CARD9S12N facilitates the production of IL-5 by alveolar macrophages for the induction of type 2 immune responses.

The adaptor CARD9 functions downstream of C-type lectin receptors (CLRs) for the sensing of microbial infection, which leads to responses by the TH1 and TH17 subsets of helper T cells. The single-nucleotide polymorphism rs4077515 at CARD9 in the human genome, which results in the substitution S12N (CARD9S12N), is associated with several autoimmune diseases. However, the function of CARD9S12N has remained unknown. Here we generated CARD9S12N knock-in mice and found that CARD9S12N facilitated the induction of type 2 immune responses after engagement of CLRs. Mechanistically, CARD9S12N mediated CLR-induced activation of the non-canonical transcription factor NF-κB subunit RelB, which initiated production of the cytokine IL-5 in alveolar macrophages for the recruitment of eosinophils to drive TH2 cell-mediated allergic responses. We identified the homozygous CARD9 mutation encoding S12N in patients with allergic bronchopulmonary aspergillosis and revealed activation of RelB and production of IL-5 in peripheral blood mononuclear cells from these patients. Our study provides genetic and functional evidence demonstrating that CARD9S12N can turn alveolar macrophages into IL-5-producing cells and facilitates TH2 cell-mediated pathologic responses.

Th2-skewed peripheral T-helper cells drive B-cells in allergic bronchopulmonary aspergillosis.

INTRODUCTION: Patients with allergic bronchopulmonary aspergillosis (ABPA) suffer from repeated exacerbations. The involvement of T-cell subsets remains unclear. METHODS: We enrolled ABPA patients, asthma patients and healthy controls. T-helper type 1 (Th1), 2 (Th2) and 17 (Th17) cells, regulatory T-cells (Treg) and interleukin (IL)-21+CD4+T-cells in total or sorted subsets of peripheral blood mononuclear cells and ABPA bronchoalveolar lavage fluid (BALF) were analysed using flow cytometry. RNA sequencing of subsets of CD4+T-cells was done in exacerbated ABPA patients and healthy controls. Antibodies of T-/B-cell co-cultures in vitro were measured. RESULTS: ABPA patients had increased Th2 cells, similar numbers of Treg cells and decreased circulating Th1 and Th17 cells. IL-5+IL-13+IL-21+CD4+T-cells were rarely detected in healthy controls, but significantly elevated in the blood of ABPA patients, especially the exacerbated ones. We found that IL-5+IL-13+IL-21+CD4+T-cells were mainly peripheral T-helper (Tph) cells (PD-1+CXCR5-), which also presented in the BALF of ABPA patients. The proportions of circulating Tph cells were similar among ABPA patients, asthma patients and healthy controls, while IL-5+IL-13+IL-21+ Tph cells significantly increased in ABPA patients. Transcriptome data showed that Tph cells of ABPA patients were Th2-skewed and exhibited signatures of follicular T-helper cells. When co-cultured in vitro, Tph cells of ABPA patients induced the differentiation of autologous B-cells into plasmablasts and significantly enhanced the production of IgE. CONCLUSION: We identified a distinctly elevated population of circulating Th2-skewed Tph cells that induced the production of IgE in ABPA patients. It may be a biomarker and therapeutic target for ABPA.

Th2 cells promote eosinophil-independent pathology in a murine model of allergic bronchopulmonary aspergillosis.

