Asthma related to Alternaria sensitization: an analysis of skin-test and serum-specific IgE efficiency based on the bronchial provocation test

Factors associated with aeroallergen testing among adults with asthma in a large health system

Background

Aeroallergen testing informs precision care for adults with asthma, yet the epidemiology of testing in this population remains poorly understood.

Objective

We sought to identify factors associated with receiving aeroallergen testing, the results of these tests, and subsequent reductions in exacerbation measures among adults with asthma.

Methods

We used electronic health record data to conduct a retrospective, observational cohort study of 30,775 adults with asthma who had an office visit with a primary care provider or an asthma specialist from January 1, 2017, to August 26, 2022. We used regression models to identify (1) factors associated with receiving any aeroallergen test and tests to 9 allergen categories after the index visit, (2) factors associated with positive test results, and (3) reductions in asthma exacerbation measures in the year after testing compared with before testing.

Results

Testing was received by 2201 patients (7.2%). According to multivariable models, receiving testing was associated with having any office visit with an allergy/immunology specialist during the study period (odds ratio [OR] = 91.3 vs primary care only [P < .001]) and having an asthma emergency department visit (OR = 1.62 [P = .004]) or hospitalization (OR = 1.62 [P = .03]) in the year before the index visit. Age 65 years or older conferred decreased odds of testing (OR = 0.74 vs age 18-34 years [P = .008]) and negative test results to 6 categories (P ≤ .04 for all comparisons). Black race conferred increased odds of testing (OR =1.22 vs White race [P = .01]) and positive test results to 8 categories (P < .04 for all comparisons). Exacerbation measures decreased after testing.

Conclusion

Aeroallergen testing was performed infrequently among adults with asthma and was associated with reductions in asthma exacerbation measures.

[Allergy Diagnostics 2021]

Allergic diseases are among the most common diseases worldwide. For appropriate management knowledge of the allergy trigger is crucial. The clinical picture of allergic diseases is diverse and correct diagnosis is often a challenge. The allergist needs to distinguish intolerances from allergies and infectious diseases from non-infectious triggers. Test results have to be interpreted accordingly to differentiate sensitizations from allergies. In this review current state of the art diagnostic measures to diagnose type I and type IV allergies are described and discussed.Immediate type allergies such as allergic rhinoconjunctivitis, asthma and anaphylaxis are mediated by allergen-specific IgE antibodies detectable both in serum and tissue. Typical triggers are pollen, mites, animal epithelia, food, insect toxins and pharmaceuticals. In everyday practice, diagnostics are based on three complementary pillars: the allergy-specific anamnesis as a prerequisite of correct interpretation of subsequent diagnostic tests like skin testing and serological immunoglobulin detection. These can be supplemented as required and available by provocation tests to prove clinical reactivity and cellular assays to demonstrate the cellular immune response.Type IV allergic reactions are mediated by T cells causing contact allergy with a local eczematous reaction with a latency of several hours to days. Some 3,500 triggers, often from occupational environment, are known; e. g., nickel, chromium, cobalt, fragrances, rubber, plastics, preservatives, dyes, neomycin, benzocaine, sulfonamides, quinidine, wool wax, perubalsam, eye therapeutics, light filter substances, disinfectants, pesticides, technical oils or plants. Diagnosis of contact allergy combines the history of cutaneous exposure with associated symptoms and patch testing, with detection of a late phase clinical reaction after 6 to 48, up to a maximum of 96 hours after antigen contact.

The impact of fungal allergic sensitization on asthma

PURPOSE OF REVIEW

Fungal sensitization may contribute to the development of asthma as well as asthma severity. The purpose of this review is to summarize existing knowledge about the pathophysiology, diagnosis, and management of fungal sensitization in asthma and highlight unmet needs and target areas for future investigation.

