Allergic bronchopulmonary aspergillosis in asthma: epidemiological, clinical and therapeutic issues

ABPA and AFRS: addressing prevalence, early diagnosis, allergens, and occupational concerns

OBJECTIVE

This study aimed to comprehensively investigate the prevalence of ABPA and AFRS, scrutinize existing diagnostic criteria and immunoassays, pinpoint their limitations, highlight ABPA as an occupational health implication, and identify suggestive measures to improve ABPA diagnosis in the context of Occupational Health Nursing and primary healthcare.

DATA SOURCES

The data sources such as PubMed, Health and Safety Science Abstracts, OSH Update, Medline, and Google Scholar were searched.

STUDY SELECTIONS

All published studies in the English language from 1990 till Oct, 2023 using Mesh terms keywords "Allergic bronchopulmonary aspergillosis," "Allergic fungal rhinosinusitis," "Signs and Symptoms," "Rapid Diagnostic Tests," "Diagnosis," "Occupational Health," "Occupational Health Nursing," "Prevalence," "Allergens" following "Boolean operators" search strategy were selected.

RESULTS

This review succinctly covered signs, symptoms, and prevalence data concerning ABPA and AFRS. It briefly discussed existing diagnostic criteria and immunoassays, highlighted factors influencing the assay's variability, and underscored the role and scope of specific allergens toward improved, simple, and early ABPA diagnosis. ABPA as a neglected occupational health concern was emphasized, and the importance of RDTs in the context of healthcare professionals and OHNs was stated. Finally, this study suggested analyzing the impact of compromised post-pandemic immune status and the use of immunosuppressive drugs on ABPA prevalence among vulnerable communities and occupations.

CONCLUSION

To conclude, global and Indian ABPA and AFRS prevalence data, factors influencing existing assay variability, and the scope of improvement in RDTs for ABPA diagnosis in the background of primary healthcare professionals and OHNs were addressed.

CT Imaging Assessment of Response to Treatment in Allergic Bronchopulmonary Aspergillosis in Adults With Bronchial Asthma

BACKGROUND

One of the major challenges in managing allergic bronchopulmonary aspergillosis remains consistent and reproducible assessment of response to treatment.

RESEARCH QUESTION

What are the most relevant changes in CT scan parameters over time for assessing response to treatment?

STUDY DESIGN AND METHODS

In this ancillary study of a randomized clinical trial (NebuLamB), patients with asthma with available CT scan and without exacerbation during a 4-month allergic bronchopulmonary aspergillosis exacerbation treatment period (corticosteroids and itraconazole) were included. Changed CT scan parameters were assessed by systematic analyses of CT scan findings at initiation and end of treatment. CT scans were assessed by two radiologists anonymized to the clinical data. Radiologic parameters were determined by selecting those showing significant changes over time. Improvement of at least one, without worsening of the others, defined the radiologic response. Agreement between radiologic changes and clinical and immunologic responses was likewise investigated.

RESULTS

Among the 139 originally randomized patients, 132 were included. We identified five CT scan parameters showing significant changes at end of treatment: mucoid impaction extent, mucoid impaction density, centrilobular micronodules, consolidation/ground-glass opacities, and bronchial wall thickening (P < .05). These changes were only weakly associated with one another, except for mucoid impaction extent and density. No agreement was observed between clinical, immunologic, and radiologic responses, assessed as an overall response, or considering each of the parameters (Cohen κ, -0.01 to 0.24).

INTERPRETATION

Changes in extent and density of mucoid impaction, centrilobular micronodules, consolidation/ground-glass opacities, and thickening of the bronchial walls were found to be the most relevant CT scan parameters to assess radiologic response to treatment. A clinical, immunologic, and radiologic multidimensional approach should be adopted to assess outcomes, probably with a composite definition of response to treatment.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02273661; URL: www.

CLINICALTRIALS

gov).

Aspergillus Sensitization and Allergic Bronchopulmonary Aspergillosis in Asthmatic Children: A Systematic Review and Meta-Analysis

Background: The prevalence of aspergillus sensitization (AS) and allergic bronchopulmonary aspergillosis (ABPA) in asthmatic children remains unclear. Objective: To systematically review the literature to estimate the prevalence of AS and ABPA in children with bronchial asthma. Methods: We searched the PubMed and Embase databases for studies reporting the prevalence of AS or ABPA in pediatric asthma. The primary outcome was to assess the prevalence of AS, while the secondary outcome was to evaluate the prevalence of ABPA. We pooled the prevalence estimates using a random effects model. We also calculated the heterogeneity and publication bias. Results: Of the 11,695 records retrieved, 16 studies with 2468 asthmatic children met the inclusion criteria. Most studies were published from tertiary centers. The pooled prevalence of AS in asthma (15 studies; 2361 subjects) was 16.1% (95% confidence intervals [CI], 9.3-24.3). The prevalence of AS was significantly higher in prospective studies, studies from India, and those from developing countries. The pooled prevalence of ABPA in asthma (5 studies; 505 children) was 9.9% (95% CI, 0.81-27.6). There was significant heterogeneity and publication bias for both outcomes. Conclusions: We found a high prevalence of AS and ABPA in asthmatic children. There is a need for community-based studies from different ethnicities using a standard methodology to ascertain the true prevalence of AS and ABPA in pediatric asthma.

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.