Repeated inhalation of airborne conidia derived from the fungus Aspergillus fumigatus (Af) can lead to a severe eosinophil-dominated inflammatory condition of the lung termed allergic bronchopulmonary aspergillosis (ABPA). ABPA affects about 5 million individuals worldwide and the mechanisms regulating lung pathology in ABPA are poorly understood. Here, we used a mouse model of ABPA to investigate the role of eosinophils and T cell-derived IL-4/IL-13 for induction of allergic lung inflammation. Selective deletion of IL-4/IL-13 in T cells blunted the Af-induced lung eosinophilia and further resulted in lower expression of STAT6-regulated chemokines and effector proteins such as Arginase 1, Relm-α, Relm-ß, and Muc5a/c. Eosinophil-deficient ΔdblGata mice showed lower IL-4 expression in the lung and the number of Th2 cells in the lung parenchyma was reduced. However, expression of the goblet cell markers Clca1 and Muc5a/c, abundance of mucin-positive cells, as well as weight gain of lungs were comparable between Af-challenged ΔdblGata and WT mice. Based on these results, we conclude that T cell-derived IL-4/IL-13 is essential for Af-induced lung eosinophilia and inflammation while eosinophils may play a more subtle immunomodulatory role and should not simply be regarded as pro-inflammatory effector cells in ABPA.

Optimal Aspergillus fumigatus and Asp f 1 serum IgG cut-offs for the diagnosis of allergic bronchopulmonary aspergillosis.

BACKGROUND: The presence of IgG antibodies (Abs) to Aspergillus fumigatus (Af) is a crucial diagnostic criterion for allergic bronchopulmonary aspergillosis (ABPA). Although precipitation is traditionally used to document IgG Abs, anti-Af serum IgG levels can also be measured by enzyme immunoassay (EIA). However, there are insufficient data on the optimal cut-offs to assess diagnostic performance of the EIA method. This study aimed to determine cut-off levels of IgG binding crude Af extracts or recombinant Asp f 1 (by ImmunoCAP®) and to compare their efficacy for ABPA diagnosis with Af-precipitating Abs. METHODS: The age distribution of levels of IgG to crude extracts of Af (Af-IgG) and recombinant Asp f 1 (Asp f 1-IgG) was established using sera from 694 healthy controls (HC). Receiver operating characteristic analysis for Af-IgG and Asp f 1-IgG levels for the purpose of ABPA diagnosis was performed in 306 Af-sensitized asthma patients (including 49 ABPA), and cut-offs were determined. RESULTS: An age-dependent decline in the levels of Af-IgG was observed in HC. Thus, cut-offs for Af-IgG levels were determined separately by age as 60 mg/L for patients aged <55 years, and 45 mg/L for those aged ≥55 years. For Asp f 1-IgG, 6.6 mg/L was set as the cut-off regardless of age. Although such IgG testing by EIA allowed a sufficiently good diagnostic performance, Af-precipitating Abs had better diagnostic applicability for ABPA. CONCLUSIONS: We determined cut-offs for Af-IgG and Asp f 1-IgG measured by EIA, which can be useful in clinical settings where precipitating Abs are unavailable.

Serological analysis of sensitization in allergic bronchopulmonary aspergillosis: a study on allergen components and interspecies relationships.

Background: Serological testing for immunoglobulin (Ig) E or IgG is useful for diagnosing allergic bronchopulmonary aspergillosis (ABPA), as it detects type I and III allergic reactions to Aspergillus species. However, few reports have investigated the allergen component and cross-reactivity among Aspergillus species. We aimed to measure and analyze the levels of IgGs specific to each Aspergillus species and investigate the prevalence of IgEs specific to each allergen component of A. fumigatus (Af) in ABPA patients.Methods: Serum samples were collected from 12 ABPA patients who visited our hospital between February and December 2017, and 16 with Af-sensitized asthma and 41 with Af-unsensitized asthma were controls. Immuno-CAP was performed to analyze the IgEs and IgGs specific to Af, A. niger, A flavus and A. terreus, and IgEs specific to allergen components Asp f 1, 2, 3, 4 and 6.Results: The ABPA group was significantly more frequently sensitized to Asp f 1 and 2 than the control groups. Af-specific IgEs were significantly positively correlated to the IgEs specific to A. flavus, A. niger and A. terreus. Af-specific IgGs were positively correlated to the IgGs specific to all the other species.Conclusions: Tests using allergen components were useful for ABPA diagnosis. Both IgE and IgG were highly cross-reactive among the Aspergillus species. There were many patients apart from asthmatic patients with ABPA, who displayed high Aspergillus IgG values.

