The risk of respiratory symptoms on allergen exposure increases with increasing specific IgE levels

[Pitfalls in the diagnosis of house dust mite allergy]

House dust mite (HDM) is the most significant indoor allergen, responsible for not only many cases of rhinoconjunctivitis but also for many cases of bronchial asthma, rendering it of considerable socioeconomic relevance. Besides symptomatic treatment and avoidance measures, allergen immunotherapy (AIT) is crucial, as the only causal, disease-modifying therapeutic approach. However, high diagnostic certainty is essential for initiating AIT. The challenge in making a correct diagnosis lies in interpreting the demonstrated HDM sensitization regarding its clinical relevance (clinically silent sensitization vs. allergy). While the risk of allergy increases with the level of IgE titers against HDM extract, Der p 1, or Der p 2, as well as with the breadth of the molecular sensitization profile against HDM components (Der p 1, Der p 2, Der p 23), no threshold can be defined for the presence of allergy, nor can sensitization to a specific component be confidently considered allergy inducing. It should be noted that at least in Southern Bavaria, the prevalence of Der p 23 sensitization is too low to be considered a major allergen, and Der p 23 is not able to molecularly differentiate all HDM sensitizations when added to the two major allergens Der p 1 and Der p 2. Evidently, HDM possesses a diverse profile of allergens, with some relevant ones possibly yet to be described. Unfortunately, patient history does not provide a sufficient assessment of the clinical relevance of a demonstrated HDM sensitization, necessitating allergen provocation testing before initiating AIT with HDM, despite the relatively large effort involved.

Revealing clinically relevant specific IgE sensitization patterns in Hymenoptera venom allergy with dimension reduction and clustering

Background

Immunoglobulin E (IgE) blood tests are used to detect sensitizations and potential allergies. Recent studies suggest that specific IgE sensitization patterns due to molecular interactions affect an individual's risk of developing allergic symptoms.

Objective

The aim of this study was to reveal specific IgE sensitization patterns and investigate their clinical implications in Hymenoptera venom allergy.

Methods

In this cross-sectional study, 257 hunters or fishers with self-filled surveys on previous Hymenoptera stings were analyzed. Blood samples were taken to determine Hymenoptera IgE sensitization levels. Using dimensionality reduction and clustering, specific IgE for 10 Hymenoptera venom allergens were evaluated for clinical relevance.

Results

Three clusters were unmasked using novel dimensionality reduction and clustering methods solely based on specific IgE levels to Hymenoptera venom allergens. These clusters show different characteristics regarding previous systemic reactions to Hymenoptera stings.

Conclusion

Our study was able to unmask non-linear sensitization patterns for specific IgE tests in Hymenoptera venom allergy. We were able to derive risk clusters for anaphylactic reactions following hymenoptera stings and pinpoint relevant allergens (rApi m 10, rVes v 1, whole bee, and wasp venom) for clustering.

Allergen Differences and Correlation Analysis in Siblings Diagnosed with Respiratory Allergic Diseases

INTRODUCTION

Many parents of children with allergies are worried whether their subsequent children will have allergic reactions to the same allergens. Much of the current research on sibling allergens has been focused on twins; however, in real life, very few children are twins. Our study provides an opportunity to initially explore the sensitivity to allergens in siblings diagnosed with respiratory allergic diseases.

METHODS

Siblings diagnosed with bronchial asthma and/or allergic rhinitis in the Outpatient Department of Allergy Department of Yantai Yuhuangding Hospital from January 2018 to December 2021 were selected. The siblings were divided into elder group and younger group. Data of gender, age, feeding history, serum total IgE (TIgE), absolute eosinophil counts, and allergen-specific IgE (sIgE) were collected and analyzed. The sIgEs of allergens were divided into six categories and analyzed.

RESULTS

A total of 98 sibling pairs of patients were included in this study. There were no differences in the positive rates of the different types of allergens, TIgE values, and the absolute eosinophil values between the elder and younger groups and between different genders. Logistic regression analysis indicated that the elder siblings allergic to dust mites, fungi, weed pollens, or food had a statistically significant increased risk of having their younger sibling sensitive to these types of allergens (all p <0.05), and the risk of allergy to dust mites, weed pollens, and tree pollens of younger group increased with age (all p <0.05). Except for the sIgE values of dust mites, the sIgE values of the other allergens were significantly correlated between the two groups (all p <0.05).

CONCLUSION

The positive rates of different allergens were similar between siblings. Elder siblings with dust mites, fungi, weed pollen, or food allergen positivity will have younger siblings sensitive to the same types of allergens.

Pollen Sensitization Can Increase the Allergic Reaction to Non-Cross-Reactive Allergens in a Soy-Allergic Patient

During and after the pollen season, an increase in food-triggered allergic symptoms has been observed in pollen-food syndrome patients, possibly due to seasonal boosting of pollen-IgE levels. It has been suggested that consumption of birch-pollen-related foods plays a role in seasonal allergenic inflammation. However, whether this increased pollen sensitization during the pollen season can also affect the allergenicity of allergens that are non-cross-reactive with birch pollen remains in question. This study presents the case of a patient with soy allergy and pollinosis, who experiences worsening of gastrointestinal (GI) symptoms during the birch pollen season even though the eliciting food factor does not cross-react with birch pollen allergens and their homologs (e.g., Bet v 1 and Gly m 4). The results showed a notable increase in sIgE for Gly m 4 (3.3 fold) and Bet v 1 (2.6 fold) during the birch pollen season compared to outside the birch pollen season, while Gly m 5 and Gly m 6 showed only a slight increase (1.5 fold). The basophil activation test (BAT) showed that in this patient Gly m 5 and Gly m 6 are clinically relevant soy allergens, which correlates with the reported clinical symptoms to processed soy. Moreover, the BAT against raw soy shows an increase in basophil activation during the birch pollen season and a negative basophil activation result outside the birch pollen season. Thus, the worsening of GI symptoms could possibly be due to an increase in IgE receptors, an over-reactive immune system, and/or significant intestinal allergic inflammation. This case highlights the importance of including allergens that do not cross-react with birch pollen and using a functional assay such as the BAT to evaluate clinical relevance when assessing birch pollen seasonal influence on soy allergenicity.