Complementary Roles of Short and Long Pentraxins in the Complement-Mediated Immune Response to Aspergillus fumigatus Infections

The ubiquitous mold Aspergillus fumigatus is the major etiologic agent of invasive aspergillosis, a life-threatening infection amongst immune compromised individuals. An increasing body of evidence indicates that effective disposal of A. fumigatus requires the coordinate action of both cellular and humoral components of the innate immune system. Early recognition of the fungal pathogen, in particular, is mediated by a set of diverse soluble pattern recognition molecules (PRMs) that act as "ancestral antibodies" inasmuch as they are endowed with opsonic, pro-phagocytic and killing properties. Pivotal is, in this respect, the contribution of the complement system, which functionally cooperates with cell-borne pattern recognition receptors (PRRs) and other soluble PRMs, including pentraxins. Indeed, complement and pentraxins form an integrated system with crosstalk, synergism, and regulation, which stands as a paradigm of the interplay between PRMs in the mounting and orchestration of antifungal immunity. Following upon our past experience with the long pentraxin PTX3, a well-established immune effector in the host response to A. fumigatus, we recently reported that this fungal pathogen is targeted in vitro and in vivo by the short pentraxin Serum Amyloid P component (SAP) too. Similar to PTX3, SAP promotes phagocytosis and disposal of the fungal pathogen via complement-dependent pathways. However, the two proteins exploit different mechanisms of complement activation and receptor-mediated phagocytosis, which further extends complexity and integration of the complement-pentraxin crosstalk in the immune response to A. fumigatus. Here we revisit this crosstalk in light of the emerging roles of SAP as a novel PRM with antifungal activity.

Nebulised liposomal-amphotericin-B as maintenance therapy in ABPA: a randomised, multicentre, trial

BACKGROUND

In allergic bronchopulmonary aspergillosis (ABPA), prolonged nebulised antifungal treatment may be a strategy for maintaining remission.

METHODS

We performed a randomised, single-blind, clinical trial in 30 centres. Patients with controlled ABPA after a 4-month attack treatment (corticosteroids and itraconazole) were randomly assigned to nebulised liposomal-amphotericin-B or placebo for 6 months. The primary outcome was occurrence of a first severe clinical exacerbation within 24 months following randomisation. Secondary outcomes included the median time-to-first severe clinical exacerbation, number of severe clinical exacerbations per patient, ABPA-related biological parameters.

RESULTS

Among 174 enrolled patients with ABPA from March 2015 through July 2017, 139 were controlled after 4-month attack treatment and were randomised. The primary outcome occurred in 33 (50.8%) of 65 patients in nebulised liposomal-amphotericin-B group and 38 (51.3%) of 74 in placebo group (absolute difference -0.6%, 95% CI -16.8% to +15.6%, odds ratio 0.98, 95% CI 0.50 to 1.90; p=0.95). The median time-to-first severe clinical exacerbation was longer in liposomal-amphotericin-B group, 337 days (IQR, 168 to 476) versus 177 (64 to 288). At the end of maintenance therapy, total immunoglobulin-E and Aspergillus precipitins were significantly decreased in nebulised liposomal-amphotericin-B group.

CONCLUSIONS

In ABPA, maintenance therapy using nebulised liposomal-amphotericin-B did not reduce the risk of severe clinical exacerbation. The presence of some positive secondary outcomes creates clinical equipoise for further research.

Determining the burden of fungal infections in Zimbabwe

Zimbabwe currently faces several healthcare challenges, most notably HIV and associated infections including tuberculosis (TB), malaria and recently outbreaks of cholera, typhoid fever and COVID-19. Fungal infections, which are also a major public health threat, receive considerably less attention. Consequently, there is dearth of data regarding the burden of fungal diseases in the country. We estimated the burden of fungal diseases in Zimbabwe based on published literature and 'at-risk' populations (HIV/AIDS patients, survivors of pulmonary TB, cancer, chronic obstructive pulmonary disease, asthma and patients receiving critical care) using previously described methods. Where there was no data for Zimbabwe, regional, or international data was used. Our study revealed that approximately 14.9% of Zimbabweans suffer from fungal infections annually, with 80% having tinea capitis. The annual incidence of cryptococcal meningitis and Pneumocystis jirovecii pneumonia in HIV/AIDS were estimated at 41/100,000 and 63/100,000, respectively. The estimated prevalence of recurrent vulvovaginal candidiasis (RVVC) was 2,739/100,000. The estimated burden of fungal diseases in Zimbabwe is high in comparison to other African countries, highlighting the urgent need for increased awareness and surveillance to improve diagnosis and management.

Neutrophil and Eosinophil DNA Extracellular Trap Formation: Lessons From Pathogenic Fungi

Fungal infections represent a worldwide health problem. Fungal pathogens are responsible for a variety of conditions, including superficial diseases, allergic pathologies and potentially lethal invasive infections. Neutrophils and eosinophils have been implicated as effector cells in several pathologies. Neutrophils are major effector cells involved in the control of fungal infections and exhibit a plethora of antifungal mechanisms, such as phagocytosis, reactive oxygen species production, degranulation, extracellular vesicle formation, and DNA extracellular trap (ET) release. Eosinophils are polymorphonuclear cells classically implicated as effector cells in the pathogenesis of allergic diseases and helminthic infections, although their roles as immunomodulatory players in both innate and adaptive immunity are currently recognized. Eosinophils are also endowed with antifungal activities and are abundantly found in allergic conditions associated with fungal colonization and sensitization. Neutrophils and eosinophils have been demonstrated to release their nuclear and mitochondrial DNA in response to many pathogens and pro-inflammatory stimuli. ETs have been implicated in the killing and control of many pathogens, as well as in promoting inflammation and tissue damage. The formation of ETs by neutrophils and eosinophils has been described in response to pathogenic fungi. Here, we provide an overview of the mechanisms involved in the release of neutrophil and eosinophil ETs in response to fungal pathogens. General implications for understanding the formation of ETs and the roles of ETs in fungal infections are discussed.