RECENT FINDINGS

Fungal sensitization may occur by a normal or aberrant immune response. Allergic sensitization to fungi is mediated by the adaptive immune response driven by TH2 cells and the innate immune response driven by the innate lymphoid cells group 2. Diagnosis of fungal sensitization can be made by either skin prick testing or measurement of fungal-specific serum IgE. Fungal sensitization in asthma has been associated with worse disease severity, including reduced lung function, increased risk of hospitalizations, and life-threatening asthma. A spectrum of disease related to fungal sensitization has been described in asthma including allergic bronchopulmonary mycosis and severe asthma with fungal sensitization (SAFS). The role of antifungals and targeted biologic therapy in asthma with fungal sensitization need further investigation.

SUMMARY

There is increasing awareness of the contribution of fungal sensitization to asthma severity. However, there are no therapies with proven efficacy. Randomized clinical trials are needed to further investigate the role of biologics.

Microbiome and antibiotic resistome in household dust from Beijing, China

We spend ever-increasing time indoors along with urbanization; however, the geographical distribution patterns of microbiome and antibiotic resistome, and their driving forces in household environment remains poorly characterized. Here, we surveyed the bacterial and fungal communities, and the resistome in settled dust gathered from 82 homes located across Beijing, China, employing Illumina sequencing and high-throughput quantitative PCR techniques. There was no clear geographical distribution pattern in dust-related bacterial communities although a slight but significant (P < 0.05) distance-decay relationship occurred in its community similarity; by contrast, a relatively distinct geographical clustering and a stronger distance-decay relationship were observed in fungal communities at the local scale. The cross-domain (bacteria versus fungi) relationships in the microbiome of the dust samples were mostly observed as robust co-occurrence correlations. The bacterial communities were dominated by Proteobacteria and Actinobacteria phyla, with human skin, soil and plants being potential major sources. The fungal communities largely comprised potential allergens (a median 61% of the fungal sequences), with Alternaria genus within Ascomycota phylum being the most predominant taxa. The profile of dust-related bacterial communities was mainly affected by housing factors related to occupants and houseplants, while that of fungal communities was determined by georeferenced environmental factors, particularly vascular plant diversity. Additionally, a great diversity (1.96 on average for Shannon index) and normalized abundance (2.22 copies per bacterial cell on average) of antibiotic resistance genes were detected across the dust samples, with the dominance of genes resistant to vancomycin and Macrolide-Lincosamide-Streptogramin B. The resistome profile exhibited no distinct geographical pattern, and was primarily driven by certain bacterial phyla and occupancy-related factors. Overall, we underline the significance of anthropogenic impacts and house location in structuring bacterial and fungal communities inside homes, respectively, and suggest that household dust is an overlooked reservoir for antibiotic resistance.

Gene profiling and expression of major allergen Alt a 1 in Alternaria alternata and related members of the Pleosporaceae family

BACKGROUND

Members of the Pleosporaceae family are known as important sources of airborne allergens which are responsible for asthma and allergic diseases.

AIMS

The purpose of this study was to investigate the gene profiling and expression pattern of Alt a 1 in Alternaria alternata and other members of the Pleosporaceae family including Stemphylium botryosum, Ulocladium chartarum, Curvularia lunata, Cladosporium cladosporioides, and Epicoccum nigrum.

METHODS

Alternaria alternata and related genera were cultured on Czapek-Dox broth medium at 25°C for 21 days. The presence of Alt a 1 was assessed in fungal culture filtrates by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and then confirmed by immunoblot analysis. Real-time PCR was carried out for quantitation of the Alt a 1 gene encoding corresponding protein at the transcriptional level using cDNA prepared from fungal RNA.

RESULTS

SDS-PAGE showed protein bands ranging from 14 to 100kDa. A 14kDa band corresponding to Alt a 1 was present in A. alternata, S. botryosum and U. chartarum. The gene expression of Alt a 1 was reported in A. alternata and some other related genera. The C_t mean value recorded for A. alternata strains ranged from 24.70 to 27.84 while it was in the range 23.62-32.09 for other related taxa. No apparent transcription or expression was revealed in C. cladosporioides.

CONCLUSIONS

The presence and efficient expression of Alt a 1 gene in A. alternata and other related taxa indicate that Alt a 1 protein is a major component of the secretory machinery of Pleosporaceae family members, and it may play a crucial role in its allergenicity.

