Fungal Allergy: Pattern of sensitization over the past 11 years

Fungal allergen sensitization: Prevalence, risk factors, and geographic variation in the United States

BACKGROUND

Many fungal species are associated with the pathogenesis of allergic disease, yet most epidemiologic studies on IgE-mediated fungal sensitization have only included a few species.

OBJECTIVE

We investigated fungal allergen sensitization prevalence, risk factors, and geographic variation in the United States.

METHODS

From 2014 to 2019, a total of 7,912,504 serum-specific IgE (sIgE) test results for 17 fungal species were measured in 1,651,203 patients aged 0-85 years by a US-wide clinical laboratory. Fungal sensitization prevalence, patterns, and relationship with demographic characteristics, clinical diagnoses, and geographic regions were analyzed.

RESULTS

Twenty-two percent of patients were positive (sIgE > 0.10 kUA/L) to at least 1 fungal allergen; 13.7% were positive to >2 fungal allergens. Fungal species-specific positivity rates ranged 7.4-18.6% and were highest for Candida albicans (18.6%), Alternaria alternata (16.6%), Stemphylium herbarum (14.9%), and Aspergillus fumigatus (14.2%). Other fungi that were frequently tested had relatively low positivity rates (eg, Cladosporium herbarum 11.1%, Penicillium chrysogenum 10.7%). Independent risk factors for test positivity for all fungal species included male sex, teen age (highest in those aged 10-19 years), atopic dermatitis, and asthma. Fungal sensitization was generally higher in urban areas and ecoregions composed predominantly of grasslands and prairies compared to woodlands and forest, although there was greater variation in sensitization risk to different fungi in different ecoregions.

CONCLUSION

Independent risk factors for fungal sensitization include male sex, teen ages, atopic dermatitis, asthma, and ecoregion.

Poorly controlled asthma - Easy wins and future prospects for addressing fungal allergy

Poorly controlled asthma is especially common in low resource countries. Aside from lack of access to, or poor technique with, inhaled beta-2 agonists and corticosteroids, the most problematic forms of asthma are frequently associated with both fungal allergy and exposure, especially in adults leading to more asthma exacerbations and worse asthma. The umbrella term 'fungal asthma' describes many disorders linked to fungal exposure and/or allergy to fungi. One fungal asthma endotype, ABPA, is usually marked by a very high IgE and its differential diagnosis is reviewed. Both ABPA and fungal bronchitis in bronchiectasis are marked by thick excess airway mucus production. Dermatophyte skin infection can worsen asthma and eradication of the skin infection improves asthma. Exposure to fungi in the workplace, home and schools, often in damp or water-damaged buildings worsens asthma, and remediation improves symptom control and reduces exacerbations. Antifungal therapy is beneficial for fungal asthma as demonstrated in nine of 13 randomised controlled studies, reducing symptoms, corticosteroid need and exacerbations while improving lung function. Other useful therapies include azithromycin and some biologics approved for the treatment of severe asthma. If all individuals with poorly controlled and severe asthma could be 'relieved' of their fungal allergy and infection through antifungal therapy without systemic corticosteroids, the health benefits would be enormous and relatively inexpensive, improving the long term health of over 20 million adults and many children. Antifungal therapy carries some toxicity, drug interactions and triazole resistance risks, and data are incomplete. Here we summarise what is known and what remains uncertain about this complex topic.

Problems Encountered Using Fungal Extracts as Test Solutions for Fungal Allergy Diagnosis

Fungal allergy is a worldwide public health burden, and problems associated with a reliable allergy diagnosis are far from being solved. Especially, the lack of high-quality standardized fungal extracts contributes to the underdiagnosis of fungal allergy. Compared to the manufacturing processes of extracts from other allergen sources, the processes used to manufacture extracts from fungi show the highest variability. The reasons for the high variability are manifold as the starting material, the growth conditions, the protein extraction methods, and the storage conditions all have an influence on the presence and quantity of individual allergens. Despite the vast variety of studies that have analyzed the impact of the different production steps on the allergenicity of fungal allergen extracts, much remains unknown. This review points to the need for further research in the field of fungal allergology, for standardization and for generally accepted guidelines on the preparation of fungal allergen extracts. In particular, the standardization of fungal extracts has been and will continue to be difficult, but it will be crucial for improving allergy diagnosis and therapy.

Fungal Aeroallergen Sensitization Patterns among Airway-Allergic Patients in Zagazig, Egypt

BACKGROUND

Airway allergies such as asthma and allergic rhinitis, as well as their comorbidities, are increasing worldwide, causing significant socioeconomic health burdens to societies. It is estimated that between 3% and 10% of the population is allergic to fungi. The type of fungal sensitization varies from one geographical region to another. The present study aimed to identify the common fungal aeroallergen sensitization patterns among airway-allergic patients residing in the Zagazig locality, Egypt, in order to obtain a better understanding of fungal allergy, in addition to improving the awareness and management strategies for those patients.