Relationship between spirometry results and colonisation of Aspergillus species in allergic asthma

INTRODUCTION AND OBJECTIVES

Exposure to fungi in patients with asthma leads to the release of various fungal antigens, which can increase the severity of asthma. Regarding this, the present study was conducted to evaluate the relationship between the colonisation of Aspergillus species and spirometry results in allergic asthma.

MATERIALS AND METHODS

Two hundred sixteen patients with mild to severe asthma and 30 healthy controls were included. All participants underwent pulmonary function tests. Furthermore, sputum samples were collected from each subject. Each sputum sample was subjected to direct microscopic examination and fungal culture. All cultured Aspergillus colonies were identified at species level by molecular methods. Finally, all available data from sputum culture and spirometry test were analysed.

RESULTS

Out of 216 sputum samples, 145 (67.1%) were positive for fungal growth. Furthermore, out of 264 grown fungal colonies, 137 (51.9%) were Aspergillus species. Among the Aspergillus isolates, A. flavus (29.2%) was the most prevalent species, followed by A. fumigatus (27.7%). The mean forced expiratory volume in one second (FEV1) in the mild, moderate and severe asthmatic patients with a positive sputum culture for fungi were obtained as 90.0 ± 11.1, 71.1 ± 15.9 and 54.9 ± 16.4, respectively. In general, Aspergillus species colonisation had no statistically significant effect on spirometry results of study patients.

CONCLUSION

Our results showed that there is no difference in the FEV1 and forced vital capacity between Aspergillus positive and negative patients in any asthma severity group.

Deletion of bem46 retards spore germination and may be related to the polar growth of Aspergillus fumigatus

Bud emergence 46 (BEM46), a member of the α/β hydrolase superfamily, has been reported to be essential for polarized growth in Neurospora crassa. However, the role of BEM46 in aspergillus fumigatus (A. fumigatus) remains unclear. In this study, we constructed an A. fumigatus strain expressing BEM46 fused with enhanced green fluorescent protein, and a Δbem46 mutant, to explore the localization and the role of growth of BEM46 in A. fumigatus, respectively. Confocal laser scanning microscopy revealed that BEM46 was dominantly expressed in the sites where hyphae germinated from conidia in A. fumigatus. When compared with the control strain, the Δbem46 mutant exhibited insignificant morphological changes but delayed germination. No significant changes were found regarding the radial growth of both strains in response to various antifungal agents. These results suggest that BEM46 plays an essential role in timely germination in A. fumigatus. From the observation of fluorescence localization, we infer that that BEM46 might be involved in polarized growth in A. fumigatus.

Omalizumab Is an Effective Intervention in Severe Asthma with Fungal Sensitization

BACKGROUND

Severe asthma with fungal sensitization (SAFS) and allergic bronchopulmonary aspergillosis (ABPA) are important complications of severe asthma. The evidence for treating them with omalizumab is limited.

OBJECTIVE

To determine the effectiveness of treatment with omalizumab in patients with severe allergic asthma comparing those with and without evidence of fungal sensitization using data recorded in the Australian Xolair Registry.

METHODS

Data from 205 patients who received omalizumab and recorded in the Australian Xolair Registry were analyzed to determine change in the Juniper 5-item Asthma Control Questionnaire (ACQ-5) score, exacerbation frequency, and oral corticosteroid dose over a 24-month period of omalizumab treatment. Patients were grouped into cohorts on the basis of fungal sensitization, and an analysis of improvement in outcomes between baseline and 24 months was conducted within each group. A further subgroup analysis of patients with ABPA was also conducted.

RESULTS

Patients with SAFS (n = 62), including those with ABPA (ASAFS), were as likely to demonstrate significant improvements in ACQ-5 score and exacerbations and reduced regular oral corticosteroid dose over 24 months as those with severe asthma without sensitization to fungi (n = 156). After adjusting for age, sex, body mass index, smoking history, and baseline FEV₁%, the effects still remained. A subgroup analysis of 11 patients with ABPA similarly demonstrated a significant improvement on omalizumab.

CONCLUSIONS

Omalizumab is an effective therapy in ASAFS, leading to sustained improvements in symptoms and exacerbations for 24 months. The benefit for ABPA is less clear because of the small sample size.

The Rise of Fungi: A Report on the CIFAR Program Fungal Kingdom: Threats & Opportunities Inaugural Meeting

The first meeting of the CIFAR Fungal Kingdom: Threats & Opportunities research program saw the congregation of experts on fungal biology to address the most pressing threats fungi pose to global health, agriculture, and biodiversity. This report covers the research discussed during the meeting and the advancements made toward mitigating the devastating impact of fungi on plants, animals, and humans.

Diagnostic markers of allergic bronchopulmonary aspergillosis in patients with severe asthma

INTRODUCTION

Allergic bronchopulmonary aspergillosis (ABPA) is a lung disease in patients with asthma or cystic fibrosis (CF) caused by chronic allergic inflammation to Aspergillus spp. antigens. The role of different immunological mediators in the formation of chronic allergic inflammation in patients with ABPA is not sufficiently explored.

OBJECTIVES

This study aimed to investigate serum levels of thymic stromal lymphopoietin (TSLP), thymus and activated chemokine (TARC) as well as IL-8 in patients with ABPA, and to evaluate their diagnostic and monitoring value in the disease.

PATIENTS/METHODS

Prospective study included 21 patients with ABPA, 25 patients with severe asthma with fungal sensitisation (SAFS), 37 patients with severe asthma without fungal sensitisation (SAwFS), and 16 healthy people. In patients with ABPA, the serum levels of biomarkers were determined at baseline and after 12 weeks of itraconazole therapy. Serum levels of total IgE, Aspergillus-fumigatus-specific IgE, TSLP, TARC, IL-8 were analysed by enzyme-linked immunosorbent assay.

