Molecular allergen sensitization of Aspergillus fumigatus between allergic bronchopulmonary aspergillosis and A fumigatus-sensitized asthma in Guangzhou, Southern China

Pseudomonas aeruginosa exotoxin A as a novel allergen induced Non-TH2 inflammation in a murine model of steroid-insensitive asthma

Background

Despite the immediate in vivo occurrence of anaphylactic and allergic reactions following treatment with Pseudomonas aeruginosa exotoxin A (PEA)-based immunotoxins, the immunological role of PEA in asthma pathogenesis remains unclear.

Objective

This study investigated the allergenic potential of PEA and the specific type of asthma induced.

Methods

Recombinant PEA (rPEA) lacking domain Ia (to eliminate non-specific cytotoxicity) was expressed, purified, and employed to detect serum PEA-specific IgE levels in asthmatic patients. Competitive ELISA assays were used to assess rPEA's IgE binding capacity and allergenicity. Additionally, rPEA-challenged C57BL/6 mice were subjected to inflammatory endotyping and therapeutic assays to characterize the allergic nature of PEA.

Results

PEA-specific IgE was identified in 17 (14.2 %) of 120 asthma patients. The rPEA-sensitized and challenged mice had increased PEA-specific immunoglobulins (such as IgE, IgG1 and IgG2a) and developed asthma-like phenotypes with airway hyperresponsiveness, severe airway inflammation, and airway remodeling. Lungs from these mice displayed significant increases in neutrophils and IL-17A+ cells. Innate lymphoid cells (ILCs) produced type 2 cytokines (IL-4, IL-5, and IL-13), whereas Th cells did not. Nonetheless, airway inflammation, rather than hyperresponsiveness, was elicited in non-sensitized mice upon challenge with rPEA. Importantly, rPEA-induced asthmatic mice were unresponsive to dexamethasone treatment.

Conclusion

PEA is a novel allergen that sensitizes asthmatic patients. Furthermore, mice developed steroid-resistant asthma, characterized by an atypical cytokine profile associated with non-TH2 inflammation, only after being sensitized and challenged with rPEA. These findings suggest a potentially significant role for PEA in asthma development, warranting consideration in clinical diagnosis and treatment strategies.

Distribution of Aspergillus species and risk factors for aspergillosis in mainland China: a systematic review

Background

Aspergillus, a widespread fungus in the natural environment, poses a significant threat to human health by entering the human body via the airways and causing a disease called aspergillosis. This study comprehensively analyzed data on aspergillosis in published articles from mainland China to investigate the prevalence of Aspergillus, and risk factors, mortality rate, and underlying condition associated with aspergillosis.

Methods

Published articles were retrieved from Google Scholar, PubMed, and Science Direct online search engines. In the 101 analyzed studies, 3558 Aspergillus isolates were meticulously collected and classified. GraphPad Prism 8 was used to statistically examine the epidemiology and clinical characteristics of aspergillosis.

Results

Aspergillus fumigatus was prominently reported (n = 2679, 75.14%), followed by A. flavus (n = 437, 12.25%), A. niger (n = 219, 6.14%), and A. terreus (n = 119, 3.33%). Of a total of 9810 patients, 7513 probable cases accounted for the highest number, followed by confirmed cases (n = 1956) and possible cases (n = 341). In patients, cough emerged as the most common complaint (n = 1819, 18.54%), followed by asthma (n = 1029, 10.48%) and fever (1024, 10.44%). Of total studies, invasive pulmonary aspergillosis (IPA) was reported in 47 (45.53%) studies, exhibiting an increased prevalence in Beijing (n = 12, 25.53%), Guangdong (n = 7, 14.89%), and Shanghai (n = 6, 12.76%). Chronic pulmonary aspergillosis (CPA) was reported in 14 (13.86%) studies. Among the total of 14 studies, the occurrence of CPA was 5 (35.71%) in Beijing and 3 (21.42%) in Shanghai. Allergic bronchopulmonary aspergillosis (ABPA), was reported at a lower frequency (n = 8, 7.92%), Guangdong recorded a relatively high number (n = 3, 37.5%), followed by Beijing (n = 2, 25.0%), and Shanghai (n = 1, 12.5%). Percentage of death reported: IPA had the highest rate (n = 447, 68.87%), followed by CPA (n = 181, 27.88%) and ABPA (n = 14, 2.15%). Among the aspergillosis patients, 6220 had underlying conditions, including chronic lung disease (n = 3765, 60.53%), previous tuberculosis (n = 416, 6.68%), and organ transplant or organ failure (n = 648, 10.41%). Aspergillosis was also found in patients using corticosteroid therapy (n = 622, 10.0%).

