Specific IgE Responses Research Articles

Gut microbiome impact on childhood allergic rhinitis and house dust mite IgE responses.

The correlation between the gut microbiota and airway inflammation in childhood allergic rhinitis (AR), particularly concerning allergen exposure, remains insufficiently explored. This study aimed to link gut microbiota changes with house dust mite (HDM)-specific IgE responses in pediatric AR. Using metagenomic shotgun sequencing, we compared the fecal microbiota of 60 children with HDM-AR to 48 healthy controls (HC), analyzing the link to IgE reactions. We examined the effects of oral Escherichia (E.) fergusonii treatment in mice sensitized with ovalbumin and HDM on allergic symptoms, mucosal cell infiltration, Th1/Th2/Tregs balance in the spleen, serum cytokine levels, and E. fergusonii presence in feces. Children with HDM-AR have a less diverse gut microbiome and lower levels of E. fergusonii compared to controls, with a negative correlation between E. fergusonii abundance and HDM-specific IgE levels. In mice sensitized with OVA and HDM, oral administration of E. fergusonii improved allergic symptoms, reduced nasal eosinophils/mast cells infiltration and adjusted Th cell populations towards a non-allergic profile in splenic lymphocytes with exception of IFN-γ change in serum. These findings underline the potential of targeting gut microbiota, particularly E. fergusonii, in managing childhood HDM-AR, suggesting a promising approach for future interventions. The composition and distribution of gut microbiota in children with HDM-AR are significant changed. The abundance of Escherichia genus is decreased in HDM-AR children. HDM-specific IgE levels are strongly negatively associated with E. fergusonii abundance. Oral administration of E. fergusonii effectively suppresses allergic responses in murine model. These findings offer novel insights into the diagnosis and treatment of HDM-AR, which suggested that E. fergusonii holds promise as a potential therapeutic avenue for managing HDM-AR.

Glutenin from the Ancient Wheat Progenitor Is Intrinsically Allergenic as It Can Clinically Sensitize Mice for Systemic Anaphylaxis by Activating Th2 Immune Pathway.

Wheat allergy is a major type of food allergy with the potential for life-threatening anaphylactic reactions. Common wheat, Triticum aestivum (hexaploid, AABBDD genome), was developed using tetraploid wheat (AABB genome) and the ancient diploid wheat progenitor (DD genome)-Aegilops tauschii. The potential allergenicity of gluten from ancient diploid wheat is unknown. In this study, using a novel adjuvant-free gluten allergy mouse model, we tested the hypothesis that the glutenin extract from this ancient wheat progenitor will be intrinsically allergenic in this model. The ancient wheat was grown, and wheat berries were used to extract the glutenin for testing. A plant protein-free colony of Balb/c mice was established and used in this study. The intrinsic allergic sensitization potential of the glutenin was determined by measuring IgE response upon transdermal exposure without the use of an adjuvant. Clinical sensitization for eliciting systemic anaphylaxis (SA) was determined by quantifying the hypothermic shock response (HSR) and the mucosal mast cell response (MMCR) upon intraperitoneal injection. Glutenin extract elicited a robust and specific IgE response. Life-threatening SA associated and a significant MMCR were induced by the glutenin challenge. Furthermore, proteomic analysis of the spleen tissue revealed evidence of in vivo Th2 pathway activation. In addition, using a recently published fold-change analysis method, several immune markers positively and negatively associated with SA were identified. These results demonstrate for the first time that the glutenin from the ancient wheat progenitor is intrinsically allergenic, as it has the capacity to elicit clinical sensitization for anaphylaxis via activation of the Th2 pathway in vivo in mice.

Aeroallergen sensitization patterns in children with allergic rhinitis from Guangzhou and Liuzhou in southern China