RESULTS

In patients with ABPA we established significantly higher serum levels of TARC, IL-8, total IgE, Aspergillus-fumigatus-specific IgE and peripheral blood eosinophil counts, compared to patients with SAwFS. There were no differences in TSLP levels between the examined groups of patients. Serum TARC levels were positively correlated to serum total IgE levels, A fumigatus-specific IgE levels and peripheral blood eosinophil counts and also negatively correlated to lung function (FEV₁ ). Longitudinally, serum levels TARC, total IgE and peripheral blood eosinophil counts significant decreased after treatment of ABPA.

CONCLUSION

Thymus and activated chemokine is a useful test in diagnosing and monitoring response to the antifungal treatment of patients with ABPA.

The clinical characteristics and prognosis of ABPA are closely related to the mucus plugs in central bronchiectasis

INTRODUCTION

The characteristics of Allergic Bronchopulmonary Aspergillosis (ABPA) based on its radiological classification is still unclear.

OBJECTIVES

To investigate the clinical significances of ABPA patients with central bronchiectasis (ABPA-CB) by different radiological classifications of mucus plugs.

METHODS

ABPA-CB patients from a pulmonary hospital between 2008 and 2015 were retrospectively included and analysed. According to the chest imaging in their first visit to physician, the ABPA-CB patients were divided into two groups based on the presence of high-attenuation mucus (HAM) or low-attenuation mucus (LAM). The primary endpoint was ABPA relapse within 1 year since the glucocorticoid withdrawal. The relationship between the imaging findings and the clinical prognosis was illuminated.

RESULTS

A total of 125 ABPA patients were analysed in this study. Compared to the LAM group, the HAM group presented higher blood eosinophil cells counts, higher rates of Aspergillus detection isolated in sputum and expectoration of brownish-black mucus plugs, more affected lobes and segments, poorer pulmonary function and higher rate of relapse.

CONCLUSIONS

The clinical characteristics and prognosis of ABPA-CB patients are closely related to its radiological phenotype of mucus plugs in the central bronchiectasis. Clinicians should promote a diversity of personalized treatments for different patients with different radiological characteristics.

Diagnostic Cutoffs and Clinical Utility of Recombinant Aspergillus fumigatus Antigens in the Diagnosis of Allergic Bronchopulmonary Aspergillosis

BACKGROUND

The clinical utility of IgE against recombinant Aspergillus fumigatus (rAsp)-specific antigens in allergic bronchopulmonary aspergillosis (ABPA) remains unclear.

OBJECTIVE

To identify the optimal diagnostic cutoffs of rAsp-specific IgE in differentiating ABPA from A fumigatus-sensitized asthma (ASA), and define their utility in the diagnosis of ABPA.

METHODS

We enrolled consecutive subjects with ASA and ABPA. IgE against rAsp f1, f2, f3, f4, and f6 was assayed in all the subjects. We evaluated 3 fixed cutoffs (0.35, 0.5, and 1.0 kU_A/L) for their diagnostic performance in the entire cohort. We also divided the study population into derivation and validation cohorts. Cutoffs for rAsp-specific IgE were obtained using the receiver-operating characteristic analysis in the derivation cohort. We then evaluated the diagnostic performance of these cutoffs in the validation cohort. We further correlated rAsp-specific IgE levels in ABPA with asthma control, spirometry, imaging, and immunologic markers.

RESULTS

We included 194 subjects (123 ABPA and 71 ASA). The statistically derived cutoffs proved superior to fixed cutoffs. IgE against rAsp f1 yielded the best combination of sensitivity (89%) and specificity (100%). The sensitivity and specificity of IgE against either rAsp f1 (cutoff, 4.465 kU_A/L) or f2 (cutoff, 1.300 kU_A/L) for diagnosing ABPA were 100% and 81%, respectively. The correlation between rAsp-specific IgE and most clinical parameters of ABPA was weak.

CONCLUSIONS

IgE against rAsp f1 and f2 (using receiver-operating characteristic-derived cutoffs) were found to be the most useful in differentiating ABPA from ASA. Because this study was conducted at a single center, our results require further validation.

The role of occupational Aspergillus exposure in the development of diseases

Aspergillus spp. have a high nutritional versatility and good growth on a large variety of construction materials. They also colonize soil or food, but decaying vegetation is their primary ecological niche. Therefore, exposure to fungi may occur at home, during hospitalization, during specific leisure activities, or at the workplace. The development of Aspergillus infections depends on the interplay between host susceptibility and the organism. Environments with high counts of fungal elements (conidia, hyphal fragments and others), high levels of bioarerosols, and elevated concentrations of mycotoxins or other volatile organic compounds should be considered as potential hazards, since they may present a risk to the exposed person. Rural tasks as well as work related to wood and food industries, poultries, swineries, waste handling plants, and other occupational environments involving contaminated organic material are among the ones posing higher respiratory risks to the workers. This paper presents a review of several studies related to occupational and indoor exposure to Aspergillus, potential health effects related to that exposure, and associated exposure assessment procedures.

Lung colonization by Aspergillus fumigatus is controlled by ZNF77

Aspergillus fumigatus is a critical pathogen of humans. Exposure to A. fumigatus conidia occurs frequently but is normally cleared from the respiratory airways. In contrast, individuals with respiratory diseases are often highly colonized by fungi. Here, we use genome-edited epithelial cells to show that the genetic variant rs35699176 in ZNF77 causes loss of integrity of the bronchial epithelium and increases levels of extracellular matrix proteins. These changes promote A. fumigatus conidial adhesion, germination and growth. RNA-seq and LC/MS-MS analysis reveal rs35699176 upregulates vesicle trafficking leading to an increment of adhesion proteins. These changes make cells carrying rs35699176 more receptive to A. fumigatus in the early stages of infection. Moreover, patients with fungal asthma carrying rs35699176^+/- have higher A. fumigatus loads in their respiratory airway. Our results indicate ZNF77 as a key controller of Aspergillus colonization and suggest its utility as a risk-marker for patient stratification.