Performance of specific immunoglobulin E tests for diagnosing occupational asthma: a systematic review and meta-analysis

OBJECTIVES

To determine the test performance parameters for the retrievable range of high-molecular-weight (HMW) and low-molecular-weight (LMW) occupational allergens and to evaluate the impact of allergenic components and the implementation of measures for test validation.

METHODS

A protocol with predefined objectives and inclusion criteria was the basis of an electronic literature search of MEDLINE and EMBASE (time period 1967-2016). The specific inhalation challenge and serial peak flow measurements were the reference standards for the specific IgE (sIgE) test parameters. All of the review procedures were reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

Seventy-one studies were selected, and 62 entered meta-analysis. Pooled pairs analysis indicated a sensitivity of 0.74(95% CI 0.66 to 0.80) and specificity of 0.71(95% CI 0.63 to 0.77) for HMW allergens and a sensitivity of 0.28(95% CI 0.18 to 0.40) and specificity of 0.89(95% CI 0.77 to 0.95) for LMW allergens. Component-specific analysis improved the test parameters for some allergens. Test validation was handled heterogeneously among studies.

CONCLUSION

sIgE test performance is rather satisfactory for a wide range of HMW allergens with the potential for component-specific approaches, whereas sensitivity for LMW allergens is considerably lower, indicating methodological complications and/or divergent pathomechanisms. A common standard for test validation is needed.

Does allergy explain why some children have severe asthma?

Asthma is a common disease in childhood with a minority of affected children having severe therapy-resistant asthma (STRA). Children with STRA can be differentiated from those with mild-moderate disease by greater allergic sensitization, increased eosinophilic airway inflammation, increased airway remodelling and reduced corticosteroid responsiveness. The aetiology of STRA in children is multifactorial but allergy seems to play a key role. Many children with asthma have coexisting allergic disease, and severe rhinitis seems to be an important driver of STRA in children. Allergies to foods, moulds, pollen and pets have also been associated with severe asthma exacerbations. Identifying allergens that are driving asthma symptoms in children with STRA may provide additional strategies for improving their disease control. Avoidance strategies may be possible. Additional monoclonal antibody therapy with Omalizumab or Mepolizumab may be helpful in children with clinically important polysensitization.

Early life risk factors for chronic sinusitis: A longitudinal birth cohort study

BACKGROUND

Chronic sinusitis is a commonly diagnosed condition in adults who frequently present with late-stage disease and irreversible changes to the sinus mucosa. Understanding the natural history of chronic sinusitis is critical in developing therapies designed to prevent or slow the progression of disease.

OBJECTIVE

We sought to determine early life risk factors for adult sinusitis in a longitudinal cohort study (Tucson Children's Respiratory Study).

METHODS

Physician-diagnosed sinusitis was reported at age 6. Adult sinusitis between 22 and 32 years was defined as self-reported sinusitis plus physician-ordered sinus radiologic films. Atopy was assessed by skin prick test. Individuals were grouped into 4 phenotypes: no sinusitis (n = 621), transient childhood sinusitis only (n = 57), late-onset adult sinusitis only (n = 68), and early onset chronic sinusitis (childhood and adult sinusitis, n = 26).

RESULTS

Sinusitis was present in 10.8% of children and 12.2% of adults. Childhood sinusitis was the strongest independent risk factor for adult sinusitis (odds ratio = 4.2; 95% CI: 2.5-7.1; P < .0001; n = 772). Early onset chronic sinusitis was associated with increased serum IgE levels as early as at 9 months of age, atopy (assessed by skin prick test reactivity), childhood eczema and allergic rhinitis, frequent childhood colds, maternal asthma, and with increased prevalence of concurrent asthma. No association was found between late-onset adult sinusitis and any of the early life risk factors studied.

CONCLUSIONS

We identified an early onset chronic sinusitis phenotype associated with a predisposition to viral infections/colds in early life, allergies, and asthma. Elucidation of the molecular mechanisms for this phenotype may lead to future therapies to prevent the progression of the disease into adult sinusitis.

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.