<sec><title>Background</title><p>The sensitization patterns of allergic rhinitis (AR) to allergens exhibit global variations, influenced by diverse geographical, climatic, cultural, and genetic determinants. We aimed to contrast the allergen profiles among children belonging to distinct ethnic groups residing in two disparate provinces of China, with the objective of elucidating the impact of environmental and genetic factors on the types of allergens.</p></sec><sec><title>Methods</title><p>A comparative analysis was conducted on allergen sensitizations among children with allergic rhinitis (AR) in Guangzhou and Liuzhou from 2019 to 2023. The specific IgE response to a range of inhalant allergens was evaluated utilizing the ImmunoCAP 100 system. Statistical analysis was conducted using the SPSS 20 software package. For comparisons, the Chi-square test or Fisher's exact test was employed, depending on the nature of the data and the assumptions of each test.</p></sec><sec><title>Results</title><p>A total of 9684 AR children from Guangzhou and 1679 from Liuzhou were enrolled in the study. Notably, the sensitization rates toward D. <italic>farinae</italic>, <italic>D. pteronyssinus</italic>, cat dander, dog dander, common ragweed, and mugwort were significantly elevated in Guangzhou compared to Liuzhou. However, the sensitization rates to cockroaches exhibited no notable disparities between the two cities.</p></sec><sec><title>Conclusions</title><p>The allergen composition in AR children is similar between Guangzhou and Liuzhou, with <italic>D. farina</italic> and <italic>D. pteronyssinus</italic> as the main allergens. However, the sensitization rates of all allergens except for cockroaches in Guangzhou are higher than those in Liuzhou. Our results suggest that the causes of allergen sensitization are complex, and genetic and environmental factors cannot be ignored.</p></sec>

Advocacy of Precision Allergy Molecular Diagnosis in Decision Making for the Eligibility of Customized Allergen Immunotherapy.

Allergen immunotherapy (AIT) with aeroallergens is the only disease-modifying treatment for patients with different allergic conditions. Despite the effectiveness of AIT having been proven in both randomized controlled trials and real-world studies, it remains underused in less than 10% of subjects with allergic rhinitis (AR) and/or asthma (A). We aimed to determine the current eligibility for house dust mite (HDM) AIT by means of a precision allergy molecular diagnosis (PAMD@) model in a selected cohort of youngsters with different allergic phenotypes according to the available evidence. A complex response to both HDM and storage mite allergens was depicted regardless of the subjects' basal atopic condition. No solely specific IgE-binding responses to Der p 1, Der p 2, and/or Der p 23 were found in the studied cohort. Despite the patients with A and atopic dermatitis showing significantly higher serum titers to six mite allergens than subjects with AR, no specific molecular profile was regarded as disease specific. Given the increasing complexity of specific IgE responses to the local prevailing aeroallergens, the identification and presence of such molecules are needed in commercially available AIT in the era of precision medicine.

Early inhalant allergen sensitization at component level: an analysis in atopic Dutch children.

Allergic rhinitis is a common respiratory disease in children and sensitization to inhalant allergens plays a significant role in its development. However, limited knowledge exists regarding sensitization profiles of inhalant allergen components in atopic children, particularly in the very young individuals. Understanding these profiles could provide insights into the early development of allergic rhinitis. The objective of this cross-sectional retrospective study was to evaluate the IgE-sensitization profiles to multiple inhalant allergen components and their clinical relevance in Dutch atopic children, with specific focus on children under the age of 4 years. A total of 243 atopic children were included in the study and sensitization profiles were analyzed using multiplex microarray analysis (ISAC). Clinical information was obtained from records of a pediatric allergy outpatient clinic between 2011 and 2020. Specific IgE responses to inhalation allergen components from five allergen sources (grass pollen, tree pollen, house dust mite, cat and dog), were examined. The study encompassed children of different age groups and compared those with and without symptoms. The results demonstrated that sensitization to inhalant allergen components was present in 92% of the cohort. Sensitization was already evident at a young age (87%), including infancy, with a rapid increase in prevalence after 1 year of age. House dust mite emerged as the most predominant sensitizing allergen in early childhood, followed by tree pollen in later years. Sensitization patterns were similar between symptomatic and asymptomatic children, although symptomatic children exhibited higher frequencies and values. The sensitization profiles in very young children were comparable to those of children across all age groups. These findings highlight the presence of sensitization to inhalant allergen components and the early onset of allergic rhinitis before the age of 4, including infancy, in Dutch atopic children. Notable allergen molecules in Dutch atopic children under the age of 4 years include Bet v 1, Fel d 1, Der f 1, Der p 1, Der p 10 and Phl p 4, with house dust mite sensitization being the most common among Dutch infants. Moreover, the prevalence of sensitization to inhalant allergens in this Dutch cohort surpassed that of general European populations, emphasizing the importance of early assessment and management of allergic rhinitis in young atopic children.