METHODS

The present cross-sectional study included 200 allergic rhinitis and asthma patients. Sensitization to fungal aeroallergens was evaluated by skin prick testing and in vitro measurement of total and specific immunoglobulin E.

RESULTS

As determined by a skin prick test, 58% of the patients studied were allergic to mixed molds. Alternaria alternata was the predominant fungal aeroallergen among the studied patients (72.2%), which was followed by Aspergillus fumigatus (53.45%), Penicillium notatum (52.6%), Candida albicans (34.5%), and Aspergillus niger (25%).

CONCLUSION

Mixed mold sensitization ranked fourth among the most frequent aeroallergens in airway-allergic patients, and Alternaria alternata was the most frequently encountered fungal aeroallergen in the Zagazig locality.

Fungal allergic sensitisation in young rural Zimbabwean children: Gut mycobiome and seroreactivity characteristics

Background

The prevalence of allergic diseases has increased over the last few decades, with sensitisation to fungal allergens and gut microbiome dysbiosis implicated in this trend. The fungal community in the gut (mycobiome) has yet to be characterised and related to fungal allergic sensitisation. Thus, we characterised the gut mycobiome and related it to fungal sensitisation and seroreactivity among Zimbabwean children. We further determined the effect of host age, sex, Schistosoma haematobium infection and mycobiome composition on fungal sensitisation and seroreactivity.

Methods

Using shotgun metagenomic sequencing, we characterised the gut microbiome of stool samples of 116 preschool aged children (PSAC) (≤5 years old, 57(49.1%) male and 59 (50.9%) female). Sensitisation to common fungi in Zimbabwe was assessed using skin prick tests (SPTs). Allergen-specific IgM, IgA, IgG, IgE and IgG4 antibodies were quantified by ELISA. We analysed the relationship between fungal genera and SPT reactivity by ANOVA; fungal genera and IgE antibody reactivity by linear regression; variation in mycobiome abundance with host and environmental factors by PERMANOVA; SPT reactivity and host and environmental factors by logistic regression; seroreactivity and host and environmental factors by ANOVA.

Results

The mycobiome formed <1% of the sequenced gut microbiome and 228 fungal genera were identified. The most abundant genera detected were Protomyces, Taphrina, and Aspergillus. S.haematobium infection had a significant effect on fungal genera. Prevalence of SPT sensitisation to ≥1 fungal species was 96%, and individuals were frequently sensitised to Saccharomyces cerevisiae. Antibodies were detected in 100% of the population. There was no relationship between mycobiome abundance and IgE titres or IgE/IgG4 ratios for each fungal species; no significant differences between SPT reactivity and abundance of fungal species except for S. cerevisiae; and fungal seroreactivity did not significantly differ with age. There were some sex (m>f for, Epicoccum nigrum and Penicillium chrysogenum) and SPT reactivity -related differences in seroreactivity.

Conclusion

This is the first comprehensive characterisation of gut mycobiome and fungal allergic sensitisation of rural children in Zimbabwe. Although reported allergic disease is low there is a high percentage of sensitisation. Further studies with larger populations are required to understand the role of the mycobiome in allergic diseases.

Optimization of approaches to the management of adult patients with severe atopic dermatitis: analysis of real clinical practice outcomes

Atopic dermatitis (AD) is a multifactorial genetically determined immune-mediated skin disease. It is difficult to treat and significantly affects patients quality of life. The development of an integrated approach focusing on atopic multimorbidity, implementation of validated control tools and distinction of clinical parameters specific for different phenotypes of severe forms of disease is especially relevant to patients resistant to standard therapy techniques. Dupilumab, a biologic, is approved for the treatment of the resistant group of patients with moderate to severe AD in the Russian Federation. Dupilumab inhibits the functions of two key cytokines of T2-mediated inflammation IL-4 and IL-13. The article presents personal experience of the authors concerning individual approach to the choice of therapy for the management of this cohort of patients in routine clinical practice. The disease aggravating criteria were determined, which are fundamental for the formation of individual patient portrait for the biologic (dupilumab) treatment for severe AD.