REGN1908/1909 prevented cat allergen-induced early asthmatic responses in an environmental exposure unit

BACKGROUND

The dominant allergen in cat dander, Felis domesticus allergen 1 (Fel d 1), is a persistent trigger for allergic rhinitis and asthma symptoms.

OBJECTIVE

We evaluated the efficacy of Fel d 1 monoclonal antibodies (REGN1908/1909) in preventing cat allergen-induced early asthmatic responses (EARs) in cat-allergic patients with mild asthma.

METHODS

Patients were randomized to single-dose REGN1908/1909 600 mg (n = 29) or placebo (n = 27). The FEV₁ was measured for up to 4 hours in a cat allergen environmental exposure unit up to 85 days after dosing. Assessments included between-group differences in change from baseline in FEV₁ area under the curve (AUC; 0-2 hours) and incidence of EAR (FEV₁ reduction ≥20%).

TRIAL REGISTRATION

NCT03838731.

RESULTS

Single-dose REGN1908/1909 significantly prevented reductions in FEV₁ on days 8, 29, 57, and 85. Most REGN1908/1909 patients did not have an EAR by 4 hours (the last time point tested). In contrast, placebo-treated patients experienced a ≥20% mean FEV₁ reduction on days 8, 29, 57, and 85 after dosing, with most experiencing an EAR within 1 hour. REGN1908/1909-treated patients tolerated 3-fold higher allergen quantities (P < .05 at all time points) versus placebo. REGN1908/1909 substantially reduced skin test reactivity to cat allergen versus placebo at all time points tested (nominal P < .001). REGN1908/1909 was generally well tolerated; no serious adverse events or deaths were reported.

CONCLUSION

Single-dose REGN1908/1909 significantly prevented reductions in FEV₁ in cat-allergic patients with mild asthma on cat allergen environmental exposure unit exposure at 8 days and up to 85 days after dose.

Thunderstorm asthma in seasonal allergic rhinitis: The TAISAR study

BACKGROUND

Asthma epidemics associated with thunderstorms have had catastrophic effects on individuals and emergency services. Seasonal allergic rhinitis (SAR) is present in the vast majority of people who develop thunderstorm asthma (TA), but there is little evidence regarding risk factors for TA among the SAR population.

OBJECTIVE

We sought to identify risk factors for a history of TA and hospital presentation in a cohort of individuals with SAR.

METHODS

This multicenter study recruited adults from Melbourne, Australia, with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry results, white blood cell count, ryegrass pollen-specific (RGP-sp) IgE concentration, and fractional exhaled nitric oxide were measured to identify risk factors for a history of TA in individuals with SAR.

RESULTS

From a total of 228 individuals with SAR, 35% (80 of 228) reported SAR only (the I-SAR group), 37% (84 of 228) reported TA symptoms but had not attended hospital for treatment (the O-TA group), and 28% (64 of 228) had presented to the hospital for TA (the H-TA group). All patients in the H-TA group reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower FEV1 value and an Asthma Control Questionnaire score higher than 1.5 were associated with H-TA. Higher blood RGP-sp IgE concentration, eosinophil counts, and fractional exhaled nitric oxide level were significantly associated with both O-TA and H-TA. Receiver operating curve analysis showed an RGP-sp IgE concentration higher than 10.1 kU/L and a prebronchodilator FEV1 value of 90% or lower to be biomarkers of increased H-TA risk.

CONCLUSION

Clinical tests can identify risk of a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

Cat allergen exposure in a naturalistic exposure chamber: a prospective observational study in cat-allergic subjects

Background

To determine the proportion and reproducibility of cat‐allergic mild asthmatics with early asthmatic response (EAR) during cat allergen exposure in a naturalistic exposure chamber (NEC).

Methods

This was a prospective, observational study in 30 cat‐allergic mild asthmatics who received two 180‐min cat‐allergen (Felis domesticus allergen 1 [Fel d 1]) challenges 27 days apart in an NEC.

Results

An EAR (≥20% reduction from baseline in forced expiratory volume in 1 s [FEV1]) was observed in 67% and 52% of subjects at first and second NEC exposure, respectively, with similar median time to EAR; 44% of subjects had an EAR on days 1 and 28. Late asthmatic response (≥15% reduction in FEV1 within 24 h of NEC exit) was observed in 33% of subjects following either exposure. Average FEV1 and total nasal symptom score during NEC exposure were highly correlated within subjects between NEC exposures (r = 0.91, p < 0.0001; r = 0.73, p < 0.001), but total ocular symptom score was not. Time to EAR, but not average FEV1, was significantly associated with NEC Fel d 1 concentration, which was variable. There were no serious adverse events; 12/30 subjects experienced 20 adverse events (including asthma, 10%; headache, 10%).