Evaluation of salt-soluble protein extract from an ancient wheat progenitor (Aegilops tauschii) for intrinsic allergenicity in an adjuvant-free mouse model of wheat allergy

Abstract Wheat allergies are a growing significant health concern around the globe. The ancient diploid wheat progenitor, Aegilops tauschii (genome DD), contributed to the genetic diversity of the common soft white wheat (Triticum aestivum, genomes AABBDD). The allergenic potential of Ae. tauschii is largely unknown. Here we tested the hypothesis that the the salt-soluble protein extract (SSPE) from Ae. tauschii will be intrinsically allergenic in an adjuvant-free mouse model of wheat allergy. The ancient wheat progenitor was grown at the Michigan State University greenhouse using the seeds stored at our wheat breeding program. The SSPE was prepared, characterized for quality, and then tested in the mouse model that uses skin sensitization followed by oral allergen challenge. Balb/c mice were produced and maintained on a plant protein-free diet. Groups of adult mice (n=10/group) were repeatedly exposed to SSPE or vehicle via the skin. Allergic sensitization was assessed by specific IgE (sIgE) response. Oral anaphylaxis was quantified by hypothermic shock response (HSR). The mucosal mast cell response (MMCR) was quantified by measuring MMCP-1 in the blood. Repeated skin exposure to SSPE but not the vehicle elicited robust sIgE response. Oral SSPE challenge but not vehicle challenge elicited significant, but a modest HSR as well as MMCR. In summary, we report the characterization of intrinsic allergenicity potential of the SSPE obtained from the Ae. tauschii wheat progenitor for the first time. Funding: USDA/NIFA. The United States Department of Agriculture (USDA)/National Institute of Food and Agriculture (NIFA); Hatch project MICL02486 (Accession Number: 1012322); Hatch project MICL01699; Agricultural and Food Research Initiative Competitive Program, grant number: 2018-67017-27876

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.

Specific IgE Response and Omalizumab Responsiveness in Severe Allergic Asthma.

Omalizumab has demonstrated clinical efficacy in patients with severe allergic asthma sensitized to perennial allergens and/or severe pollinosis through inhibition of IgE-dependent allergic response. When considering the "one airway, one disease" concept, sensitization to pollen could predict responsiveness to omalizumab. This study aimed to assess whether the pretreatment specific IgE response could be a predictor of responsiveness to omalizumab in severe allergic asthma sensitized to perennial allergens. In this retrospective study, 41 adult patients with severe allergic asthma sensitized to perennial allergens (27 females; mean age 59 years) who had completed 52-week omalizumab treatment were enrolled. The Global Evaluation of Treatment Effectiveness was performed, and demographic characteristics and the positive ratios of specific IgE responses classified into five subgroups (pollen, dust mite, house dust, mold, and animal dander) were compared between responders and non-responders. Multivariate logistic regression analyses were performed to identify predictors of responsiveness to omalizumab. Thirty-one patients (76%) were identified as responders. The number of sensitized aeroallergen subgroups and sensitization to pollens were significantly higher in responders than in non-responders (both p<0.05). Multivariate logistic regression analysis showed that sensitization to pollen (OR = 8.41, p = 0.02) was independently associated with the effectiveness of omalizumab. Pretreatment serum pollen-specific IgE could be a predictor of responsiveness to omalizumab.

IL-13 determines specific IgE responses and SARS-CoV-2 immunity after mild COVID-19 and novel mRNA vaccination.

After recovery, mild and severe COVID-19 diseases are associated with long-term effects on the host immune system, such as prolonged T-cell activation or accumulation of autoantibodies. In this study, we show that mild SARS-CoV-2 infections, but not SARS-CoV-2 spike mRNA vaccinations, cause durable atopic risk factors such as a systemic Th2- and Th17-type environment as well as activation of B cells responsive of IgE against aeroallergens from house dust mite and mold. At an average of 100 days post mild SARS-CoV-2 infections, anti-mold responses were associated with low IL-13 levels and increased pro-inflammatory IL-6 titers. Acutely severely ill COVID-19 patients instead showed no evidence of atopic reactions. Considering convalescents of mild COVID-19 courses and mRNA-vaccinated individuals together, IL-13 was the predominant significantly upregulated factor, likely shaping SARS-CoV-2 immunity. Application of multiple regression analysis revealed that the IL-13 levels of both groups were determined by the Th17-type cytokines IL-17A and IL-22. Taken together, these results implicate a critical role for IL-13 in the aftermath of SARS-CoV-2 mild infections and mRNA vaccinations, conferring protection against airway directed, atopic side reactions that occur in mildly experienced COVID-19.