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.

An atypical acute exacerbation of COPD due to Aspergillus fumigatus.

A 64-year-old male with a history of stabile chronic obstructive pulmonary disease (COPD) presented with increasing dyspnea and sputum for the last two months. Complete blood count showed WBC 14x103/ml, Hgb: 14.2 g/dL and eosinophilia. Blood biochemistry was normal. Chest x-ray showed hyperlucency while thorax computed tomography (CT) revealed obstructive lung disease and bronchiectasis. Pulmonary function tests demonstrated severe obstructive lung disease and a negative bronchoreversibility with a moderately reduced diffusing capacity/alveolar volume (DLCO/VA). ABG gases revealed significant hypoxemia. Sputum culture was negative. Total IgE was 1140 ng/ml. Aspergillus RAST, precipitins and aspergillusgalactomannan antigen were positive. CF genetic screening tests gave negative results. Allergic bronchopulmonary aspergillosis  (ABPA) is a hypersensitivity reaction that occurs due to bronchial aspergillus colonization. It is most common in patients with asthma and cystic fibrosis. We present a COPD case with an acute exacerbation due to Aspergillus fumigatus that lead to an aberrant clinical profile unresponsive to conventional treatment. Clinicians should consider Aspergillus fumigatus as an etiologic agent in an atypical and severe COPD exacerbation.

[Allergic bronchopulmonary aspergillosis]. / Aspergillose bronchopulmonaire allergique.

Allergic bronchopulmonary aspergillosis (ABPA) is a specific complex immunological response to the spores of Aspergillus fumigatus (Af) colonizing the bronchi of asthmatic or cystic fibrosis patients. Recurrent episodes of bronchial obstruction and inflammation, as well as mucoid impaction cause bronchiectasis, pulmonary infiltrates and fibrotic alterations of the lung parenchyma, resulting in significant morbidity and mortality. The pathogenesis of ABPA remains incompletely understood, so it is not clear why certain colonized subjects develop hypersensitivity to Af, and why some sensitized patients develop ABPA and others do not. There is no simple and specific test for diagnosing ABPA. The diagnosis is based on the combination of clinical, radiological and immunological criteria. Systemic steroids are the cornerstone of treatment.

L'aspergillose bronchopulmonaire allergique (ABPA) est une réponse immunologique spécifique complexe contre les spores d'Aspergillus fumigatus (Af) qui colonisent les bronches de patients asthmatiques ou mucoviscidosiques. Les épisodes répétés d'obstruction et d'inflammation bronchiques et d'impactions mucoïdes génèrent des bronchiectasies, des infiltrats pulmonaires et des altérations fibrotiques du parenchyme pulmonaire, d'où une morbi-mortalité significative. La pathogenèse de l'ABPA reste mal comprise, si bien qu'on ne sait pas véritablement pourquoi certains sujets colonisés développent une hypersensibilité à Af, et pourquoi certains patients sensibilisés développent une ABPA et d'autres pas. Il n'y a pas de test simple et spécifique qui permette de diagnostiquer une ABPA. Le diagnostic se base sur l'association de critères cliniques, radiologiques et immunologiques. Les stéroïdes systémiques sont la pierre angulaire du traitement.

Role of Aspergillus fumigatus-Specific IgE in the Diagnosis of Allergic Bronchopulmonary Aspergillosis.