Conclusions

The NEC model demonstrates that average FEV1 change is highly reproducible and has a low correlation with cat allergen levels. However, time to EAR and incidence of EAR are less reproducible and are highly correlated with NEC allergen levels. Average FEV1, rather than incidence of EAR or time to EAR, could be considered as an endpoint for interventional trials testing cat‐specific anti‐allergy therapies using an NEC.

Passive Prophylactic Administration with a Single Dose of Anti-Fel d 1 Monoclonal Antibodies REGN1908-1909 in Cat Allergen-induced Allergic Rhinitis: A Randomized, Double-Blind, Placebo-controlled Clinical Trial

Rationale: Sensitization to Fel d 1 (Felis domesticus allergen 1) contributes to persistent allergic rhinitis and asthma. Existing treatment options for cat allergy, including allergen immunotherapy, are only moderately effective, and allergen immunotherapy has limited use because of safety concerns.

Objectives: To explore the relationship among the pharmacokinetic, clinical, and immunological effects of anti–Fel d 1 monoclonal antibodies (REGN1908–1909) in patients after treatment.

Methods: Patients received REGN1908–1909 (n = 36) or a placebo (n = 37) in a phase 1b study. Fel d 1–induced basophil and IgE-facilitated allergen binding responses were evaluated at baseline and Days 8, 29, and 85. Cytokine and chemokine concentrations in nasal fluids were measured, and REGN1908–1909 inhibition of allergen–IgE binding in patient serum was evaluated.

Measurements and Main Results: Peak serum drug concentrations were concordant with maximal observed clinical response. The anti–Fel d 1 IgE/cat dander IgE ratio in pretreatment serum correlated with Total Nasal Symptom Score improvement. The allergen-neutralizing capacity of REGN1908–1909 was observed in serum and nasal fluid and was detected in an inhibition assay. Type 2 cytokines (IL-4, IL-5, and IL-13) and chemokines (CCL17/TARC, CCL5/RANTES [regulated upon activation, normal T-cell expressed and secreted]) in nasal fluid were inhibited in REGN1908–1909–treated patients compared with placebo (P < 0.05 for all); IL-13 and IL-5 concentrations correlated with Total Nasal Symptom Score improvement. Ex vivo assays demonstrated that REGN1908 and REGN1909 combined were more potent than each alone for inhibiting FcεRI- and FcεRII (CD23)–mediated allergic responses and subsequent T-cell activation.

Conclusions: A single, passive-dose administration of Fel d 1–neutralizing IgG antibodies improved nasal symptoms in cat-allergic patients and was underscored by suppression of FcεRI-, FcεRII-, and T-helper cell type 2–mediated allergic responses.

Clinical trial registered with www.clinicaltrials.gov (NCT02127801)

Question 6: What is the use of allergy testing in children with asthma?

Disagreement exists between asthma guidelines on the routine use of allergy testing in the diagnostic work-up of a child with persistent asthma, although the important role of inhalant allergy in the pathophysiology of asthma and allergic rhinitis is undisputed. The usefulness of screening for inhalant allergies in asthma is connected to the efficacy of allergen reduction measures and specific immunotherapy, both of which appear to be more effective in children than in adults. Allergen-specific exposure reduction recommendations are therefore an essential part of childhood asthma management. Such recommendations should be guided by appropriate diagnosis of inhalant allergy, based on a structured allergy history and results of sensitization tests. Specific IgE testing and skin prick testing show comparable results in identifying clinically important sensitizations. Although a therapeutic medication trial can be started pragmatically in children with asthma without diagnosing their inhalant allergy, we recommend making or excluding an accurate diagnosis of inhalant allergy.

Furry pet-related wheeze and rhinitis in pre-school children across China: Associations with early life dampness and mould, furry pet keeping, outdoor temperature, PM10 and PM2.5

BACKGROUND

Few Chinese population studies exist on early life risk factors for furry pet allergy.

OBJECTIVES

We studied childhood respiratory symptoms when in contact with furry pets in relation to early life exposure. Moreover, we studied similar environmental associations for rhinitis not related to furry pets.

METHODS

Children aged 3-6 y from day care centres in seven Chinese cities participated (N = 39,782). Parents answered a questionnaire on home environment and children's health, including rhinoconjunctivitis and wheeze when in contact with furry pets, and diagnosed rhinitis. Prenatal and postnatal outdoor temperature, PM_2.5, PM₁₀, and NO₂ were calculated using data from monitoring stations. Associations were estimated by multilevel logistic regression.

RESULTS

Totally 2% had cats, 4% dogs, and 3.2% had rhinoconjunctivitis or wheeze when in contact with furry pets (FP symptoms). Moreover, 1.1% had furry pet related diagnosed rhinitis and 7.5% had diagnosed rhinitis not related to furry pets (other diagnosed rhinitis). Prenatal PM_2.5 and PM₁₀, especially in second trimester, and a colder climate were risk factors for FP symptoms. ETS, dampness and mould, condensation on windows in wintertime, and cats and dog keeping were associated with FP symptoms. Breast feeding and frequent window opening were protective. Similar indoor associations were found for furry pet related diagnosed rhinitis. ETS, dampness and mould, window condensation, urbanization and mechanical exhaust ventilation were risk factors for other diagnosed rhinitis. Cooking with an electric stove and early life exposure to animals (cats, dogs, farm environment during pregnancy) were protective for diagnosed rhinitis not related to furry pets.

CONCLUSIONS

Prenatal outdoor PM₁₀ and PM_2.5 can be risk factors for symptoms suggestive of furry pet allergy. Early life dampness and mould can be risk factors for rhinitis related and not related to furry pets. Exposure to animals (cats, dogs, farm environment) may reduce diagnosed rhinitis not related to furry pets.