The pathogenicity ofAspergillus fumigatus, drug resistance, and nanoparticle delivery

The genus Aspergillus includes fungal species that cause major health issues of significant economic importance. These microorganisms are also the culprit for production of carcinogenic aflatoxins in grain storages, contaminating crops, and economically straining the production process. Aspergillus fumigatus is a very important pathogenic species, being responsible for high human morbidity and mortality on a global basis. The prevalence of these infections in immunosuppressed individuals is on the rise, and physicians struggle with the diagnosis of these deadly pathogens. Several virulence determinants facilitate fungal invasion and evasion of the host immune response. Metabolic functions are also important for virulence and drug resistance, since they allow fungi to obtain nutrients for their own survival and growth. Following a positive diagnostic identification, mortality rates remain high due, in part, to emerging resistance to frequently used antifungal drugs. In this review, we discuss the role of the main virulence, drug target, and drug resistance determinants. We conclude with the review of new technologies being developed to treat aspergillosis. In particular, microsphere and nanoparticle delivery systems are discussed in the context of improving drug bioavailability. Aspergillus will likely continue to cause problematic infections in immunocompromised patients, so it is imperative to improve treatment options.

Developments in the diagnosis and treatment of allergic bronchopulmonary aspergillosis

INTRODUCTION

Allergic bronchopulmonary aspergillosis (ABPA) is a complex pulmonary disorder characterized by recurrent episodes of wheezing, fleeting pulmonary opacities and bronchiectasis. It is the most prevalent of the Aspergillus disorders with an estimated five million cases worldwide. Despite six decades of research, the pathogenesis, diagnosis and treatment of this condition remains controversial. The International Society for Human and Animal Mycology has formed a working group to resolve the controversies around this entity. In the year 2013, this group had proposed new criteria for diagnosis and staging, and suggested a treatment protocol for the management of this disorder. Since then, several pieces of new evidence have been published in the investigation and therapeutics of this condition. Areas covered: A non-systematic review of the available literature was performed. We summarize the current evidence in the evaluation and treatment of this enigmatic disorder. We suggest modifications to the existing criteria and propose a new scoring system for the diagnosis of ABPA. Expert commentary: All patients with asthma and cystic fibrosis should routinely be screened for ABPA using A. fumigatus-specific IgE levels. Glucocorticoids should be used as the first-line of therapy in ABPA, and itraconazole reserved in those with recurrent exacerbations and glucocorticoid-dependent disease.

How to invade a susceptible host: cellular aspects of aspergillosis

Diseases caused by Aspergillus spp. and in particular A. fumigatus are manifold and affect individuals suffering from immune dysfunctions, among them immunocompromised ones. The determinants of whether the encounter of a susceptible host with infectious propagules of this filamentous saprobe results in infection have been characterized to a limited extent. Several cellular characteristics of A. fumigatus that have evolved in its natural environment contribute to its virulence, among them general traits as well as particular ones that affect interaction with the mammalian host. Among the latter, conidial constituents, cell wall components, secreted proteins as well as extrolites shape the tight interaction of A. fumigatus with the host milieu and also contribute to evasion from immune surveillance.

A pilot randomized trial of nebulized amphotericin in patients with allergic bronchopulmonary aspergillosis

BACKGROUND AND AIM

Nebulized amphotericin B (NAB) has been used in the management of acute stage and exacerbations of allergic bronchopulmonary aspergillosis (ABPA). Whether NAB can prevent exacerbations of ABPA is not known. Herein, we evaluate the efficacy and safety of NAB in subjects with ABPA complicating asthma.

METHODS

Consecutive subjects of ABPA with recurrent exacerbations were randomized to receive either NAB plus nebulized budesonide (NEB) or NEB alone. The primary outcome was the time-to-first exacerbation of ABPA. The secondary outcomes were the number of subjects with ABPA exacerbations, ACQ7 scores, lung function, IgE levels, and adverse effects of treatment.

RESULTS

Twenty-one subjects (14 men; mean age, 32.3 years) were randomized to either the NAB (n = 12) or the NEB (n = 9) arm. The baseline characteristics were similar in the two groups. The time-to-first exacerbation was similar in the two groups. At one year, the numbers of patients experiencing exacerbation was significantly lower in the NAB arm (1/12 [8.3%] vs. 6/9 [66.7%]; p = 0.016). The other secondary end points were not different between the two groups. There were no major adverse events leading to discontinuation of any of the study drugs. Three patients experienced bronchospasm after first dose of NAB; however, the subsequent doses were well tolerated.

CONCLUSIONS

NAB seems to be beneficial in decreasing the frequency of exacerbations in patients with ABPA complicating asthma. Larger trials are required to confirm our study results.

Combined Allergic Bronchopulmonary Aspergillosis and Eosinophilic Granulomatosis with Polyangiitis: Three Cases and a Review of the Literature

Previous reports of combined allergic bronchopulmonary mycosis (ABPM) and eosinophilic granulomatosis with polyangiitis (EGPA) are limited; however, among 41 cases of ABPM and 18 cases of EGPA treated at our hospital, we experienced three cases of combined ABPM and EGPA. In two of these cases, the diagnosis of EGPA preceded that of ABPM, however, one of the two cases had already shown findings suggestive of ABPM, such as mucous plugs and central bronchiectasis, at the time of the diagnosis of EGPA. In six previously reported cases of combined ABPM and EGPA, ABPM preceded EGPA in four cases. In the other two cases in which EGPA was diagnosed before or simultaneously with ABPM, findings suggestive of ABPM had been detected when EGPA was diagnosed, which suggests that sensitization to fungi resulting in ABPM may play an important role in the development of EGPA. Careful attention should therefore be paid to the possibility that these diseases may coexist during the course of either disease.