INTRODUCTION: Allergic bronchopulmonary aspergillosis (ABPA) has been regarded as a rare disease in China due to the lack of quantitative detection of Aspergillus fumigatus-specific IgE (sIgE). We compared the diagnostic rate of ABPA among asthma patients with or without A. fumigatus-sIgE screening tests to evaluate the benefit of the tests in diagnosing ABPA. METHODS: We reviewed the detection rate of A. fumigatus-sIgE and the diagnostic rate of ABPA in 1842 asthma patients in the First Affiliated Hospital of Zhejiang University from 2014 to 2016. Additionally, we collected 144 asthma cases from November 2016 to March 2017 to detect the total serum IgE, A. fumigatus-sIgE and sIgE against mixed mold extract, the ABPA diagnostic rate of these patients was then compared with the total cohort. Total serum IgE, A. fumigatus-sIgE and sIgE against mixed mold extract were also tested in 30 patients identified with Aspergillus-positive sputum culture to analyze the incidence of ABPA. RESULTS: Among the 1,842 asthma cases, 566 were inspected for total IgE; 308 (55.40%) were total IgE-positive and 58 (10.43%) had total IgE > 1,000 IU/mL. In contrast, only 126 cases were tested for A. fumigatus-sIgE (6.84%), and 28 had A. fumigatus-sIgE > 0.35 kUA/L (22.22%). Eleven patients were finally diagnosed with ABPA. Of 1,842 asthma patients, only 0.6% were diagnosed with ABPA if the A. fumigatus-sIgE was not detected at first. Moreover, among the 144 asthma cases that were selected for total IgE, A. fumigatus-sIgE, and sIgE against mixed mold extract screening tests, 12 had total IgE > 1,000 IU/mL (8.33%), 11 had A. fumigatus-sIgE > 0.35 kUA/L (7.64%), and 14 had sIgE against mixed mold extract > 0.35 (9.72%); 7 of these patients were confirmed as having ABPA according to the ISHAM guidelines (4.86%) but only 2 without A. fumigatus-sIgE screening test were diagnosed with ABPA (1.39%) (p = 0.000). Of the 30 Aspergillus-positive sputum culture cases, 4 had A. fumigatus-sIgE > 0.35 kUA/L (13.33%), but none was diagnosed with ABPA. CONCLUSIONS: Routine A. fumigatus-sIgE screening for asthma patients can significantly improve the diagnostic rate of ABPA.

Prevalence of sensitization to Aspergillus flavus in patients with allergic bronchopulmonary aspergillosis.

Aspergillus fumigatus is the most common Aspergillus species worldwide; however, A. flavus has also been shown to be prevalent in North India. Herein, we investigate the prevalence of sensitization to A. flavus in subjects with allergic bronchopulmonary aspergillosis (ABPA). We also evaluate the occurrence of allergic bronchopulmonary mycosis (ABPM) due to A. flavus. Treatment-naive subjects with ABPA underwent sputum culture; and, skin testing, fungal-specific immunoglobulin E (IgE) and serum precipitation tests for A. fumigatus and A. flavus. Sensitization to A. flavus was diagnosed if any immunological test for A. flavus was positive in subjects with ABPA. ABPM was labelled as probable if sputum cultures grew A. flavus and A. flavus-specific IgE was greater than A. fumigatus-specific IgE; and, possible if only A. flavus-specific IgE was greater than A. fumigatus-specific IgE. Fifty-three subjects with a mean (SD) age of 34.2 (12.8) years were included. Sensitization to A. flavus was seen in 51 (96.2%) subjects, with overlap occurring in 49 (92.5%), 21 (39.6%), and 12 (22.6%) instances on fungal-specific IgE, skin prick test and precipitins, respectively. Sputum culture was positive in 18 (33.9%; A. flavus [n = 12], A. fumigatus [n = 6]) subjects. ABPM due to A. flavus was diagnosed in 16 (30.2%) subjects (10 probable, 6 possible). They were more likely to have high-attenuation mucus and a trend towards higher occurrence of sinusitis, compared to ABPA. We found a high occurrence of sensitization to A. flavus in subjects with ABPA. Subjects with A. flavus-related ABPM had a higher likelihood of high-attenuation mucus and probability of sinusitis. More studies are required to confirm this observation.

Need to re-look cut-off of Aspergillus-specific IgE levels in children with ABPA.

