Allergens

Allergen exposure is associated with the development of allergen-specific sensitization, but their relationship is influenced by other contemporaneous exposures (such as microbial exposure) and the genetic predisposition of the host. Clinical outcomes of the primary prevention studies that tested the effectiveness of allergen avoidance in pregnancy and early life on the subsequent development of sensitization and asthma published to date are inconsistent. Therefore, we cannot provide any evidence-based advice on the use of allergen avoidance for the primary prevention of these conditions. The evidence about the impact of allergen exposure among and among sensitized children with asthma is more consistent, and the combination of sensitization and high exposure to sensitizing allergen increases airway inflammation, triggers symptoms, adversely impacts upon disease control, and is associated with poorer lung function in preschool age. However, there are differing opinions about the role of inhalant allergen avoidance in asthma management, and recommendations differ in different guidelines. Evidence from more recent high-quality trials suggests that mite allergen-impermeable bed encasings reduce hospital attendance with asthma attacks and that multifaceted targeted environmental control improves asthma control in children. We therefore suggest a pragmatic approach to allergen avoidance in the management of childhood asthma for clinical practice, including the recommendations to: (1) tailor the intervention to the patient's sensitization and exposure status by using titer of allergen-specific IgE antibodies and/or the size of the skin test as indicators of potential response; (2) use a multifaceted allergen control regime to reduce exposure as much as possible; and (3) start intervention as early as possible upon diagnosis.

Increased Exacerbation Burden in Allergic Polysensitized Patients with Moderate to Severe Asthma

Using a machine learning algorithm, we recently reported allergic poly-sensitization (APS) clusters based on ImmunoCAP® results as a newly recognized severity marker in adult urban asthmatics. APS clusters, based on numbers of positive allergen sensitizations and allergen-specific IgE levels can predict pulmonary function decline, total IgE levels and eosinophilia. Also, we found “superclusters” (cluster groupings) that tracked patients with either predominately seasonal or perennial allergen sensitizations.

Extract-Shaped Immune Repertoires as Source for Nanobody-Based Human IgE in Grass Pollen Allergy.

The presence of allergen-specific IgE in serum is a biomarker for allergic disease. Specific IgE antibodies for research and diagnostics, however, remain scarce. In contrast to prototypic antibodies, camelid species have evolved single domains as moiety for antigen recognition. These so-called nanobodies represent a versatile platform for the development of diagnostic and therapeutic approaches. In this study, we aimed for generating nanobodies and derived IgE formats from an extract-shaped immune repertoire. Timothy grass pollen represents a complex, but well-defined mixture of individual allergens. Therefore, a repertoire library from a timothy grass pollen extract immunised llama was established. The selection by phage display yielded 3 nanobodies with immunoreactivity to the extract. IgE-like nanobody-based human IgE (nb-hIgE) antibodies were produced in mammalian cells and assessed in different immunoassays and commercial platforms. Immunoblotting and diagnostic ImmunoCap analysis of single timothy grass pollen allergens identified the major allergens Phl p 6 and Phl p 4 as targets. Assessment of immunoreactivity further documented significant molecular cross-reactivity with pollen extract of different grass species and variant presence of allergens within extracts of Pooideae grasses. In summary, our study shows that extract-based immunisation enables the generation of allergen-specific nanobodies and derived nb-hIgE formats linking nanobody technologies with allergological applications.