Does Air Filtration Work for Cat Allergen Exposure?

PURPOSE OF REVIEW

The goal of this review is to compress all important information and results of the research in reducing cat allergen exposure using air filtration. Fel d 1 is the major allergen responsible for IgE responses in 90 to 95% of patients with cat allergy.

RECENT FINDINGS

Reduction of cat allergen in indoor air with different air filtration systems and portable devices has been demonstrated in the majority of the studies. Recently, early and late asthmatic responses were significantly reduced using portable HEPA air cleaners in an environmental exposure chamber. This review provides a comprehensive overview of the current state of airborne Fel d 1 air filtration targeting the most efficient devices in cat allergen reduction. Novel emerging HEPA filters are targeting reduction of cat indoor asthma trigger so patient can might benefit from efficient solution.

Efficacy of air cleaners in asthmatics allergic to cat in ALYATEC® environmental exposure chamber

BACKGROUND

Air cleaners have been promoted for respiratory allergic disease prevention, but there is no clear clinical proof of their efficacy in allergic asthma.

OBJECTIVE

To examine the efficacy of a new air cleaner on early and late asthmatic responses in cat-allergic patients.

METHODS

This randomized, cross-over, double-blind placebo-controlled study enrolled 24 cat-asthmatic patients with GINA 1 asthma. At baseline, participants were exposed to 40 ng/m³ of airborne cat allergen for a maximum of 2 hours in ALYATEC^® environmental exposure chamber (EEC). All participants were subsequently randomized into two groups that were exposed to cat allergen, either with active then placebo air cleaners or with placebo then active air cleaners with a 3-week interval in the EEC. This study was registered under number (NCT03928561).

RESULTS

Fewer patients experienced an EAR with active air cleaners (seven patients; 29.17%) than placebo (21 patients; 87.50%). The response incidence was lower with active than with placebo air cleaners. A Cox model demonstrated a significant treatment effect (hazard ratio, 0.10; P = .002). Active air cleaners also prevented late asthmatic response: four patients (16.67%) had a late asthmatic response with active air cleaners compared to 11 patients (45.83%) with placebo (Prescott test P = .002). Active air cleaners also decreased the maximal severity of bronchial response (FEV1 decrease of 17.24% with active vs 25.62% with placebo air cleaners; P = .001).

CONCLUSIONS

Our present results demonstrated that Intense Pure Air XL^® air cleaners significantly prevented early and late asthmatic responses among cat-allergic asthmatics during cat allergen exposure in the ALYATEC^® EEC.

Immunological Factors Associated with Adult Asthma in the Aseer Region, Southwestern Saudi Arabia

Background: The prevalence of asthma is on the rise in Saudi Arabia. Data regarding the immunological profile of asthma in adults in the Aseer region, in southwestern Saudi Arabia, have not been well studied. Objectives: Our aim was to study the immunological factors associated with sensitization to asthma among adults in the Aseer region. Methods: A cross-sectional study with a nested case control design in a 1:1 ratio was conducted on a sample of adults attending primary health care centers in the Aseer region. The study used a validated Arabic version of the International study of asthma and allergies in childhood (ISAAC) questionnaire. The presence of wheezing in the past 12 months was used as a proxy for bronchial asthma. Matched age and sex controls were selected. Both groups were tested for complete blood count (CBC), total and differential white blood cell (WBC) count including eosinophils, total immunoglobulin E (IgE) measurement, allergen-specific immunoglobulin E (IgE), and cytokine levels. Results: The present study included 110 cases and 157 age- and sex-matched controls. Rye wheat was found to be a significant outdoor sensitizing agent ((odds ratio) OR = 5.23, 95% CI: 1.06–25.69). Indoors, house dust mites Dermatophagoides petronyssinus (OR = 2.04, 95% CI: 1.04–3.99) and Dermatophagoides farinae (OR = 2.50, 95% CI: 1.09–5.75) were significant. Higher total IgE (OR = 1.84, 95% CI: 1.10–3.06) and eosinophil levels (OR = 2.85, 95% CI: 1.14–7.15) were significantly associated with adult bronchial asthma in Aseer. On the other hand, the role of cytokines was not significant. Conclusions: In the present study, certain environmental agents were found to be important with regards to sensitization to bronchial asthma in adults. Knowledge about these sensitization agents should be disseminated to health providers and treating physicians in order to enhance preventive environmental control measures and asthma management. Asthma-treating physicians in the region should be alerted to the use of targeted biological therapies in selected asthmatics with difficult-to-control courses.

Thunderstorm-triggered asthma: what we know so far

Thunderstorm-triggered asthma (TA) is the occurrence of acute asthma attacks immediately following a thunderstorm. Epidemics have occurred across the world during pollen season and have the capacity to rapidly inundate a health care service, resulting in potentially catastrophic outcomes for patients. TA occurs when specific meteorological and aerobiological factors combine to affect predisposed patients. Thunderstorm outflows can concentrate aeroallergens, most commonly grass pollen in TA, at ground level to release respirable allergenic particles after rupture by osmotic shock related to humidity and rainfall. Inhalation of high concentrations of these aeroallergens by sensitized individuals can induce early asthmatic responses which are followed by a late inflammatory phase. Other environmental factors such as rapid temperature change and agricultural practices contribute to the causation of TA. The most lethal TA event occurred in Melbourne, Australia, in 2016. Studies on the affected individuals found TA to be associated with allergic rhinitis, ryegrass pollen sensitization, pre-existing asthma, poor adherence to inhaled corticosteroid preventer therapy, hospital admission for asthma in the previous year and outdoor location at the time of the storm. Patients without a prior history of asthma were also affected. These factors are important in extending our understanding of the etiology of TA and associated clinical indicators as well as possible biomarkers which may aid in predicting those at risk and thus those who should be targeted in prevention campaigns. Education on the importance of recognizing asthma symptoms, adherence to asthma treatment and controlling seasonal allergic rhinitis is vital in preventing TA. Consideration of allergen immunotherapy in selected patients may also mitigate risk of future TA. Epidemic TA events are predicted to increase in frequency and severity with climate change, and identifying susceptible patients and preventing poor outcomes is a key research and public health policy priority.