The cut-offs for total and specific IgE used for diagnosing ABPA in children have been adopted from adult literature and have not been validated in the paediatric population. To establish the ideal cut-offs of total IgE and Aspergillus-specific IgE for the diagnosis of ABPA in children. This study was a prospective observational case-control study, conducted in a tertiary care hospital in North India, enrolling 140 children with partly controlled and uncontrolled asthma. Seventy children had ABPA based on the Rosenberg-Patterson Criteria (Cases) whereas 70 children were without ABPA (Controls). All children were subjected to clinical examination and investigations such as absolute eosinophil count, total IgE, Aspergillus-specific IgE, Aspergillus skin prick test and radiological tests. ROC curve analysis was done to determine the ideal cut-offs of total and specific IgE to diagnose ABPA. The ROC curve analysis determined 1204IU/L as the cut-off value of total IgE with a sensitivity of 79.7% (95%CI 68.31% to 88.44%) and specificity of 53.1% (95%CI 40.23 to 65.7). The ROC analysis of specific IgE levels of children with ABPA determined the cut-off value of 0.49 KAU/L with a sensitivity of 94.03% (95%CI 85.41 to 98.35) and specificity of 88.89% (95%CI 75.94% to 96.29%). We propose that the cut-offs of total and specific IgE need to be relooked in the paediatric population. Cut-offs of total IgE as 1204 IU/L and for Aspergillus-specific IgE as 0.49KAU/L seem appropriate. Large multicentric studies should be conducted to determine the ideal values for diagnosing paediatric ABPA.

Allergic bronchopulmonary aspergillosis.

Allergic bronchopulmonary aspergillosis (ABPA) occurs in patients with asthma or cystic fibrosis, and results in pulmonary infiltrates, tenacious mucus plugs that harbor hyphae of Aspergillus fumigatus, elevations of total serum immunoglobulin E concentration and peripheral blood and sputum eosinophilia. Bronchiectasis is an irreversible complication of ABPA. The key to early diagnosis is to consider ABPA in anyone with asthma or cystic fibrosis and with a positive skin test result for Aspergillus, and/or recurrent infiltrates on radiographs. The differential diagnosis for ABPA in patients with asthma includes diseases in which there is an overlap of asthma, peripheral blood eosinophilia, and radiographic infiltrates. Examples include chronic eosinophilic pneumonia, Churg-Strauss syndrome, drug-induced pulmonary infiltrates, infection with a parasite, asthma with atelectasis, and lymphoma. Mucus plugging that causes a "tree in bud" pattern on computerized tomography examination of the lungs may be from ABPA or other conditions, such as nontuberculous (atypical) mycobacteria (Mycobacteria avium-Mycobacteria intracellulare complex). Prednisone is indicated to clear pulmonary infiltrates, and a usual course is for 3 months. Itraconazole and voriconazole are adjunctive, and drug-drug interactions must be considered because azoles decrease elimination of various medications. Although not familial in most patients, presentation of Aspergillus fumigatus f1 (Asp f1) antigen is restricted to specific major histocompatibility complex (MHC) class II molecules, Human Leukocyte Antigen-DR2 (HLA-DR2), and HLA-DR5. There is an increased number of CD4+ T-helper type 2 lymphocytes in bronchoalveolar lavage, and A. fumigatus can serve as a growth factor of eosinophils potentiating the effects of interleukin (IL) 3, IL-5, and Granulocyte-colony stimulating factor (G-CSF). Eosinophils interact directly with A. fumigatus spores and generate extracellular traps, which can injure the bronchial epithelium.

Eosinophils release extracellular DNA traps in response to Aspergillus fumigatus.