Allergic rhinitis in Chinese young adults from the Singapore/Malaysia cross-sectional genetics epidemiology study (SMCGES) cohort: Prevalence, patterns, and epidemiology of allergic rhinitis

BackgroundAllergic rhinitis (AR) is characterized by the occurrence of at least 2 symptoms of nasal itching, nasal blockage, rhinorrhea, and sneezing, when not afflicted with a cold or flu, with defined atopic sensitization demonstrated by skin prick test or specific IgE responses. Besides the detriment to standard of living and economic burden of AR, both multicentre and single-cohort studies have observed an increase in AR prevalence in Asia over time. MethodsIn total, 12 872 individuals, with mean age 22.1 years (SD = 4.8), were recruited from universities in Singapore and Malaysia. Each participant provided epidemiological data based on an investigator-administered questionnaire adapted from the validated International Study of Allergies and Asthma in Childhood (ISAAC) protocol, and atopy status was determined using a skin prick test (SPT) performed by qualified staff. AR was diagnosed according to Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines and a positive SPT result. ResultsSensitization (determined by SPT) to either Blomia tropicalis or Dermatophagoides pteronyssinus was prevalent in 66.5% of the cohort. Current rhinitis (manifesting ≥2 rhinitis symptoms, within the past 12 months) was observed in 48.9% of our population, while AR, which included atopy status, was estimated at 39.4%. Sneezing and rhinorrhea were the most common symptoms among AR cases. AR prevalence decreased with increasing age (OR: 0.979; 95% CI: 0.969–0.989), while male gender (OR: 2.053; 95% CI: 1.839–2.294), and a parental history of allergic diseases (OR: 2.750; 95% CI: 2.284–3.316) were significant risk factors for AR. Upon adjustment for age, gender, and parental history, housing type (OR: 0.632; 95% CI: 0.543–0.736) and income level (>$6000 vs <$2000; OR: 2.461; 95% CI: 2.058–2.947) remained as significant risk factors for AR, while ever having kept a pet (OR: 1.167; 95% CI: 1.025–1.328) emerged as a risk factor. Conflicting results were obtained for indicators of sedentary lifestyle: frequent physical activity (OR: 1.394; 95% CI: 1.150–1.694) and increased duration spent using the TV/computer (OR: 1.224; 95% CI: 1.006–1.489) both increased the risk of AR. Lastly, we used the Quality of Diet based on Glycaemic Index Score (QDGIS) to assess the Glycaemic Index (GI) level of overall diet. We identified lower GI level of overall diet as a protective factor against AR manifestation (OR: 0.682; 95% CI: 0.577–0.807). ConclusionWhile the previously established non-modifiable risk factors for AR were present in our study population, the identification of modifiable risk factors, such as TV/computer usage, and dietary habits, opens a new area for research, both in the areas of gene-environment interaction, and management of AR.

Clinical and Immunologic Changes due to Subcutaneous Immunotherapy With Cat and Dog Extracts Using an Ultrarush Up-Dosing Phase: AReal-Life Study.

We aimed to evaluate the efficacy of and immunologic changes caused by subcutaneous immunotherapy (SCIT) in patients with allergy to cat and dog. The study population comprised patients with rhinitis and/or asthma and allergy to cat or dog from a previous safety study. All patients had specific IgE to cat and/or dog. The SCIT maintenance dose was administered using an infusion pump over a single 4-hour session, followed by monthly administration over 6 months. Data were gathered on clinical outcomes, pulmonary function, FeNO, rhinitis and asthma symptoms, quality of life (QOL), and scores for the Asthma Control Test and symptom visual analog scale were recorded at baseline and then at 1, 3, and 6 months. Specific IgE and IgG antibody responses to cat and dog allergens were determined. The study population comprised 61 patients with a mean age of 35.6 (9.7) years, of whom 40 underwent SCIT for at allergy. A significant improvement was observed in rhinitis and asthma symptoms and in QOL, use of medication, visual analog scale score, and Asthma Control Test score at 1 month; these improvements persisted at month 6. The clinical improvement with cat extract was significantly more marked than with dog extract. Nearly half of the patients (49.09%) had an increase of >0.9 in the ESPRINT-15 QOL in allergic rhinitis questionnaire, and 58.18% had an increase of >0.5 in the Asthma Quality of Life Questionnaire score at month 6. Both differences represent the minimal clinical important difference. A significant increase was observed in specific IgG and IgE to different allergens at 3 and/or 6 months. Ultrarush SCIT with cat and dog extracts has substantial clinical value for many patients.