IgE sensitization in a cohort of adolescents in southern Sweden and its relation to allergic symptoms

Background

There is a strong and consistent association between IgE sensitization and allergy, wheeze, eczema and food hypersensitivity. These conditions are also found in non-sensitized humans, and sensitization is found among individuals without allergy-related diseases. The aim of this study was to analyse the sensitization profile in a representative sample of the population, and to relate patterns of allergens and allergen components to allergic symptoms.

Methods

A population of 195 adolescents took part in this clinical study, which included a self-reported questionnaire and in vitro IgE testing.

Results

Sensitization to airborne allergens was significantly more common than sensitization to food allergens, 43% vs. 14%, respectively. IgE response was significantly higher in airborne allergens among adolescents with rhinitis (p < 0.001) and eczema (p < 0.01). Among 53 children with allergic symptoms according to the questionnaire, 60% were sensitized. Sensitization to food allergens was found among those with rhinitis, but only to PR-10 proteins. None of the participants had IgE to seed storage proteins.

Conclusion

The adolescents in this study, taken from a normal Swedish population, were mainly sensitized to grass pollen and rarely to specific food allergens. The major grass pollen allergen Phl p 1 was the main sensitizer, followed by Cyn d 1 and Phl p 2. Sixty-one percent reporting any allergic symptom were sensitized, and the allergen components associated with wheeze and rhinoconjunctivitis were Fel d 4, Der f 2 and Can f 5.

Increasing specific immunoglobulin E levels correlate with the risk of anaphylaxis during an oral food challenge

BACKGROUND

Oral food challenges (OFCs) are necessary to diagnose food allergies; however, these tests can cause anaphylaxis. Higher specific immunoglobulin E (sIgE) levels to causative food have been associated with a positive OFC. To date, no data have been found to indicate the factors associated with severe symptoms or anaphylaxis among challenge-positive patients. This study aimed to clarify the association of sIgE with causative foods and anaphylaxis during OFC among the whole study population and challenge-positive patients.

METHODS

This cross-sectional study collected symptom and severity data between June 2012 and December 2016 during an open OFC to diagnose food allergy or confirm tolerance acquisition. We analyzed the risk factors for anaphylaxis during OFC.

RESULTS

A total of 2272 cases were analyzed (median age: 3.5 years; egg: 1166 cases; milk: 589 cases; wheat: 388 cases; and peanut: 129 cases). Among 979 challenge-positive patients, anaphylactic reactions were observed in 334 cases. A statistically significant association was observed between anaphylaxis during OFC and higher sIgE levels to causative foods (odds ratio: 2.71, 95% confidence interval: 1.94-3.78, for the third compared to the first tertile, P-value for trend <.001). Only gastrointestinal, respiratory, cardiovascular, and neurological symptoms were also statistically significantly associated with higher sIgE levels to causative foods.

CONCLUSIONS

The risk of all symptoms, except skin symptoms, during OFCs increased with increasing sIgE levels, and this consequently increased anaphylaxis during OFCs. The mechanism of how sIgE affects the prevalence of gastrointestinal, respiratory, cardiovascular, and neurological symptoms or anaphylaxis is unknown; thus, further study is required.

Dysbiosis of Inferior Turbinate Microbiota Is Associated with High Total IgE Levels in Patients with Allergic Rhinitis

Abnormalities in the human microbiota are associated with the etiology of allergic diseases. Although disease site-specific microbiota may be associated with disease pathophysiology, the role of the nasal microbiota is unclear. We sought to characterize the microbiota of the site of allergic rhinitis, the inferior turbinate, in subjects with allergic rhinitis (n = 20) and healthy controls (n = 12) and to examine the relationship of mucosal microbiota with disease occurrence, sensitized allergen number, and allergen-specific and total IgE levels. Microbial dysbiosis correlated significantly with total IgE levels representing combined allergic responses but not with disease occurrence, the number of sensitized allergens, or house dust mite allergen-specific IgE levels. Compared to the populations in individuals with low total IgE levels (group IgE^low), low microbial biodiversity with a high relative abundance of Firmicutes phylum (Staphylococcus aureus) and a low relative abundance of Actinobacteria phylum (Propionibacterium acnes) was observed in individuals with high total serum IgE levels (group IgE^high). Phylogeny-based microbial functional potential predicted by the 16S rRNA gene indicated an increase in signal transduction-related genes and a decrease in energy metabolism-related genes in group IgE^high as shown in the microbial features with atopic and/or inflammatory diseases. Thus, dysbiosis of the inferior turbinate mucosa microbiota, particularly an increase in S. aureus and a decrease in P. acnes, is linked to high total IgE levels in allergic rhinitis, suggesting that inferior turbinate microbiota may be affected by accumulated allergic responses against sensitized allergens and that site-specific microbial alterations play a potential role in disease pathophysiology.