Serological diagnosis of allergic bronchopulmonary mycosis: Progress and challenges

Prompt diagnosis of allergic bronchopulmonary mycosis (ABPM) is an important clinical issue in preventing irreversible lung damage. Therefore, a good serological marker for the diagnosis of ABPM is desired in clinical practice. The measurement of IgE antibody to crude Aspergillus fumigatus allergen is considered the first step in screening asthmatic patients for allergic bronchopulmonary aspergillosis (ABPA). However, presence of IgE to A. fumigatus does not always indicate genuine sensitization to A. fumigatus because of cross-reactivity between crude extracts from different fungal sources. The application of molecular-based allergy diagnosis can solve this problem. The specificity of testing can be greatly improved by measuring the IgE antibody to Asp f 1 and f 2, specific allergen components for genuine A. fumigatus allergy. The problem of cross-reactivity between crude fungal extracts is also true for the identification of genuine causal fungi in each ABPM patient. Some patients with ABPM induced by fungi other than Aspergillus may be consistent with ABPA diagnostic criteria because current criteria depend on IgE/IgG reactivity to crude extracts. Accurate identification of genuine causal fungi for ABPM is of clinical importance, considering that clinical presentation, anti-fungal treatment strategies and disease prognosis can be influenced by different causal fungi. The diagnosis of causal fungi can be robustly validated by the confirmation of genuine sensitization to fungi after measuring IgE to specific allergen components, as well as repeated microbiological isolation of the fungi from their airway.

The glycolytic enzyme enolase represents a plasminogen-binding protein on the surface of a wide variety of medically important fungal species

Allergies are an increasing issue in human health and can, eventually, cause severe anaphylactic shock. Aspergillus fumigatus and Candida albicans are leading causes of life-threatening invasive fungal infections in immunocompromised patients, but can also cause severe allergic responses in otherwise healthy individuals. The glycolytic enzyme enolase is known as a major allergen despite its function in intracellular metabolism. Therefore, its presentation on surfaces of different fungal species was investigated by using antibodies raised against recombinant enolases from A. fumigatus and C. albicans. Examination of antibody specificity revealed cross-reactivity to cell-free extracts from Aspergillus terreus, Aspergillus flavus, Aspergillus nidulans and Candida glabrata, but not against any of the three human enolases. Antibody specificity was further confirmed by hybridization with other recombinant fungal enolases, where the antibodies recognized different subsets of fungal enolases. When surface presentation of enolase was tested on intact fungal cells, a positive staining was obtained with those antibodies that also recognized the enzyme from the respective cell-free extract. This implies a general surface presentation of this glycolytic enzyme among fungal species and provides hints for its predominant recognition as an allergen. Additionally, A. fumigatus and C. albicans enolase bound to human plasminogen, which remained accessible for the plasminogen activator uPA. This implies a potential role of enolase in the invasion and dissemination process during fungal infections.

Blood basophil activation is a reliable biomarker of allergic bronchopulmonary aspergillosis in cystic fibrosis

The diagnosis of cystic fibrosis (CF) patients with allergic bronchopulmonary aspergillosis (ABPA) is clinically challenging, due to the absence of an objective biological test. Since blood basophils play a major role in allergic responses, we hypothesised that changes in their surface activation pattern discriminate between CF patients with and without ABPA.

We conducted a prospective longitudinal study (Stanford cohort) comparing basophil activation test CD203c levels by flow cytometry before and after activation withAspergillus fumigatusallergen extract or recombinantAspf1 in 20 CF patients with ABPA (CF-ABPA) and in two comparison groups: CF patients withA. fumigatuscolonisation (AC) but without ABPA (CF-AC; n=13) and CF patients without either AC or ABPA (CF; n=12). Patients were tested every 6 months and when ill with pulmonary exacerbation. We also conducted cross-sectional validation in a separate patient set (Dublin cohort).

Basophil CD203c surface expression reliably discriminated CF-ABPA from CF-AC and CF over time. Ex vivostimulation withA. fumigatusextract or recombinantAspf1 produced similar results within the Stanford (p<0.0001) and the Dublin cohorts. CF-ABPA patients were likelier to have elevated specific IgE toA. fumigatusand were less frequently co-infected withStaphylococcus aureus.

Basophil CD203c upregulation is a suitable diagnostic and stable monitoring biomarker of ABPA in CF.

A randomised trial of glucocorticoids in acute-stage allergic bronchopulmonary aspergillosis complicating asthma

Whether use of high-dose steroids in acute-stage allergic bronchopulmonary aspergillosis (ABPA) is associated with superior outcomes is not known. Herein, we compare the efficacy and safety of two glucocorticoid protocols in ABPA.Treatment-naive ABPA subjects randomly received either high-dose or medium-dose oral prednisolone. The primary outcomes were exacerbation rates and glucocorticoid-dependent ABPA after 1 and 2 years, respectively, of treatment. The secondary end-points were composite response rates after 6 weeks, improvement in lung function, time to first exacerbation, cumulative dose and adverse effects.92 subjects (high-dose n=44, medium-dose n=48) were included in the study. The numbers of subjects with exacerbation after 1 year (high-dose 40.9% versus medium-dose 50%, p=0.59) and glucocorticoid-dependent ABPA after 2 years (high-dose 11.4% versus medium-dose 14.6%, p=0.88) were similar in the two groups. Although composite response rates were significantly higher in the high-dose group, improvement in lung function and time to first exacerbation were similar in the two groups. Cumulative glucocorticoid dose and side-effects were significantly higher in the high-dose group.Medium-dose oral glucocorticoids are as effective and safer than high-dose in treatment of ABPA.