BACKGROUND: Eosinophils mediate the immune response in different infectious conditions. The release of extracellular DNA traps (ETs) by leukocytes has been described as an innate immune response mechanism that is relevant in many disorders including fungal diseases. Different stimuli induce the release of human eosinophil ETs (EETs). Aspergillus fumigatus is an opportunistic fungus that may cause eosinophilic allergic bronchopulmonary aspergillosis (ABPA). It has been reported that eosinophils are important to the clearance of A fumigatus in infected mice lungs. However, the immunological mechanisms that underlie the molecular interactions between A fumigatus and eosinophils are poorly understood. OBJECTIVE: Here, we investigated the presence of EETs in the bronchial mucus plugs of patients with ABPA. We also determined whether A fumigatus induced the release of human eosinophil EETs in vitro. METHODS: Mucus samples of patients with ABPA were analyzed by light and confocal fluorescence microscopy. The release of EETs by human blood eosinophils was evaluated using different pharmacological tools and neutralizing antibodies by fluorescence microscopy and a fluorimetric method. RESULTS: We identified abundant nuclear histone-bearing EETs in the bronchial secretions obtained from patients with ABPA. In vitro, we demonstrated that A fumigatus induces the release of EETs through a mechanism independent of reactive oxygen species but associated with eosinophil death, histone citrullination, CD11b, and the Syk tyrosine kinase pathway. EETs lack the killing or fungistatic activities against A fumigatus. CONCLUSIONS: Our findings may contribute to the understanding of how eosinophils recognize and act as immune cells in response to A fumigatus, which may lead to novel insights regarding the treatment of patients with ABPA.

[The diagnostic value of combined specific IgG and specific IgE of Aspergillus fumigatus in allergic broncho pulmonary aspergillosis and severe asthma with fungal sensitization].

This study aims to explore the diagnostic value of specific immunoglobulin E (sIgE) and specific immunoglobulin G (sIgG) of Aspergillus fumigatus in the diagnosis of allergic broncho-pulmonary aspergillosis (ABPA) and severe asthma with fungal sensitization (SAFS). A total of 17 ABPA patients and 14 SAFS patients were enrolled. The levels of sIgG [2 294.00 (1 527.00, 14 170.00) U/ml vs. 972.60 (650.90, 1 792.00) U/ml] and sIgE [8.77 (1.64, 16.85) kU/L vs. 1.04 (0.70, 2.05) kU/L] in ABPA patients were significantly higher than those in SAFS patients (P<0.05). Aspergillus fumigatus sIgG was strongly correlated with Aspergillus fumigatus sIgE (r(s)=0.797, P<0.001) in ABPA patients. When combined with Aspergillus fumigatus sIgG (>1 000.00 U/mL) and Aspergillus fumigatus sIgE (>1.00 kU/L), the sensitivity was 82.3% and specificity 78.6% for the differential diagnosis of ABPA and SAFS. It demonstrates the diagnostic value of Aspergillus fumigatus sIgG and sIgE.

[Pulmonary Aspergillosis in immunocompetent patient]. / Aspergillose pulmonaire chez le patient immunocompétent.

Aspergillus is a group of molds which is found everywhere worldwide, exposition of human being is common. Most of immunocompetent people do not develop disease caused by Aspergillus. However, diseases in different forms may occur in certain conditions in immunocompetent patient. These diseases include hypersensitivity reactions, like allergic broncho-pulmonary aspergillosis, or infectious process like chronic pulmonary aspergillosis or invasive pulmonary aspergillosis. This article reviewed the clinical features of these diseases and the current available diagnostic techniques.

Aspergillus englobe un groupe de champignons ubiquitaires auquels l'être humain est quotidiennement exposé. Il est rarement pathogène chez le patient immunocompétent, cependant il peut être responsable de différentes formes de maladies dans certaines conditions. Ces pathologies comprennent des réactions d'hypersensibilité, comme l'aspergillose bronchopulmonaire allergique, ou des processus infectieux comme l'aspergillose pulmonaire chronique et l'aspergillose pulmonaire invasive aiguë. Cet article aborde les situations cliniques lors desquelles ces pathologies doivent être suspectées, tout en décrivant les caractéristiques de ces dernières et les moyens diagnostiques à disposition.