Conclusion

This review sheds light on the prevalence patterns of Aspergillus species, risk factors of aspergillosis, and gaps in surveillance that could be helpful for the control and treatment of aspergillosis and guide the researchers in future studies.

Registration

This systematic review was prospectively registered on PROSPERO: Registration ID CRD42023476870.

Effect of yeast probiotic Saccharomyces boulardii cell wall extract on Aspergillus fumigatus allergenicity in A549 cells

Background and Purpose

Interest in probiotic use for respiratory allergies has increased. In this regard, the present study aimed to evaluate the effect of cell wall extract of Saccharomyces boulardii on Aspergillus fumigatus as an allergenic fungus and its effectiveness in reducing inflammatory cytokines in A549 cells sensitized with A. fumigatus conidia.

Materials and Methods

Cell wall of S. boulardii was prepared and challenged by A. fumigatus conidia at various concentrations. Secretory protease activity was tested using the Casein method. The A. fumigatus allergen 1 (Asp f1) gene expression was calculated by quantitative real-time polymerase chain reaction (qRT-PCR). In another experiment, qRT-PCR was used to examine gene expression of interleukin 13 and interleukin 17 by A549 lung epithelial cells exposed to A. fumigatus conidia and treated with different concentrations of S. boulardii cell wall extract.

Results

Saccharomyces boulardii cell wall extract significantly reduced the protease activity of A. fumigatus at concentrations of 10 and 20 mg/ml (P<0.05). The Asp f1 gene expression was significantly down-regulated in each concentration of S. boulardii cell wall extract (P<0.05). Aspergillus fumigatus conidia upregulated the expression of IL-13 and IL-17 in A549 cells, and S. boulardii cell wall extract could downregulate the expression of the mentioned cytokines at concentrations of 10 and 20 mg/ml (P<0.05).

Conclusion

According to the results, it can be concluded that S. boulardii cell wall extract could be a candidate for IL-13- and IL-17-induced Aspergillus-mediated allergy and asthma therapies. Nevertheless, future studies need to be conducted on the safety of S. boulardii cell wall extract in vivo and its effects on other arms of allergic hypersensitivity.

A study of allergen detection panel in Guangzhou, southern China based on real-world data from the past 7 years

This study aims to reduce the cost of allergen testing for Guangzhou, China by limiting the number of allergens for which patients are tested, and provide a testing panel to improve diagnostic and therapeutic efficiency. This retrospective study of real-world data from 2012 to 2019 included 39,570 patients with suspected allergies in Guangzhou, southern China. All the patients were tested for one or more of the following allergens serum specific immunoglobulin E (sIgE): Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat dander, dog dander, Artemisia vulgaris, Aspergillus fumigatus, Alternaria alternata, Blattella germanica, egg whites, milk, wheat, peanuts, soybeans, Cancer pagurus, and Penaeus monodon by PhadiaCAP 1000. Totally, only the positive rates of allergens sIgE in D. farinae, D. pteronyssinus, milk, egg whites, B. germanica, C. pagurus, A. alternata, and P. monodon were > 10%, the other allergens were between 4-7%. Moreover, among the allergic diseases, dust mites exhibited the overall highest positive rate, followed by milk and B. germanica. In children, milk was the main allergen, whereas in adults, mites, cockroaches, shrimp, and crab allergens had higher positive rates. The optimal scale analysis shows that the multiple sensitization classification of patients can be divided into three categories: I D. farinae and D. pteronyssinus; II. C. pagurus, P. monodon, and B. germanica; III. Milk and egg whites. Generally, a panel including 4 allergens can detect > 90% of the potential allergy in this local population. In Guangzhou, southern China, D. farinae, milk, B. germanica, and A. alternata as a panel screening allergy for suspected allergic patients was suggested base on this study.