Acute and chronic rhinosinusitis and allergic rhinitis in relation to comorbidity, ethnicity and environment

Background

This study was conducted to assess the effect of comorbidity, ethnicity, occupation, smoking and place of residence on allergic rhinitis (AR), acute rhinosinusitis (ARS) and chronic rhinosinusitis (CRS).

Methods

A GA²LEN (The Global Allergy and Asthma European Network) screening questionnaire was sent to a random sample of the Dutch population (n = 16700) in three different areas of the Netherlands.

Results

Fifty percent (8347) of the questionnaires sent were returned. A total of 29% respondents (27–31% in different areas) met the criteria for AR, 18% (17–21%) for ARS and 16% (13–18%) for CRS. Risk factors for AR were itchy rash, eczema, adverse response after taking a painkiller, asthma, CRS and ARS. Moreover, the risk of AR was twice as low for full-time housewives/househusbands than for people with jobs. The risk of ARS or CRS was significantly higher in respondents with a doctor’s diagnosis of CRS, AR, itchy rash or smoking. The risk of CRS was also significantly higher in respondents with an adverse response after taking painkillers, active smoking or asthma. Caucasians are generally less likely to have AR or CRS than Latin-Americans, Hindustani and African-Creoles, and more likely to have ARS than Asian, Hindustani, Mediterranean and African-Creoles.

Conclusions

This study found shared and distinct risk factors for AR, ARS and CRS and therefore provides support for the belief that they have shared symptoms but are different diseases with different aetiologies.

A Retrospective Study of Clinical Response Predictors in Subcutaneous Allergen Immunotherapy With House Dust Mites for Allergic Rhinitis

Purpose

House dust mites (HDM) are major allergens that cause allergic rhinitis (AR). Allergen-specific subcutaneous immunotherapy (SCIT) has been shown to be clinically beneficial in many clinical trials. Such trials, however, are not reflective of all patient populations. The aim of this study was to describe the efficacy and safety of SCIT in routine clinical practice in Korean adults with AR sensitized to HDM.

Methods

We reviewed medical records of 304 patients with AR treated at an allergy clinic of a tertiary hospital using SCIT with aluminum hydroxide-adsorbed allergen extract targeting HDM alone or with pollens for at least 1 year from 2000 to 2012. Patients with asthma were excluded. Rates of remission, defined as no further requirement of maintenance medication, over time were determined by means of life tables and extension of survival analysis. Specific immunoglobulin E (IgE) levels to HDM were categorized into 6 classes.

Results

The mean time until achieving remission was 4.9±0.1 years, and the cumulative incidence of remission from AR was 76.6%. Severe AR (odds ratio [OR], 0.40; 95% confidence interval [CI], 0.23-0.69; P=0.001), specific IgE levels to HDM ≥17.5 kU/L (OR, 1.85; 95% CI, 1.01-3.37; P=0.045), and duration of immunotherapy ≥3 years (OR, 7.37; 95% CI, 3.50-15.51; P<0.001) were identified as significant predictors of clinical remission during SCIT for patients with AR sensitized to HDM. Overall, 73 patients (24.0%) experienced adverse reactions to SCIT, and only 1 case of anaphylaxis (0.3%) developed.

Conclusions

SCIT with HDM was found to be effective and safe for patients with AR. Specific IgE levels to HDM and a duration of SCIT ≥3 years may be predictors of clinical responses to SCIT in AR patients.

Association between Allergies and Hypercholesterolemia: A Systematic Review

BACKGROUND

There is controversy in the literature regarding the potential relationship between atopic predisposition (AP) and serum cholesterol levels. To this purpose, we reviewed human studies that investigated this possible link.

METHODS

Following PRISMA guidelines, a literature search of PubMed and Science Direct for peer-reviewed journal articles in English from January 2003, with updates through to August 2016, was conducted. Relevant publications were reviewed that included pediatric and adult populations. Information on the study design, sample, intervention, comparators, outcome, time frame, and risk of bias were abstracted for each article.

RESULTS

Of 601 reviewed reports, 18 were included in this systematic review. Fifteen studies assessed the relationship between AP and serum cholesterol levels. Due to the lack both of observational and cross-sectional studies from the literature search at this time (only 8 studies also analyzed confounding factors) there is a high possibility of confounding variables (familial and genetic predisposition, age, gender, BMI, comorbidity, and medication status) that could not be ruled out.

CONCLUSION

Existing studies are heterogeneous, making it difficult to draw broad conclusions. Future studies and more detailed analyses, considering confounding variables and including a larger and homogeneous population, are needed to strengthen the argument for a link between lipid metabolism and atopy.

Allergic respiratory disease: Different allergens, different symptoms

BACKGROUND

Spanish population is rather homogeneous in its genetic and sociocultural characteristics, but allergen sensitization shows wide geographical variations. We aimed at assessing whether sensitization to different allergens in the diverse geographical areas induced different clinical and quality-of-life characteristics in adult patients with a first-time diagnosis of rhinitis and/or asthma.

METHODS

Two sequential, identically designed studies were carried out to evaluate such associations (PERFILAR I and II). PERFILAR II was an extension of PERFILAR I with additional allergens being included. Both phases were epidemiological, descriptive, cross-sectional, nonintervention multicenter studies. Participants were required to have lived for at least the last 2 years in the geographical zone. Asthma control assessment was based on ACQ-5. Health-related quality of life was evaluated with validated scales for rhinitis (ESPRINT-15) and asthma (Mini-AQLQ). Skin prick tests were used to identify sensitization to involved allergens.