Diagnosing environmental allergies: Comparison of skin-prick, intradermal, and serum specific immunoglobulin E testing

Background:

Allergists commonly perform intradermal skin testing (IDST) after negative skin-prick testing (SPT) to comprehensively diagnose environmental allergic sensitization. However, with the availability of modern methods to detect serum-specific immunoglobulin E (ssIgE), it is unclear if ssIgE testing could substitute for IDST.

Objective:

To determine the efficacy of ssIgE testing and IDST when added to SPT in diagnosing environmental allergic sensitizations.

Methods:

SPT, IDST, and ssIgE testing to nine common environmental allergens were analyzed in 75 patients with oculonasal symptoms who presented to our allergy clinics in the Bronx, New York, between January 2014 and May 2015.

Results:

A total of 651 SPT and 499 ssIgE tests were independently performed and revealed 162 (25%) and 127 (25%) sensitizations, respectively. When SPT results were negative, IDST results revealed 108 of 452 additional sensitizations (24%). In contrast, when SPT results were negative, ssIgE test results only revealed 9% additional sensitizations. When both SPT and IDST results were negative, ssIgE testing only detected 3% of additional sensitizations, and ssIgE levels were typically low in these cases (median, 1.25 kU/L; range, 0.357–4.47 kU/L). When both SPT and ssIgE test results were negative, IDST results detected 15% additional sensitizations.

Conclusion:

IDST detected more additional environmental sensitizations compared with ssIgE testing. IDST, therefore, may be useful when the SPT and/or ssIgE testing results were negative, but the exposure history indicated relevant allergic sensitization. Serology added only a little more information if both SPT and IDST results were negative but may be useful in combination with SPT if IDST cannot be performed.

Ambient Air Pollution, Meteorological Factors and Outpatient Visits for Eczema in Shanghai, China: A Time-Series Analysis

Environmental irritants are important risk factors for skin diseases, but little is known about the influence of environmental factors on eczema incidence. In this time-series study, our objective was to examine the associations of environmental factors with outpatient visits for eczema. Daily outpatient visits between 2007 and 2011 (1826 days) were collected from Huashan Hospital in Shanghai, China. We used an overdispersed generalized additive model to investigate the short-term association between environmental factors and outpatient visits for eczema. Daily outpatient visits for eczema were significantly associated with air pollution and meteorological factors. For example, a 10 μg/m³ increase of 7-day (lag 06) average concentrations of PM₁₀ (particulate matter no greater than 10 microns), SO₂, NO₂ was associated with 0.81% (95% confidence intervals (CI) 0.39%, 1.22%), 2.22% (95% CI: 1.27%, 3.16%) and 2.31% (95% CI: 1.17%, 3.45%) increase in outpatient visits for eczema, respectively. A 10 °C elevation of temperature on lag 0 day were associated with 8.44% (95% CI: 4.66%, 12.22%) increase in eczema visits, whereas 10 unit decrease of 7-day average relative humidity were associated with 10.86% (95% CI: 8.83%, 12.89%) increase in eczema visits. This study provided clear evidence of ambient air pollution, high temperature and low relative humidity on increasing the incidence of eczema in Shanghai, China.

Exposure to ambient bioaerosols is associated with allergic skin diseases in Greater Taipei residents

Allergic skin diseases may result from various types of chemical and biological allergens. This study investigated the association between ambient bioaerosol exposure and allergic skin diseases by using the exposure data obtained from land use regression models and interpolated data. Data on daily average outpatient visits for atopic dermatitis (ICD-9-CM 691.8) and contact dermatitis and other eczema (ICD-9-CM 692.9) between November 2011 and August 2012 were obtained from the National Health Insurance Research Database. A generalized estimating equation was used to analyze the associations between the skin diseases and ambient bioaerosol levels. The results indicated that during the study period, contact dermatitis and other eczema were more prevalent than atopic dermatitis in the study area. Most cases were observed in districts of Taipei City and 3 major districts of New Taipei City, namely Xinzhuang, Banqiao, and Xindian. In univariate analysis, most bioaerosols were positively associated with both skin diseases. After adjustment for air pollution and sociodemographic factors, exposure to total fungal spores was significantly associated with atopic dermatitis in males (relative risk [RR] = 1.12; 95% confidence interval [CI] = 1.05-1.19). Contact dermatitis and other eczema had significant relationships with Cladosporium in males (RR = 1.07; 95% CI = 1.02-1.14) and with Aspergillus/Penicillium in females (RR = 1.04; 95% CI = 1.02-1.07). Meteorological parameters, namely wind speed, temperature, and rainfall, were also significantly associated with skin diseases. Our findings reveal that exposure to ambient bioaerosols is a significant and independent risk factor for allergic skin diseases.