Indoor Bacterial and Fungal Burden in "Moldy" versus "Non-Moldy" Homes: A Case Study Employing Advanced Sequencing Techniques in a US Metropolitan Area

The presence of fungi in the indoor environment is associated with allergies and other respiratory symptoms. The aim of this study was to use sequencing and molecular methods, including next-generation sequencing (NGS) approaches, to explore the bacterial and fungal communities and their abundance in the indoor environment of houses (n = 20) with visible "moldy" (HVM) and nonvisible "non-moldy" (HNM) in Memphis, TN, USA. Dust samples were collected from air vents and ground surfaces, and the total DNA was analyzed for bacteria and fungi by amplifying 16S rRNA and ITS genes on the Illumina Miseq. Results indicated that Leptosphaerulina was the most abundant fungal genus present in the air vent and ground samples from HNM and HVM. At the same time, the most abundant bacterial genera in the air vent and ground samples were Propionibacterium and Streptococcus. The fungi community diversity was significantly different in the air vent samples. The abundance of fungal species known to be associated with respiratory diseases in indoor dust samples was similar, regardless of the visibility of fungi in the houses. The existence of fungi associated with respiratory symptoms was compared with several parameters like dust particulate matter (PM), CO2 level, temperature, and humidity. Most of these parameters are either positively or negatively correlated with the existence of fungi associated with respiratory diseases; however, none of these correlations were significant at p = 0.05. Our results indicate that implementing molecular methods for detecting indoor fungi may strengthen common exposure and risk assessment practices.

Aspergillus Conidia and Allergens in Outdoor Environment: A Health Hazard?

Aspergillus is a genus of saprophytic fungus widely distributed in the environment and associated with soil, decaying vegetation, or seeds. However, some species, such as A. fumigatus, are considered opportunistic pathogens in humans. Their conidia (asexual spores) and mycelia are associated with clinical diseases known as invasive aspergillosis (IA), mainly related to the respiratory tract, such as allergic asthma, allergic bronchopulmonary aspergillosis (ABPA), or hypersensitivity. However, they can also disseminate to other organs, particularly the central nervous system. Due to the dispersal mechanism of the conidia through the air, airborne fungal particle measurement should be used to prevent and control this mold. This study aims to measure the outdoor airborne concentration of Aspergillus conidia and the Asp f 1 allergen concentration in Bellaterra (Barcelona, Spain) during 2021 and 2022, and to compare their dynamics to improve the understanding of the biology of this genus and contribute to a better diagnosis, prevention, and therapeutic measures in the face of possible health problems. The results show that both particles were airborne nearly all year round, but their concentrations showed no correlation. Due to Asp f 1 not being present in the conidia itself but being detectable during their germination and in hyphal fragments, we report the relevance of the aero-immunological analysis as a methodology to detect the potential pathogenic hazard of this fungus.

Clinical and immunological characteristics of Aspergillus fumigatus-sensitized asthma and allergic bronchopulmonary aspergillosis

Background

Aspergillus fumigatus (A.f) is a common airborne allergen that contributes to allergic asthma. In some patients, A.f can colonize in the airway and lead to allergic bronchopulmonary aspergillosis (ABPA). However, our understanding of the pathogenesis of A.f-sensitized asthma and ABPA remains inadequate.

Objective

We aimed to investigate the clinical and immunological characteristics of A.f-sensitized asthma and ABPA.

Methods

A total of 64 ABPA and 57 A.f-sensitized asthma patients were enrolled in the study, and 33 non-A.f-sensitized asthma patients served as the control group. The clinical and immunological parameters included lung function, fractional exhaled nitric oxide (FeNO), induced sputum and blood cell analysis, specific IgE/IgG/IgA of A.f and its components, cytokines (IL-33, IL-25, and TSLP) and CD4⁺T cell subsets.

Results

The eosinophils in blood, induced sputum, and FeNO were significantly higher in ABPA patients compared to that in A.f-sensitized patients. The combination of FeNO and eosinophils (EO) parameters presented good diagnostic efficiency in differentiating A.f (+) asthma from ABPA, with a sensitivity of 80% and a specificity of 100%. Specific IgE, IgG, and IgA against A.f also increased in ABPA patients. However, serum IL-25, IL-33, and TSLP showed no significant differences between the two groups. Cell analysis showed an increase in IFN-γ⁺Th1 cells in the ABPA patients. FlowSOM analysis further confirmed that the frequency of CD3⁺CD4⁺PD-1⁺CD127⁺IFN-γ⁺T cells was higher in ABPA patients.

Conclusion

Our findings suggest the distinct humoral and cell immunological responses in A.f-sensitized asthma and ABPA patients. ABPA patients have more severe eosinophilic inflammation and enhanced Th1 responses compared with A.f-sensitized asthma patients.