Patterns of allergen sensitization in patients with asthma in Yaqui Valley, Mexico

Introduction. People who live in highly allergenic regions have a greater risk of being sensitized; therefore, these areas have a higher prevalence of mono and polysensitized patients. The aim of the present study was to investigate the allergen sensitization profiles in patients with asthma in an agricultural zone in Mexico.Methods. An analytical cross-sectional study was conducted in a secondary care hospital in Obregon City, Mexico. The allergen sensitization pattern profiles were analyzed through a skin prick test (SPT) in 294 patients. Data was collected before SPT: asthma control was classified according to the Global Initiative for Asthma Criteria, nutritional status was assessed with the Body Mass Index (BMI) using Quetelet's index (BMI = weight/height²), and comorbidities, asthma, and smoking habits were collected from the patients' medical records.Results. In this study, in a group of adults with asthma, the prevalence of sensitization was 77%. The most frequent categories of aeroallergens were in indoors, in zones with weeds and abundant trees. A low proportion of monosensitized patients (2%) was observed. House dust mites were the most common allergens.Conclusions. Our study describes the sensitization pattern among asthma patients. This study will help identify the panel of most common allergens in this region of Mexico, and aid in selection of specific treatment through immunotherapy.

Sensitization against Fungi in Patients with Airway Allergies over 20 Years in Germany

BACKGROUND

Fungal spores are ubiquitous allergens. Severe forms of asthma are particularly highly associated with fungal sensitization. National and international asthma guidelines recommend the implementation of allergen immunotherapy if indicated. Thus, detection and treatment of relevant allergies are key components of primary care of these patients.

OBJECTIVES

The aims of the study were (i) to investigate trends in the prevalence of sensitization to twelve fungi in central Germany over the last 20 years and (ii) to dissect specific sensitization patterns among the 3 most important fungi: Aspergillus, Alternaria, and Cladosporium.

METHODS

This single-center study evaluated skin prick test (SPT) results of 3,358 patients with suspected airway allergies over a period of 20 years (1998-2017).

RESULTS

While 19.2% of all study patients had positive test results to at least 1 of the 3 fungi (Alternaria, Aspergillus, or Cladosporium) in the first study decade, this rate increased to 22.5% in the second decade. Slight increases in sensitization rates to almost all fungi were observed over the 20-year period. In the last decade, polysensitization to Alternaria, Aspergillus, and Cladosporium increased significantly. Sensitization to fungi is age-dependent and peaks in the age-group of 21-40 years during the second decade.

CONCLUSION

Fungi are relevant allergens for perennial and seasonal allergy symptoms. We currently recommend including Aspergillus, Alternaria, and Cladosporium in the standard series of SPTs for airway allergies.

The allergenic activity and clinical impact of individual IgE-antibody binding molecules from indoor allergen sources

A large number of allergens have been discovered but we know little about their potential to induce inflammation (allergenic activity) and symptoms. Nowadays, the clinical importance of allergens is determined by the frequency and intensity of their IgE antibody binding (allergenicity). This is a rather limited parameter considering the development of experimental allergology in the last 20 years and the criteria that support personalized medicine. Now it is known that some allergens, in addition to their IgE antibody binding properties, can induce inflammation through non IgE mediated pathways, which can increase their allergenic activity. There are several ways to evaluate the allergenic activity, among them the provocation tests, the demonstration of non-IgE mediated pathways of inflammation, case control studies of IgE-binding frequencies, and animal models of respiratory allergy. In this review we have explored the current status of basic and clinical research on allergenic activity of indoor allergens and confirm that, for most of them, this important property has not been investigated. However, during recent years important advances have been made in the field, and we conclude that for at least the following, allergenic activity has been demonstrated: Der p 1, Der p 2, Der p 5 and Blo t 5 from HDMs; Per a 10 from P. americana; Asp f 1, Asp f 2, Asp f 3, Asp f 4 and Asp f 6 from A. fumigatus; Mala s 8 and Mala s 13 from M. sympodialis; Alt a 1 from A. alternata; Pen c 13 from P. chrysogenum; Fel d 1 from cats; Can f 1, Can f 2, Can f 3, Can f 4 and Can f 5 from dogs; Mus m 1 from mice and Bos d 2 from cows. Defining the allergenic activity of other indoor IgE antibody binding molecules is necessary for a precision-medicine-oriented management of allergic diseases.