Airway epithelial phosphoinositide 3-kinase-δ contributes to the modulation of fungi-induced innate immune response.

BACKGROUND: Respiratory fungal exposure is known to be associated with severe allergic lung inflammation. Airway epithelium is an essential controller of allergic inflammation. An innate immune recognition receptor, nucleotide-binding domain, leucine-rich-containing family, pyrin-domain-containing-3 (NLRP3) inflammasome, and phosphoinositide 3 kinase (PI3K)-δ in airway epithelium are involved in various inflammatory processes. OBJECTIVES: We investigated the role of NLRP3 inflammasome in fungi-induced allergic lung inflammation and examined the regulatory mechanism of NLRP3 inflammasome, focusing on PI3K-δ in airway epithelium. METHODS: We used two in vivo models induced by exposure to Aspergillus fumigatus (Af) and Alternaria alternata (Aa), as well as an Af-exposed in vitro system. We also checked NLRP3 expression in lung tissues from patients with allergic bronchopulmonary aspergillosis (ABPA). RESULTS: Assembly/activation of NLRP3 inflammasome was increased in the lung of Af-exposed mice. Elevation of NLRP3 inflammasome assembly/activation was observed in Af-stimulated murine and human epithelial cells. Similarly, pulmonary expression of NLRP3 in patients with ABPA was increased. Importantly, neutralisation of NLRP3 inflammasome derived IL-1ß alleviated pathophysiological features of Af-induced allergic inflammation. Furthermore, PI3K-δ blockade improved Af-induced allergic inflammation through modulation of NLRP3 inflammasome, especially in epithelial cells. This modulatory role of PI3K-δ was mediated through the regulation of mitochondrial reactive oxygen species (mtROS) generation. NLRP3 inflammasome was also implicated in Aa-induced eosinophilic allergic inflammation, which was improved by PI3K-δ blockade. CONCLUSION: These findings demonstrate that fungi-induced assembly/activation of NLRP3 inflammasome in airway epithelium may be modulated by PI3K-δ, which is mediated partly through the regulation of mtROS generation. Inhibition of PI3K-δ may have potential for treating fungi-induced severe allergic lung inflammation.

Utility of recombinant Aspergillus fumigatus antigens in the diagnosis of allergic bronchopulmonary aspergillosis: A systematic review and diagnostic test accuracy meta-analysis.

BACKGROUND: The role of recombinant A. fumigatus (rAsp) antigens in the diagnosis of allergic bronchopulmonary aspergillosis (ABPA) has not been systematically evaluated. Herein, we evaluate the utility of recombinant A. fumigatus (rAsp) antigens in diagnosing ABPA. METHODS: We systematically reviewed the PubMed, EmBase and Scopus databases for studies evaluating rAsp antigens in ABPA. The QUADAS-2 tool and the GRADE approach were used to assess the risk of bias and the quality of evidence, respectively. The diagnostic performance of IgE or skin test against rAsp f1, f2, f3, f4, f6 and their combination was evaluated separately for ABPA complicating asthma or cystic fibrosis (CF), using an HSROC model. The reference standard for diagnosing ABPA was the composite (clinical, radiological, immunological) criteria. RESULTS: Our search yielded 26 studies (n = 1694) and 17 studies (n = 1131) for inclusion in the systematic review and meta-analysis, respectively. In asthmatics, the pooled sensitivity for diagnosing ABPA was best for IgE against a combination of rAsp f1 or f3 (96.7%; 95% confidence interval [CI], 87.6-99.2). The pooled specificity for diagnosing ABPA was highest (99.2%; 95% CI, 88.2-99.9) for IgE against a combination of f4 or f6. In CF patients, the pooled sensitivity of rAsp f1 or f3 was 93.3% (95% CI, 55.2-99.9) while the pooled specificity of rAsp f4 or f6 was 93.9% (95% CI, 68.8-99.9). The quality of evidence was low as per the GRADE approach. CONCLUSIONS: A combination of IgE against rAsp antigens (f1, f2, f3, f4 and f6) is likely to be helpful in the diagnosis of ABPA.