How to diagnose mould allergy? Comparison of skin prick tests with specific IgE results

BACKGROUND

Diagnosis of mould allergy is complicated due to the heterogeneity of the test material and the decrease in the number of commercial mould skin test solutions that are currently available.

OBJECTIVES

The aim of this study was to compare skin prick tests (SPT) from different manufacturers to one another and concurrently with sIgE tests for Aspergillus fumigatus (Asp f), Cladosporium herbarum (Cla h), Penicillium chrysogenum (Pen ch), Alternaria alternata (Alt a) and Aspergillus versicolor (Asp v) to ascertain a feasible diagnostic procedure for mould sensitization.

METHODS

In this multi-centre study, 168 patients with mould exposure and/or mould-induced respiratory symptoms were included. Mould SPT solutions were analysed biochemically and tested in duplicate on patients' arms. Specific IgE (sIgE) concentrations to corresponding mould species and mould mix (mx1) were measured by ImmunoCAP. SPTs in accordance with one another and with sIgE were further considered. The test efficiency was calculated using receiver-operating characteristic (ROC) analysis.

RESULTS

Mould sensitization was more frequently detected by the SPT (90 of 168) than by the sIgE tests (56 of 168). Concordances of double SPT positives were only sufficient (≥ 80%) for environmental allergens, two Asp f and three Alt a SPT solutions, whereas all other mould solutions revealed concordances < 80%. The antigen content of SPT solutions was positively associated with concordant SPT double values as well as with sIgE. Taking sIgE as the 'positive standard', all mould SPT solutions revealed test efficiencies > 80%, but varied up to 20% in sensitivity and positive predictive value with the exception of Alt a.

CONCLUSIONS

SPT solutions are sensitive and essential diagnostic tools for the detection of mould sensitization. Our recommendation for diagnosis would be to test at least Alt a, Asp f and Pen ch using SPT and additional sIgE test to mx1.

Clinical Evaluation and Management of Patients with Suspected Fungus Sensitivity

Fungus-sensitized patients usually present with symptoms that are similar to symptoms presented by those who are sensitized to other aeroallergens. Therefore, diagnosis and management should follow the same pathways used for patients with allergic conditions in general. The physician should consider that a relationship between fungal exposure and symptoms is not necessarily caused by an IgE-mediated mechanism, even when specific fungal IgE is detected. Until recently, IgE-mediated allergy has been documented only for a limited number of fungi. We propose a series of questions to be used to identify symptoms that occur in situations with high fungal exposure and a limited skin-prick-test panel (Alternaria, Cladosporium, Penicillium, Aspergillus, Candida) that can be amplified only in cases of high suspicion of other fungal exposure (eg, postfloods). We also review in vitro testing for fungi-specific IgE. Treatment includes environmental control, medical management, and, when appropriate, specific immunotherapy. Low-quality evidence exists supporting the use of subcutaneous immunotherapy for Alternaria to treat allergic rhinitis and asthma, and very low quality evidence supports the use of subcutaneous immunotherapy for Cladosporium and sublingual immunotherapy for Alternaria. As is the case for many allergens, evidence for immunotherapy with other fungal extracts is lacking. The so-called toxic mold syndrome is also briefly discussed.