CD4+ and CD8+CD60+ T cells in PBMC of IgE+ allergic adults express IL-4 or IFN alpha but not IFN gamma, and some express receptors for complement split products (CSP) C3a and C5a

We previously reported that two distinct T cell subsets (CD4+ and CD8+CD60+) and IL-4, IFN alpha, and IFN gamma, but not IL-13, were required for human ragweed specific memory IgE responses. Nevertheless, the exact subsets producing these cytokines and their numbers are unknown, as are the numbers of C3a+ or C5a+ receptor T cells expressing IL-4.

Distributions of T cell subsets expressing receptors for complement split products (CSP) C3a or C5a in blood of serum IgE+ aeroallergen allergic adults

Previous studies demonstrated that CD4+ T cells and IL-4 are required for human and rodent IgE responses. We demonstrated that two distinct T cell subsets (CD4+, CD8+CD60+) and 6 cytokines (including IL-4, IFN alpha, IFN gamma, but not IL-13) are required for human ragweed specific memory IgE responses. However, little is known about events upstream of T cell participation leading to IgE production. Antigen/allergen cleaves complement, but it is unknown if/which T cells express receptors for CSP.

Hypersensitivity in the lungs is responsible for acute respiratory failure in COVID-19 patients: Case series of patients who received high-dose/short-term methylprednisolone.

BackgroundCOVID‐19 is a highly contagious respiratory disease caused by the SARS‐CoV‐2 virus. Patients with severe disease have a high fatality rate and face a huge medical burden due to the need for invasive mechanical ventilation. Hypoxic respiratory failure is the major cause of death in these patients. There are currently no specific anti‐SARS‐CoV‐2 drugs, and the effect of corticosteroids is still controversial.MethodsThe clinical data of 102 COVID‐19 patients, including 27 patients with severe disease, were analyzed. The serum levels of total IgE and anti‐SARS‐CoV‐2 specific IgE were compared in healthy controls and COVID‐19 patients, changes in the level of anti‐SARS‐CoV‐2 specific IgE and clinical response to methylprednisolone (MP) treatment were analyzed, and the effect of high‐dose/short‐term MP therapy for patients with critical illness and respiratory failure was determined.ResultsCOVID‐19 patients had elevated serum levels of anti‐SARS‐CoV‐2 specific IgE, and patients with severe disease, especially critical illness, had even higher levels. Application of short‐term/high‐dose MP significantly reduced the level of these IgE antibodies and also blocked the progression of hypoxic respiratory failure. Hypoxic respiratory failure in patients with COVID‐19 is related to pulmonary hypersensitivity.ConclusionsHypersensitivity in the lungs is responsible for acute respiratory failure in COVID‐19 patients. Application of high‐dose/short‐term MP appears to be an effective life‐saving method for COVID‐19 patients who have hypoxic respiratory failure.

Sensitization Potency of Sunflower Seed Protein in a Mouse Model: Identification of 2S-Albumins More Allergenic Than SFA-8.