RESULTS

A total of 301 physicians recruited 2711 patients for PERFILAR I+II. Sensitization to allergens was significantly different in patients with rhinitis with/without asthma. Seasonal allergens were associated with rhinitis, a longer time to asthma development, and more severe and commonly intermittent rhinitis. HDM were associated with more common rhinitis, and Alternaria was associated with asthma. The study confirms an association of geographical areas with relevant allergens and allergic clinical picture.

CONCLUSION

Different types of aeroallergens and specific sensitization profiles are associated with different allergic clinical pictures (rhinitis with/without asthma), different clinical symptoms, and different levels of severity. This could have implications to predict later clinical course and to select appropriate management approaches.

Occupational Respiratory Allergic Diseases in Healthcare Workers

Healthcare workers (HCWs) are exposed to a range of high and low molecular weight agents that are allergic sensitizers or irritants including cleaners and disinfectants, natural rubber latex, and various medications. Studies have shown that exposed HCWs are at risk for work-related rhinitis and asthma (WRA). Work-related rhinitis may precede development of WRA and should be considered as an early marker of WRA. Avoidance of causative exposures through control strategies such as elimination, substitution, engineering controls, and process modification is the preferred primary prevention strategy for preventing development of work-related allergic diseases. There is limited evidence for the effectiveness of respirators in preventing occupational asthma. If sensitizer-induced WRA is diagnosed, it is important to avoid further exposure to the causative agent, preferably by more rigorous application of exposure control strategies to the workplace. This review focuses on allergic occupational respiratory diseases in HCWs.

Different clinical effect of several types of airborne allergens on the severity of bronchial hyperreactivity

BACKGROUND

Atopic sensitization belongs to the most common risk factors for bronchial asthma. However, in clinical practice, it is not clear whether sensitization against pollen and perennial allergens is differently associated with the severity of bronchial hyperresponsiveness (BHR).

AIM

To find out whether patients sensitized to perennial allergens differ in severity of bronchial hyperresponsiveness from patients sensitized to pollen allergens.

METHODS

The study includes 109 patients. Based on the results of skin prick tests, patients were divided into three groups: sensitivity to pollen allergens - group A; sensitivity to perennial allergens - group B; sensitivity to both pollen and perennial allergens - group C. Based on the histamine bronchoprovocation test, we compared the values of histamine provocative concentration causing a 20% drop in FEV₁ (PC₂₀) among particular groups of patients. Mild bronchial hyperresponsiveness was determined if the value of PC₂₀ was >4 mg/ml, while if the value of PC₂₀ was <4 mg/ml, the bronchial hyperresponsiveness was considered as moderate/severe.

RESULTS

A statistically significant difference was found in the degrees of bronchial hyperresponsiveness between the three groups of patients, namely, group A with the patients sensitized only to the pollen allergens, group B comprising patients sensitized to the perennial allergens only, and group C, involving patients sensitized to the combination of both pollen and perennial allergens. The PC₂₀ values were higher among the patients from the group A (7.46 mg/ml) compared to group B (4.25 mg/ml) and C (4.52 mg/ml). The odds ratio for moderate/severe BHR was 5.21 and 5.04 in group B and group C, respectively.

CONCLUSION

Severity of bronchial hyperresponsiveness shows differences according to sensitization to particular allergens. Perennial allergens are more often associated with serious forms of bronchial hyperresponsiveness which also have an impact on the severity and prognosis of bronchial asthma.

The Clinical Impact of Bet v 6 in Birch Pollen-Sensitized Patients

BACKGROUND

Bet v 6, a minor birch pollen allergen, is commercially available for allergen-specific IgE antibody testing. However, there is hardly any literature on the clinical impact of Bet v 6. The aim of the present study was to analyze if testing specific IgE against Bet v 6 can add valuable benefit to the standard diagnostics of birch pollen-sensitized patients, especially in patients with unknown sensitization-eliciting allergens.

METHODS

Birch pollen-sensitized patients with missing IgE reactivity against Bet v 1, 2, and 4 were tested for specific IgE antibodies against Bet v 6. For comparison, an equal number of randomly selected patients with birch pollen sensitization, regardless of their individual sensitization patterns, were tested for specific anti-Bet v 6.

RESULTS

Of 57 cases with missing reactivity against the standard birch pollen allergens, 2 patients were positive for Bet v 6. In the representative sample, 3 patients showed specific IgE against Bet v 6 - resulting in a total prevalence of 5%. None of the Bet v 6-positive patients showed allergic symptoms after exposure to birch pollen or an oral allergy syndrome. An increased prevalence of asthma and a higher degree of sensitization were the only distinctive clinical features in Bet v 6-positive patients.

CONCLUSIONS

Among birch pollen-sensitized patients, the prevalence of specific IgE against Bet v 6 is low. Further, sensitization to Bet v 6, which shows characteristics of a panallergen, remains clinically silent. Therefore, determination of anti-Bet v 6 is not considered useful in the clinical routine.

Cross-sectional study on allergic sensitization of Austrian adolescents using molecule-based IgE profiling

BACKGROUND

Allergen-specific IgE antibodies are a hallmark of type I allergy. The aim of this cross-sectional study was to analyze the sensitization profiles of an Austrian adolescent population utilizing molecule-based IgE diagnosis.

METHODS

Serum samples of 501 nonselected pupils from Salzburg, Austria, were tested in ImmunoCAP ISAC^® for IgE reactivity to 112 single allergens. Sensitization profiles were assessed and statistically coordinated with reported allergies.