Utility of IgE (total and Aspergillus fumigatus specific) in monitoring for response and exacerbations in allergic bronchopulmonary aspergillosis

The role of total and specific IgE in monitoring treatment responses in allergic bronchopulmonary aspergillosis (ABPA) remains poorly studied. Here in, we evaluate the utility of total and Aspergillus fumigatus specific IgE in the follow-up of ABPA. Eighty-one consecutive treatment-naïve patients of ABPA (acute stage) with pulmonary infiltrates and bronchiectasis underwent measurement of total and A. fumigatus specific IgE at baseline, after 8 weeks of glucocorticoid therapy, and during exacerbations. There was clinical and radiological improvement after treatment with median decline of total IgE by 51.9%. The total IgE declined by at least 35%, 25% and 20% in 69 (85.2%), 76 (93.6%) and 78 (96.3%) patients, respectively. On the other hand, the A. fumigatus specific IgE increased in 42 (51.9%) subjects, and the mean increase was 1.4%, after 8 weeks. Among 13 patients with exacerbation, 12 (92.3%) had a rise of total IgE by >50%. The A. fumigatus specific IgE increased in only five (38.5%) subjects during exacerbation. Thus, the total IgE is a useful test in monitoring treatment responses in ABPA while A. fumigatus specific IgE has limited utility.

Allergic bronchopulmonary aspergillosis in an adult with Kartagener syndrome

Allergic bronchopulmonary aspergillosis (ABPA) is a pulmonary disorder resulting from immune responses directed against inhaled Aspergillus fumigatus antigens. It manifests with poorly controlled asthma, fleeting pulmonary opacities and structural lung damage in the form of bronchiectasis. Initially defined in individuals suffering from bronchial asthma and cystic fibrosis, it has also been described in patients with other structural lung disorders such as chronic obstructive pulmonary disease, pulmonary tuberculosis, idiopathic bronchiectasis and others. Kartagener syndrome is a manifestation of primary ciliary dyskinesia characterised by the presence of dextrocardia, bronchiectasis and chronic sinusitis. We report a case of ABPA in an adult suffering from Kartagener syndrome. We also performed a systematic review of the literature on the association between Kartagener syndrome and ABPA.

Diagnosis of allergic bronchopulmonary aspergillosis: a case-based approach

Allergic bronchopulmonary aspergillosis is a pulmonary disease occurring in patients with asthma or cystic fibrosis, consequent to a dysregulated immune response to inhaled Aspergillus conidia. The usual presentation is with poorly controlled asthma. Patients may also present with expectoration of mucus plugs, hemoptysis, constitutional symptoms and radiological opacities. Patients may experience smoldering lung destruction despite well-controlled asthma. With emerging data, the diagnostic criteria transcribed by an International Expert Committee in 2013 are the latest evidence-based guidelines. Herein, we utilize a case-based approach to elaborate on the diagnosis of this disease. The review intends to provide a lucid understanding of the diagnostic process for the expert as well as the primary physician, involved in management of this enigmatic disorder.

Opportunistic yeast pathogens: reservoirs, virulence mechanisms, and therapeutic strategies

Life-threatening invasive fungal infections are becoming increasingly common, at least in part due to the prevalence of medical interventions resulting in immunosuppression. Opportunistic fungal pathogens of humans exploit hosts that are immunocompromised, whether by immunosuppression or genetic predisposition, with infections originating from either commensal or environmental sources. Fungal pathogens are armed with an arsenal of traits that promote pathogenesis, including the ability to survive host physiological conditions and to switch between different morphological states. Despite the profound impact of fungal pathogens on human health worldwide, diagnostic strategies remain crude and treatment options are limited, with resistance to antifungal drugs on the rise. This review will focus on the global burden of fungal infections, the reservoirs of these pathogens, the traits of opportunistic yeast that lead to pathogenesis, host genetic susceptibilities, and the challenges that must be overcome to combat antifungal drug resistance and improve clinical outcome.

Estimation of the burden of chronic and allergic pulmonary aspergillosis in India

BACKGROUND AND OBJECTIVES

It would be of considerable interest to clinicians if the burden of chronic pulmonary aspergillosis (CPA) and allergic bronchopulmonary aspergillosis (ABPA) in India were known. Herein, we estimate the burden of CPA following pulmonary tuberculosis (PTB), and ABPA (and severe asthma with fungal sensitization [SAFS]) complicating asthma.

METHODS

We used the population estimates for India from the 2011 census data. The burden of asthma was estimated using three different methods (Global Initiative against Asthma [GINA] report statement, World Health Survey [WHS] estimates, Indian study on the epidemiology of asthma and chronic bronchitis [INSEARCH]). Global and India-specific figures were used for calculating the prevalence of ABPA and SAFS. The World Health Organization estimates were used for calculating PTB rates while the frequency of CPA was assessed from a previously published scoping review. Sensitivity analysis was performed to determine the burden in various scenarios.

RESULTS

The total Indian population in 2011 was 1.2 billion. The asthma prevalence in adults was estimated at about 27.6 (range, 17-30) million. The burden of ABPA ranged from 0.12-6.09 million with different assumptions (best estimate, 1.38 [range, 0.86-1.52] million). The prevalence of SAFS was approximated at about 0.52-1.21 million (best estimate, 0.96 [range, 0.6-1.06] million). The incident TB cases were about 2.1 million while the annual incidence of CPA varied 27,000-0.17 million cases, with different estimates. If the mortality of CPA is estimated as 15% annually, the 5-year prevalence of CPA was placed at 290,147 cases with 5-year prevalence rate being 24 per 100,000.