Concordance between Aspergillus-specific precipitating antibody and IgG in allergic bronchopulmonary aspergillosis.

BACKGROUND: Several serological tests for specific precipitin or IgG are available to demonstrate type III hypersensitivity reactions to Aspergillus species and are essential for infectious fungal disease diagnosis. These assays are also important for allergic bronchopulmonary aspergillosis (ABPA) diagnosis; however, their concordance in ABPA was not well studied. METHODS: Fifty-two ABPA patients diagnosed based on ISHAM criteria were enrolled. Precipitins and IgG specific to Aspergillus fumigatus, Aspergillus niger, Aspergillus flavus, or Aspergillus terreus were measured using Ouchterlony double immunodiffusion tests and ImmunoCAP method, respectively. A. fumigatus-specific IgG was also determined using complement-fixation (CF) method. RESULTS: Forty-eight percent of cases were double-positive for A. fumigatus-specific precipitin and IgG (ImmunoCAP), whereas 3 (6%) and 14 (28%) cases were positive for precipitin or IgG alone, respectively. Kappa coefficient between these measurements was 0.32, suggesting poor concordance. Double-positive cases were more likely to present: Aspergillus sp. in sputum culture, lower pulmonary functions, peripheral blood eosinophilia, higher total IgE and A. fumigatus-specific IgG titer than precipitin-negative cases. A. fumigatus-specific IgG (CF) was positive only in 8 (15%) cases. The presence of A. fumigatus-specific precipitin or IgG was associated with antibodies specific for other Aspergillus spp., suggesting cross-reactivity. CONCLUSIONS: Positive rate of A. fumigatus-specific precipitin or IgG (ImmunoCAP) was superior to IgG (CF), but relatively poor concordance was noted between precipitin and IgG (ImmunoCAP). Positive precipitin for A. fumigatus suggests more active diseases. Cross-reactivity may exist between antibodies to different Aspergillus spp. Therefore, the type III hypersensitivity results in ABPA diagnosis should be carefully evaluated.

Allergic bronchopulmonary aspergillosis in Japan: A nationwide survey.

BACKGROUND: Allergic bronchopulmonary aspergillosis (ABPA) is an allergic pulmonary disease characterized by a hypersensitivity reaction to Aspergillus species colonizing the airways. The clinical characteristics of ABPA may differ depending on genetic and environmental background. We performed a nationwide survey to determine the clinical characteristics of ABPA in Japan. METHODS: In 2013, a questionnaire on physician-diagnosed ABPA/allergic bronchopulmonary mycosis was sent to 903 medical centers specializing in respiratory or allergic diseases. Cases fulfilling the following criteria were categorized as possible ABPA-central bronchiectasis (ABPA-CB): 1) presence of specific serum immunoglobulin E (IgE) antibodies or a positive skin reaction to Aspergillus, and 2) bronchiectasis or mucoid impaction in the central bronchi. RESULTS: Of 499 physician-diagnosed cases reported by 132 clinical centers, 358 cases met the criteria for possible ABPA-CB. Median age of ABPA-CB onset was 57 (interquartile range, 44-68) years; later-onset disease, developing ≥50 years of age, accounted for 66% of the cases and was associated with female sex, delayed onset of asthma, and lower levels of serum IgE. A third of the patients (120 patients, 34%) exhibited low levels of serum total IgE (<1000 IU/mL). Aspergillus species were isolated from sputum in 126/213 cases (59%), and Schizophyllum commune was identified in 12 (6%) patients. During the course of the treatment, ABPA recurred in 169 (48%) cases. CONCLUSIONS: This nationwide survey identified several unique clinical characteristics of ABPA in Japan, such as late-onset, relatively lower serum IgE levels, and frequent recurrences/flares.