The Molecular Allergen Recognition Profile in China as Basis for Allergen-Specific Immunotherapy

Approximately 30% of the world population suffers from immunoglobulin-E (IgE)-mediated allergy. IgE-mediated allergy affects the respiratory tract, the skin and the gastrointestinal tract and may lead to life-threatening acute systemic manifestations such as anaphylactic shock. The symptoms of allergy are mediated by IgE-recognition of causative allergen molecules from different allergen sources. Today, molecular allergy diagnosis allows determining the disease-causing allergens to develop allergen-specific concepts for prevention and treatment of allergy. Allergen-specific preventive and therapeutic strategies include allergen avoidance, vaccination, and tolerance induction. The implementation of these preventive and therapeutic strategies requires a detailed knowledge of the relevant allergen molecules affecting a given population. China is the world´s most populous country with around 1.4 billion inhabitants and an estimated number of more than 400 million allergic patients. Research in allergy in China has dramatically increased in the last decade. We summarize in this review article what is known about the dominating allergen sources and allergen molecules in China and what further investigations could be performed to draw a molecular map of IgE sensitization for China as a basis for the implementation of systematic and rational allergen-specific preventive and therapeutic strategies to combat allergic diseases in this country.

Obstructive lung diseases and allergic bronchopulmonary aspergillosis

PURPOSE OF REVIEW

Allergic bronchopulmonary aspergillosis (ABPA) is a disease frequently complicating asthma and cystic fibrosis. ABPA is increasingly recognized in other obstructive lung diseases (OLDs), including chronic obstructive pulmonary disease (COPD) and noncystic fibrosis bronchiectasis. Herein, we summarize the recent developments in ABPA complicating OLDs.

RECENT FINDINGS

Recent research has described the clinical features and natural history of ABPA complicating asthma in children and the elderly. We have gained insights into the pathophysiology of ABPA, especially the role of eosinophil extracellular trap cell death and mucus plugs. The utility of recombinant fungal antigens in the diagnosis of ABPA has been established. Newer, more sensitive criteria for the diagnosis of ABPA have been proposed. Although ABPA is uncommon in COPD and noncystic fibrosis bronchiectasis, aspergillus sensitization is more common and is associated with a higher exacerbation rate.

SUMMARY

Several advances have occurred in the diagnosis and treatment of ABPA in recent years. However, there is an unmet need for research into the genetic predisposition, pathophysiology, and treatment of ABPA. Apart from asthma and cystic fibrosis, patients with other OLDs also require evaluation for Aspergillus sensitization and ABPA.

Molecular allergen sensitization of Aspergillus fumigatus between allergic bronchopulmonary aspergillosis and A fumigatus-sensitized asthma in Guangzhou, Southern China

Background

Few studies have assessed the sensitization of mycotic allergens and Aspergillus fumigatus molecular allergens. This study aimed to investigate the relationships of A fumigatus components and mycotic allergens in allergic bronchopulmonary aspergillosis (ABPA) patients and A fumigatus (Af)‐sensitized asthma patients.

Methods

Serum sIgE levels of Penicillium chrysogenum, Cladosporium herbarum, Mucor racemosus, Candida albicans, Alternaria alternata, Helminthosporium halodes, and A fumigatus allergen components (Asp f 1, Asp f 2, Asp f 3, Asp f 4, and Asp f 6) were measured via the ImmunoCAP assay in 18 ABPA and 54 Af‐sensitized asthma patients in Guangzhou city, China.

Results

94.44% of ABPA patients and 87.04% of Af‐sensitized asthma patients were co‐sensitized to at least one other fungal allergen. The positive rates of Asp f 1 (88.89% vs 59.26%, P < .05), Asp f 2 (66.67% vs 33.33%, P < .05), Asp f 4 (61.11% vs 33.33%, P < .05), and Asp f 6 (66.67% vs 14.81%, P < .001) in ABPA patients were higher than those in Af‐sensitized asthma patients. IgE levels of Asp f 1 (P < .05), Asp f 4 (P < .05), and Asp f 6 (P < .001) were higher in ABPA patients than in Af‐sensitized asthma patients. Optimal scale analysis showed that ABPA was more relevant to Af components (Cronbach's alpha = 90.7%).

Conclusion

The A fumigatus components and their relationships with various mycotic allergens were different in ABPA and Af‐sensitized asthma patients. This finding may help local doctors in the diagnosis and immunotherapy of fungal allergies.