CONCLUSION

There is a significant burden of ABPA, SAFS and CPA in India. Prospective community-based studies are required to accurately determine the prevalence of these disorders.

A report of a successfully treated case of ABPA in an HIV-infected individual

Aspergillus fumigatus is a ubiquitous fungus responsible for a variety of pulmonary diseases, ranging from infection of a pre-existing cavity as in aspergilloma to highly invasive disease in immunocompromised hosts. Allergic bronchopulmonary aspergillosis (ABPA) is a hypersensitivity response mounted against antigens of A. fumigatus manifesting as poorly controlled asthma and bronchiectasis. Although ABPA is not uncommon, occurrence of ABPA in HIV-affected individuals is distinctly rare. We describe the occurrence of ABPA in a 35-year-old woman with poorly controlled asthma since childhood and HIV-1 infection of 11 years duration. This is the second documented case of ABPA in a HIV-affected individual, and the first reported case to be successfully managed with antifungal therapy alone. We also discuss the complex management issues involved in treating ABPA in HIV-affected individuals.

The prevalence of increased serum IgE and Aspergillus sensitization in patients with COPD and their association with symptoms and lung function

Background

Allergy and Aspergillus hypersensitivity (AH) were shown to be associated with severe symptoms or worse lung function in COPD patients. The prevalence of elevated total IgE (T-IgE) and its association with clinical symptoms and lung function in COPD have not been studied. The prevalence of AH and its correlation with clinical characteristics in a COPD cohort of larger sample size is also lacking.

Methods

273 patients with COPD were evaluated by respiratory symptoms, blood test, chest HRCT, lung function, serum detection of T-IgE and Aspergillus specific IgE. Patients with T-IgE ≥ 1000 KU/L were further investigated for allergic bronchopulmonary aspergillosis (ABPA).

Results

The prevalence of elevated T-IgE and AH in patients with COPD was 47.3% and 15.0%, respectively. Eight patients (2.9%) met the diagnostic criteria for ABPA. Compared with the normal T-IgE group, patients with elevated T-IgE had a longer history of dyspnea (p < 0.01), an earlier onset of dyspnea after chronic cough/expectoration (p < 0.01), and were more likely to wheeze (p < 0.01). They also showed worse lung functions and more severe GOLD staging (p < 0.01). Analysis of the clinical data in male patients with smoking as the risk factor showed the same results. To evaluate the clinical characteristics of COPD with AH, patients with elevated T-IgE were further divided into subgroups with and without AH. When compared with the normal T-IgE group, both the two subgroups showed longer history of dyspnea (p < 0.01), an earlier onset of dyspnea (p < 0.01) and a worse status of lung function (p < 0.05). Correlation analysis demonstrated that T-IgE was correlated positively with the time length of dyspnea (r = 0.401, p < 0.001), and the ratio of duration of dyspnea to that of chronic cough/expectoration (r = 0.59, p < 0.001), but negatively with FEV1/FVC% (r = −0.194, p = 0.001), and FEV1%predicted (r = −0.219, p < 0.001).

Conclusions

There was a high prevalence of elevated serum T-IgE and AH in patients with COPD. Serum T-IgE level was correlated with symptoms such as dyspnea and impairment of lung function. Allergens other than Aspergillus may have similar effects on disease expression or progression of COPD.

Cut-off values of serum IgE (total and A. fumigatus -specific) and eosinophil count in differentiating allergic bronchopulmonary aspergillosis from asthma

The cut-off values of immunological tests employed in diagnosis of allergic bronchopulmonary aspergillosis (ABPA) have never been validated. Herein, we compare the immunological findings in patients with ABPA and asthma using receiver operating characteristic analysis. Consecutive asthmatic subjects underwent all the following investigations: Aspergillus skin test, IgE levels (total and A. fumigatus-specific), Aspergillus precipitins, eosinophil count, chest radiograph and CT chest. There were 372 subjects (179 men, mean age 35.9 years) with a mean asthma duration of 8 years. ABPA was diagnosed in 76 patients (64 bronchiectasis, 12 without bronchiectasis). ABPA was separated from asthma using the best cut-off values of total IgE, A. fumigatus IgE and total eosinophil count of 2347 IU ml(-1) , 1.91 kUA l(-1) and 507 cells per μl respectively. The sensitivity/specificity of these parameters were 87/81%; 99/87%; and, 79/76% respectively. The corresponding AUC values were 0.95, 0.90 and 0.82 respectively. The combination of these three tests at the aforementioned cut-offs provided 100% specificity. Our study provides evidence-based cut-off values of IgE (total and A. fumigatus-specific) and eosinophil counts in differentiating ABPA from asthma. As this is a single centre retrospective study, further studies from different centres are required, as these values could vary by ethnicity and environmental exposure.

Burden and distinctive character of allergic bronchopulmonary aspergillosis in India

Allergic bronchopulmonary aspergillosis (ABPA) is an insidious pulmonary disorder caused by hypersensitivity reactions mounted against Aspergillus fumigatus. Usually, complicating the course of patients with asthma and cystic fibrosis, the affliction has recently been described in chronic obstructive pulmonary disease and pulmonary tuberculosis-related fibrocavitary disease. Patients commonly present with poorly controlled asthma, recurrent pulmonary infiltrates and bronchiectasis. More than six decades have elapsed since the first description of this entity; however, the condition remains poorly understood. The International Society for Human and Animal Mycology has formed a working group to address the deficiencies associated with understanding of this disorder. New criteria have been laid down for diagnosis and staging of the disorder, so as to simplify the identification and management of this condition. This review summarizes the recent advances that have taken place in this condition with special emphasis on the burden and distinct character of ABPA in the Indian subcontinent.