RESULTS

In the population aged 12-21 years, 53.5% showed IgE reactivity to at least one allergen tested. The highest prevalence was found for Phl p 1 from grass pollen (26.5%), group 2 mite allergens (18.2%), Bet v 1 from birch pollen (16.3%) and Fel d 1 from cat (14.4%). The majority of participants showed a complex sensitization profile and reacted on average to 9 allergens. Pollen sensitization was highly prevalent (41.7%) and mainly driven by group I grass and PR-10 allergens of the Betulaceae family, while Pla l 1 represented the most relevant weed. Diagnosed and self-reported allergies were noted in 21.9% and 45.5% of participants, respectively, and correlated well with in vitro results. Among atopic individuals, 71.4% reported to suffer from at least one allergy; concordance was found for grass and cat sensitization, while venom- and weed pollen-positive individuals were frequently asymptomatic.

CONCLUSIONS

More than half of the tested adolescent population had already established an atopic status presenting a complex IgE reactivity profile dominated by pollen sensitization. Detailed molecule-based analysis allows determining relevant biomarkers and monitoring of the atopic status in populations.

IgE-associated allergic disorders: recent advances in etiology, diagnosis, and treatment

IgE-associated allergic diseases belong to the most common inflammatory conditions. Their clinical manifestation ranges from mild symptoms to life-threatening episodes. Often patients experience a reduction in physical and psychologic well-being and suffer from a decreased quality of life due to disease activity. The continuously rising number of people that are affected by an allergic condition indicates an urgent need for better diagnostics and more efficient treatment options. Recent progress in the understanding of pathophysiologic mechanisms underlying IgE-associated allergic disorders has led to the identification of novel therapeutic targets and the development of drug candidates that are currently under evaluation. In this review, we highlight studies and clinical trials, which have helped to gain further insight in the etiology of IgE-associated allergic conditions as well as advances in the development of diagnostic tools and therapeutic approaches recently published in Allergy (European Journal of Allergy and Clinical Immunology).

A clear urban-rural gradient of allergic rhinitis in a population-based study in Northern Europe

BACKGROUND

The protective effect of farm upbringing on allergic rhinitis is well known, but how upbringing in other environments influences the development of allergic rhinitis is scarcely investigated. The aim of this study was to investigate the association between place of upbringing and pet keeping in childhood and allergic rhinitis and nasal symptoms in adulthood.

METHODS

The population-based Respiratory Health in Northern Europe study includes subjects from Denmark, Norway, Sweden, Iceland, and Estonia born in 1945-1973. This paper analyses 13,376 participants of the third study wave. Six categories of place of upbringing were defined: farm with livestock, farm without livestock, village in rural area, small town, city suburb, and inner city. Pets in the home at birth and during childhood were recorded. Data were analysed using adjusted logistic regression models.

RESULTS

Livestock farm upbringing predicted less adult allergic rhinitis [odds ratio (OR) 0.68, 0.54-0.85] and nasal symptoms (OR 0.82, 0.68-0.99) than city upbringing, and an urban-rural gradient with decreasing risk per level of urbanisation was observed (OR 0.92, 0.88-0.94). Pets in the home at birth (OR 0.78, 0.68-0.88) and during childhood (OR 0.83, 0.74-0.93) were associated with less subsequent allergic rhinitis. Pet keeping did not explain the protective effect of place of upbringing.

CONCLUSION

Risk of allergic rhinitis and nasal symptoms in adulthood was inversely associated with the level of urbanisation during upbringing. Pets at birth decreased the risk further, but did not explain the urban-rural gradient. Persistent beneficial effects of microbial diversity in early life might be an explanation for the findings.

"Cumulative Stress": The Effects of Maternal and Neonatal Oxidative Stress and Oxidative Stress-Inducible Genes on Programming of Atopy

Although extensive epidemiological and laboratory studies have been performed to identify the environmental and immunological causes of atopy, genetic predisposition seems to be the biggest risk factor for allergic diseases. The onset of atopic diseases may be the result of heritable changes of gene expression, without any alteration in DNA sequences occurring in response to early environmental stimuli. Findings suggest that the establishment of a peculiar epigenetic pattern may also be generated by oxidative stress (OS) and perpetuated by the activation of OS-related genes. Analyzing the role of maternal and neonatal oxidative stress and oxidative stress-inducible genes, the purpose of this review was to summarize what is known about the relationship between maternal and neonatal OS-related genes and the development of atopic diseases.

How to manage a child with difficult asthma?

INTRODUCTION

Children with difficult asthma have significant morbidity and fail to achieve asthma control despite being prescribed high dose maintenance treatment. If control remains poor after diagnostic confirmation, detailed assessments of the reasons for asthma being difficult-to-control are needed. Underlying modifiable factors including non-adherence to medication, persistent environmental exposures that trigger asthma symptoms and psychosocial factors contribute to poor control in these patients.

AREAS COVERED

The focus of this review is to provide a practical approach to the diagnosis and management of difficult asthma including an overview of long term assessments to identify potential progression to true, severe asthma. A multi-disciplinary team is critical to enable modifiable factors to be identified and addressed. Significant resources are required to manage paediatric difficult asthma optimally and only specialist centres should be tasked with the assessment of these patients. Although this may have an impact on healthcare resources, long term benefits for lung health are significant. Expert commentary: The management of paediatric difficult asthma is not simple and involves numerous professionals with varied expertise. However, if it is not undertaken with the appropriate skills, there is a significant risk of children receiving inappropriate invasive investigations and therapies that will have no impact on morbidity.