ScopeFood allergy to sunflower seed (SFS) protein is not frequent and only non‐specific lipid transfert protein (nsLTP) Hel a 3 is officially recognized as a food allergen. Out of the eleven seed storage 2S‐albumins (SESA) detected in SFS, only SFA‐8 allergenicity has been investigated so far. The study aimed then to evaluate SFS protein allergenicity and particularly, to compare the sensitization potency of SESA in a mouse model.Methods and ResultsThe most abundant SESA and nsLTP were isolated from SFS through a combination of chromatographic methods. Purified proteins were then used to measure specific IgG1 and IgE responses in BALB/c mice orally sensitized to different SFS protein isolates. The study, thus, confirmed the allergenicity of SFA‐8 and Hel a 3 but mice were also highly sensitized to other SESA such as SESA2‐1 or SESA20‐2. Furthermore, competitive inhibition of IgE‐binding revealed that SFA‐8 IgE‐reactivity was due to cross‐reactivity with other SESA. 11S‐globulins were weakly immunogenic and were rapidly degraded in an in vitro model of gastroduodenal digestion. In contrast, Hel a 3, SESA2‐1 and SFA‐8 were more resistant to proteolysis and gastroduodenal digestion did not affect their IgE‐reactivity.ConclusionsSESA2‐1 or SESA20‐2 were more potent allergens than SFA‐8 in this mouse model. Allergenicity of SESA must be now confirmed in SFS‐allergic patients.

Dectin-1 Controls TSLP-Induced Th2 Response by Regulating STAT3, STAT6, and p50-RelB Activities in Dendritic Cells.

The epithelium-associated cytokine thymic stromal lymphopoietin (TSLP) can induce OX40L and CCL17 expression by myeloid dendritic cells (mDCs), which contributes to aberrant Th2-type immune responses. Herein, we report that such TSLP-induced Th2-type immune response can be effectively controlled by Dectin-1, a C-type lectin receptor expressed by mDCs. Dectin-1 stimulation induced STAT3 activation and decreased the transcriptional activity of p50-RelB, both of which resulted in reduced OX40L expression on TSLP-activated mDCs. Dectin-1 stimulation also suppressed TSLP-induced STAT6 activation, resulting in decreased expression of the Th2 chemoattractant CCL17. We further demonstrated that Dectin-1 activation was capable of suppressing ragweed allergen (Amb a 1)-specific Th2-type T cell response in allergy patients ex vivo and house dust mite allergen (Der p 1)-specific IgE response in non-human primates in vivo. Collectively, this study provides a molecular explanation of Dectin-1-mediated suppression of Th2-type inflammatory responses and suggests Dectin-1 as a target for controlling Th2-type inflammation.

Modulation of Allergic Sensitization and Allergic Inflammation by Staphylococcus aureus Enterotoxin B in an Ovalbumin Mouse Model.

The superantigen Staphylococcus aureus (S. aureus) enterotoxin B (SEB) has been proposed a central player in the associations between S. aureus nasal colonization and the development of allergic asthma. Previously, SEB has been shown to aggravate allergic sensitization and allergic airway inflammation (AAI) in experimental mouse models. Aiming at understanding the underlying immunological mechanisms, we tested the hypothesis that intranasal (i.n.) SEB-treatment divergently modulates AAI depending on the timing and intensity of the SEB-encounter. In an ovalbumin-mediated mouse model of AAI, we treated mice i.n. with 50 ng or 500 ng SEB either together with the allergic challenge or prior to the peripheral sensitization. We observed SEB to affect different hallmark parameters of AAI depending on the timing and the dose of treatment. SEB administered i.n. together with the allergic challenge significantly modulated respiratory leukocyte accumulation, intensified lymphocyte activation and, at the higher dose, induced a strong type-1 and pro-inflammatory cytokine response and alleviated airway hyperreactivity in AAI. SEB administered i.n. prior to the allergic sensitization at the lower dose significantly boosted the specific IgE response while administration of the higher dose led to a significantly reduced recruitment of immune cells, including eosinophils, to the respiratory tract and to a significantly dampened Th-2 cytokine response without inducing a Th-1 or pro-inflammatory response. We show a remarkably versatile potential for SEB to either aggravate or alleviate different parameters of allergic sensitization and AAI. Our study thereby not only highlights the complexity of the associations between S. aureus and allergic asthma but possibly even points at prophylactic and therapeutic pathways.