Sensitization to fungal allergens: Resolved and unresolved issues

Exposure and sensitization to fungal allergens can promote the development and worsening of allergic diseases. Although numerous species of fungi have been associated with allergic diseases in the literature, the significance of fungi from the genera Alternaria, Cladosporium, Penicillium, Aspergillus, and Malassezia has been well documented. However, it should be emphasized that the contribution of different fungal allergens to allergic diseases is not identical, but species-specific. Alternaria and Cladosporium species are considered to be important outdoor allergens, and sensitization and exposure to species of these genera is related to the development of asthma and rhinitis, as well as epidemics of asthma exacerbation, including life-threatening asthma exacerbation. In contrast, xerophilic species of Penicillium and Aspergillus, excluding Aspergillus fumigatus, are implicated in allergic diseases as indoor allergens. A. fumigatus has a high capacity to colonize the bronchial tract of asthmatic patients, causing severe persistent asthma and low lung function, and sometimes leading to allergic bronchopulmonary aspergillosis. Malassezia are common commensals of healthy skin, although they are also associated with atopic dermatitis, especially on the head and neck, but not with respiratory allergies. Despite its importance in the management of allergic diseases, precise recognition of species-specific IgE sensitization to fungal allergens is often challenging because the majority of fungal extracts exhibit broad cross-reactivity with taxonomically unrelated fungi. Recent progress in gene technology has contributed to the identification of specific and cross-reactive allergen components from different fungal sources. However, data demonstrating the clinical relevance of IgE reactivity to these allergen components are still insufficient.

Skin testing versus serum-specific IgE testing: which is better for diagnosing aeroallergen sensitization and predicting clinical allergy?

An accurate diagnosis of aeroallergen sensitization is pivotal to clinical practice and research. Given the recent technological advances in analyzing serum allergen-specific IgE, the question of which testing method, skin or serum testing, is superior in diagnosing allergic sensitization must be readdressed, as well as their value in predicting clinical disease. This review article provides a detailed summary of recent studies addressing these questions. Conclusively, most studies show substantial discordance between serum-specific IgE and skin testing results, suggesting that the two testing methods compliment each other and cannot be used interchangeably. On average, using only one testing method may misdiagnose every fourth allergically sensitized patient as non-sensitized. In addition, depending on the allergen tested, skin prick testing and serum-specific IgE testing appear to be the methods of choice in predicting outcomes of experimental allergen challenge, while intradermal testing is less contributory.

Developments in the field of allergy in 2011 through the eyes of Clinical and Experimental Allergy

As in previous years, we felt it would be of value to our readership to summarize the new information provided by the authors who have published in Clinical and Experimental Allergy in 2011 and set this in the context of recent advances in our understanding of the pathogenesis and management of allergic disease in all its many manifestations. In 2011, about 210 articles were published in Clinical and Experimental Allergy including editorials, reviews, opinion articles, guidelines, letters, book reviews and of course at the heart of the journal, papers containing original data. As before, this review is divided into sections based on the way the journal is structured, although this year we have grouped together all the papers dealing with mechanisms of allergic disease, whether they involve patients (clinical mechanisms), pure in vitro studies (basic mechanisms) or animal models (experimental models), as we felt this was a more coherent way to deal with the subject. In the field of asthma and rhinitis, the relationship between airway inflammation and airway dysfunction was of perennial interest to investigators, as were phenotypes and biomarkers. Aspirin hypersensitivity appeared in studies in several papers and there was new interest in asthma in the elderly. The mechanisms involved in allergic disease describe advances in our understanding of T cell responses, the relationship between inflammation and disease, mast cell and basophil activation, steroid resistance and novel therapies. In the section dealing with epidemiology, studies seeking to identify risk factors for allergic disease including vitamin D are prominent, as once again are studies investigating gene-environment interactions. The clinical allergy section focuses on drug allergy, food allergy and immunotherapy. The area of oral immunotherapy for food allergy is well covered and we were grateful to Stephen Durham for guest editing an outstanding special issue on immunotherapy in the centenary year of Leonard Noon's pioneering work. Lastly, in the field of allergens, the interest in component-resolved diagnosis continues to grow and there are also articles describing important novel cultivars and the effect of food processing on the allergenic properties of foods. Another terrific year, full of important and high-quality work,which the journal has been proud to bring to the allergy community.

Specific IgE levels to Dermatophagoides pteronyssinus are associated with meteorological factors

BACKGROUND

Dermatophagoides pteronyssinus specific IgE (sIgE) measurement is a major diagnostic test for the detection of sensitization to that allergen.