Allergen immunotherapy in asthma: current evidence

Background: Allergic asthma is the predominant phenotype in clinical practice. Allergen immunotherapy is the only curative and specific approach for the treatment of allergies with clinical benefits for several years after its discontinuation. Despite advances, the use of allergen immunotherapy in allergic asthma is still suboptimal and controversial.Objective: The purpose of this article is to review the published data about the impact of allergen immunotherapy with the most commonly used allergen extracts on allergic asthma outcomes, including both clinical parameters and patients' subjective experience (quality of life).Methods: As data sources several databases were used, including PubMed, Scopus, Web of Science (2002-2019) and search in English and Spanish languages was performed using the following terms: "allergen immunotherapy" and "asthma" in combination with "house dust mite", "birch pollen", "grass pollen", "olive tree pollen", "molds", "pets" and "asthma quality of life". Randomised control trials and meta-analysis from reviewed publications were selected.Results: Emerging data relating to the positive impact on asthma outcomes of allergen immunotherapy allows the addition of this treatment as a therapeutic option in mild to moderate asthmatics sensitized to house dust mite and pollens. Limited data are available for patients sensitized to molds and pets, as well in severe allergic asthma population.Conclusion: Allergen immunotherapy remains a potential therapeutic option for some patients with allergic asthma. Further research is needed to define the optimal period of treatment, the possible therapeutic role in the treatment of severe allergic asthma, and the cost-effectiveness of allergen immunotherapy in asthmatic patients.

Feeding Interactions Between Microorganisms and the House Dust Mites Dermatophagoides pteronyssinus and Dermatophagoides farinae (Astigmata: Pyroglyphidae)

The feeding interactions between house dust mites (HDM) and microorganisms are key factors in the survival of mites in human environments. The suitability of different microbes for HDM is not known. Here, microbial species isolated from HDM cultures were offered to HDM in food preference tests under laboratory conditions. The microbial species were added to the rearing diet of mites to reach 7% of Saccharomyces cerevisiae and 10% of each tested microorganism. The suitability of each microbe-supplemented diet for Dermatophagoides pteronyssinus and Dermatophagoides farinae was compared in terms of mite population growth and mite preference in a cafeteria test. The effect of mite feeding on the respiration of microorganisms in the diet was observed in microcosms. HDM were able to feed and reproduce on some bacterial and fungal species, but the suitability of microbial species differed. Increasing the yeast Sa. cerevisiae in the diet from 7 to 17% appeared the most suitable for both mite species. Staphylococcus spp. bacteria were preferred for D. farinae and were suitable for reproduction. The population growth and feeding preferences of D. pteronyssinus and D. farinae with respect to microorganisms indicate that D. farinae can develop on a diet with bacterial (Staphylococcus nepalensis and Staphylococcus kloosii) additions, whereas D. pteronyssinus was successful on a diet with fungal (Aspergillus jensenii and Aspergillus ruber) additions. The bacteria Kocuria rhizophila and Bacillus cereus decreased population growth in D. pteronyssinus, whereas the yeasts Hyphopichia pseudoburtonii, Hyphopichia burtonii, and Candida ciferrii decreased population growth in D. farinae. These results indicate that some microorganisms are an important food source for HDM.

Managing raw materials of vegetable origin increases fungal indoor concentration in food companies

Fungi in indoor environments is a known cause of disease and food spoilage. However, there is currently no legislation or normativity stablishing limits for fungal densities in correlation with these. Moreover, there is little knowledge of the diversity of fungi in indoor environments for industrial areas and in food-related companies in particular, a study has never been performed to evaluate the concentration and diversity of fungi in this type of places. We evaluated the fungal density of 20 food companies. We sampled 100 L of air onto rose bengal-malt extract-agar plates, using an Air Test Omega^® sampler. After incubation, CFUs were counted and identified. Penicillium, Cladosporium and Aspergillus were the most commonly isolated genus, with Penicillium being the only genus to be present in every area sampled. Neither the companies' location nor their room temperature influenced the fungal densities significantly, however, companies using vegetable raw materials had a significantly greater concentration of fungi than the rest of the companies. While all concentrations were within previously suggested levels from a health-related point of view, more information is needed that correlates fungal concentration with food spoilage in order to suggest a range of concentrations focused for food companies' product preservation.

A review on hypersensitivity reactions to fungal aeroallergens in patients with allergic disorders in Iran

Fungal agents account for the clinical manifestation of allergic disorders. The aim of the present study was to review the prevalence of hypersensitivity reactions to fungal aeroallergens in patients with allergic disorders, including allergic rhinitis, asthma, urticaria, and eczema, in Iran. The initial literature search resulted in the identification of 50 records, 26 cases of which met the inclusion criteria. Regarding the methods adopted for the detection of fungal allergens, serum-specific IgE and skin prick tests were used in 6 and 20 studies, respectively. Aspergillus fumigatus and Alternaria alternata sensitization was the most common allergic sensitization among the patients with allergic disorders. According to the reviewed studies, despite the humid climate of the north of Iran, fungal sensitization has a prevalence range of 5-70% in this region. In other regions, such as central and southern Iran, which have a dry and warm climate, fungal sensitization reportedly has a prevalence range of 5-65%. The prevalence of fungal sensitizations varies in different allergic disorders due to the factors related to geographic and genetic issues, gender, sample size, test operator, and assessment method.