Cul o 2 specific IgG3/5 antibodies predicted Culicoides hypersensitivity in a group imported Icelandic horses

BackgroundCulicoides hypersensitivity (CH) is induced in horses by salivary allergens of Culicoides midges. In Iceland, the causal Culicoides species for CH are not present. Previous epidemiological data indicated that Icelandic horses are more susceptible to CH when they are exported from Iceland and first exposed to Culicoides at adult age. Horses born in countries where Culicoides is endemic, develop the disease less frequently. Here, we established a longitudinal allergy model to identify predictive and diagnostic serological biomarkers of CH.ResultsSixteen adult Icelandic horses from Iceland were imported to the Northeastern United States (US) during the winter and were kept in the same environment with natural Culicoides exposure for the next two years. None of the horses showed clinical allergy during the first summer of Culicoides exposure. In the second summer, 9/16 horses (56%) developed CH. Allergen specific IgE and IgG isotype responses in serum samples were analysed using nine potential Culicoides allergens in a fluorescent bead-based multiplex assay. During the first summer of Culicoides exposure, while all horses were still clinically healthy, Cul o 2 specific IgG3/5 antibodies were higher in horses that developed the allergic disease in the second summer compared to those that did not become allergic (p = 0.043). The difference in Cul o 2 specific IgG3/5 antibodies between the two groups continued to be detectable through fall (p = 0.035) and winter of the first year. During the second summer, clinical signs first appeared and Cul o 3 specific IgG3/5 isotypes were elevated in allergic horses (p = 0.041). Cul o 2 specific IgG5 (p = 0.035), and Cul o 3 specific IgG3/5 (p = 0.043) were increased in late fall of year two when clinical signs started to improve again.ConclusionsOur results identified IgG5 and IgG3/5 antibodies against Cul o 2 and Cul o 3, respectively, as markers for CH during and shortly after the allergy season in the Northeastern US. In addition, Cul o 2 specific IgG3/5 antibodies may be valuable as a predictive biomarker of CH in horses that have been exposed to Culicoides but did not yet develop clinical signs.

Allergen-like Molecules from Parasites.

Parasite infections modulate immunologic responses, and the loss of parasite infections in the last two to three decades might explain the increased prevalence of allergic diseases in developed countries. However, parasites can enhance allergic responses. Parasites contain or release allergen-like molecules that induce the specific immunoglobulin, IgE, and trigger type-2 immune responses. Some parasites and their proteins, such as Anisakis and Echinococcus granulosus allergens, act as typical allergens. A number of IgE-binding proteins of various helminthic parasites are cross-reactive to other environmental allergens, which cause allergic symptoms or hamper accurate diagnosis of allergic diseases. The cross-reactivity is based on the fact that parasite proteins are structurally homologous to common environmental allergens. In addition, IgE-binding proteins of parasites might be useful for developing vaccines to prevent host re-infection. This review discusses the functions of the IgE-biding proteins of parasites.

Cellular and Humoral Responses to Cte f 2, a Cat Flea Allergen, in Children with Papular Urticaria

Background: Papular urticaria (PU) is a common insect bite skin hypersensitivity in tropical countries. In order to gain insight into its causal allergens, we aimed to evaluate cellular and humoral immune responses to the recombinant salivary antigen Cte f 2 from the cat flea Ctenocephalides felis. Method: Sixty patients with PU and 27 healthy controls were included in this study. Specific IgE, IgG, IgG1, and IgG4 against Cte f 2 and C. felis extract were determined by ELISA. The T-cell response was analyzed using a carboxyfluorescein succinimidyl ester (CFSE)-based dilution assay and Th1/Th2/Th17 cytokine measurements. In addition, a proteomic analysis of IgG and IgE reactive spots of C. felis extract was performed. Results: The frequency of IgE sensitization to Cte f 2 was similar between patients (36.7%) and controls (40.7%). The specific IgE, IgG1, and IgG4 responses to Cte f 2 and C. felis extract were not significantly different between patients and controls. Among the 3 conditions (i.e., Cte f 2, C. felis extract, and only medium) Cte f 2 was the strongest inducer of CD3+CD4+ proliferation in the patients; however, the mean response was not significantly different from those in controls (Cte f 2: 4.5 vs. 2.5%; p = 0.46). No salivary proteins were identified in C. felis, and most of the spots were identified as muscle-skeletal components (tropomyosin, actin, myosin, and ankirin). Conclusions: Cte f 2 induces IgE and IgG production as well as T-cell proliferation in children living in a geographical area where PU induced by a flea bite is common. The use of C. felis extract is not recommended for the study of bite-induced hypersensitivity disease since salivary antigens are not well represented.