METHODS

To investigate the effect of climate on the seasonal variations of D.pteronyssinus sIgE, we studied the tests performed in an insular population during a 10-year period. The association with meteorological factors was evaluated with multiple regression analyses.

RESULTS

Of 24,879 tests performed for D. pteronyssinus sIgE, 16,719 (67.2%) were D. pteronyssinus sIgE positive; 24.5% were tested for asthma and 46.07% for rhinitis. D. pteronyssinus sIgE levels showed a seasonal pattern with an annual peak in November. In the multivariate analyses solar radiation (r = -0.94) and relative humidity (r = 0.86) were independent factors associated with D. pteronyssinus sIgE levels. The resulting model could explain 93% (p < 0.001) of D. pteronyssinus sIgE variability.

CONCLUSIONS

Our population showed a seasonal pattern of D. pteronyssinus sIgE explained by relative humidity and solar radiation.

Alternaria alternata allergen Alt a 1: a unique β-barrel protein dimer found exclusively in fungi

BACKGROUND

Alternaria species is one of the most common molds associated with allergic diseases, and 80% of Alternaria species-sensitive patients produce IgE antibodies to a major protein allergen, Alt a 1. The structure and function of Alt a 1 is unknown.

OBJECTIVE

We sought to obtain a high-resolution structure of Alt a 1 using x-ray crystallography and to investigate structural relationships between Alt a 1 and other allergens and proteins reported in the Protein Data Bank.

METHODS

X-ray crystallography was used to determine the structure of Alt a 1 by using a custom-designed set of crystallization conditions. An initial Alt a 1 model was determined by the application of a Ta(6)Br(12)(2+) cluster and single-wavelength anomalous diffraction. Bioinformatic analyses were used to compare the Alt a 1 sequence and structure with that of other proteins.

RESULTS

Alt a 1 is a unique β-barrel comprising 11 β-strands and forms a "butterfly-like" dimer linked by a single disulfide bond with a large (1345 Å(2)) dimer interface. Intramolecular disulfide bonds are conserved among Alt a 1 homologs. Currently, the Alt a 1 structure has no equivalent in the Protein Data Bank. Bioinformatics analyses suggest that the structure is found exclusively in fungi. Four previously reported putative IgE-binding peptides have been located on the Alt a 1 structure.

CONCLUSIONS

Alt a 1 has a unique, dimeric β-barrel structure that appears to define a new protein family with unknown function found exclusively in fungi. The location of IgE antibody-binding epitopes is in agreement with the structural analysis of Alt a 1. The Alt a 1 structure will allow mechanistic structure/function studies and immunologic studies directed toward new forms of immunotherapy for Alternaria species-sensitive allergic patients.

The role of immunotherapy in the management of childhood asthma

Subcutaneous immunotherapy (SCIT) is still questioned as a safe and efficacious way of treating allergic asthma in children. In a Cochrane review published in 2010 it was, however, concluded that SCIT has significant and beneficial effects on symptoms and medication use in both children and adults with mostly mild asthma. Only a few studies have been performed to specifically study if SCIT in children with moderate asthma reduces the need for inhaled corticosteroids. There are conflicting results that illustrate the problem of the heterogeneity of the asthma disease and the fact that allergies may play different roles on the severity and symptoms of the disease. Furthermore, children with severe allergic asthma are often sensitized to multiple allergens, which makes SCIT both complicated and less safe to administer. On the other hand, if the child suffers from asthmatic symptoms despite adherence to pharmacotherapy, omalizumab or a combination of omalizumab and allergen immunotherapy might be useful. There is a need for more studies on this combination before it can be considered as an additional therapy in children with asthma and severe allergies. Sublingual immunotherapy (SLIT) has also been shown to improve asthma symptoms and medication use. SLIT is safe although its efficacy compared with SCIT has been studied very little. Another approach is to try to prevent asthma by treating children with SCIT for allergic rhinoconjunctivitis before asthma has developed. The most attractive prospect, however, is to find ways of preventing asthma by vaccination against the most common viruses, particularly rhinovirus. There is evidence that there are children at high risk of developing asthma in whom a viral infection can also enhance the risk of allergen sensitization. So far this vaccination has not been achievable although research is in progress.