Allergic bronchopulmonary aspergillosis: review of literature and proposal of new diagnostic and classification criteria

Azole-resistant aspergillosis

Azole-resistance in Aspergillus fumigatus is emerging and is becoming an increasing problem in the management of aspergillosis. Two types of development of resistance have been described; resistance acquired during azole treatment in an individual patient and through environmental exposure to fungicides. The main molecular mechanism of azole resistance in A. fumigatus is explained by mutations in the cyp51A-gene. The environmental route of resistance development is particularly worrying and may affect all patients whether azole exposed or naïve, and whether suffering from acute or chronic aspergillosis. No management guidelines to assist clinicians confronted with azole-resistant aspergillosis are available and pre-clinical and clinical evidence supporting treatment choices is scarce.

Regulation of B-cell-activating factor expression on the basophil membrane of allergic patients

BACKGROUND

To investigate the modulation of B-cell-activating factor (BAFF) expression on the basophil membrane of allergic patients. BAFF is an important regulator of B-cell activation, proliferation and immunoglobulin production, which may play a role in respiratory allergic diseases in promoting the production of IgE by B cells.

METHODS

Peripheral blood samples of 10 patients with allergic rhinitis, 3 with severe asthma and fungal sensitization (SAFS), 3 with allergic bronchopulmonary aspergillosis (ABPA) and 11 healthy controls were assessed regarding BAFF (CD257) expression using the basophil activation test before and after stimulation with IgE and allergens, as well IgE-independent stimuli, like fMLP, lipotheichoic acid from Staphylococcus aureus (LTA-SA) and lipopolysaccharide (LPS).

RESULTS

BAFF membrane expression did not change after IgE and allergen stimulation both in patients and controls, while it was upregulated by Aspergillus stimulation, both in sensitized patients and controls. In both patients and controls, BAFF expression was significantly upregulated following LTA-SA and β-1,3-glucan exposure (toll-like receptor-2 ligands), but not following LPS stimulation.

CONCLUSIONS

Basophils from allergic and healthy subjects constitutively express membrane BAFF, which is not upregulated by IgE or specific allergens but by TLR-2 ligands (LTA-SA and β-1,3-glucan). Aspergillus fumigatus stimulation was able to upregulate BAFF expression on the basophils of sensitized asthmatic patients, but not via IgE-dependent mechanisms, since results did not differ between the patient and control groups. These findings suggest that basophils may contribute to the polyclonal production of IgE commonly observed in patients with SAFS and ABPA.

British Society for Medical Mycology best practice recommendations for the diagnosis of serious fungal diseases

Invasive fungal diseases are an important cause of morbidity and mortality in a wide range of patients, and early diagnosis and management are a challenge. We therefore did a review of the scientific literature to generate a series of key recommendations for the appropriate use of microbiological, histological, and radiological diagnostic methods for diagnosis of invasive fungal diseases. The recommendations emphasise the role of microscopy in rapid diagnosis and identification of clinically significant isolates to species level, and the need for susceptibility testing of all Aspergillus spp, if treatment is to be given. In this Review, we provide information to improve understanding of the importance of antigen detection for cryptococcal disease and invasive aspergillosis, the use of molecular (PCR) diagnostics for aspergillosis, and the crucial role of antibody detection for chronic and allergic aspergillosis. Furthermore, we consider the importance of histopathology reporting with a panel of special stains, and emphasise the need for urgent (<48 hours) and optimised imaging for patients with suspected invasive fungal infection. All 43 recommendations are auditable and should be used to ensure best diagnostic practice and improved outcomes for patients.

Resistance is not futile: gliotoxin biosynthesis, functionality and utility

Gliotoxin biosynthesis is encoded by the gli gene cluster in Aspergillus fumigatus. The biosynthesis of gliotoxin is influenced by a suite of transcriptionally-active regulatory proteins and a bis-thiomethyltransferase. A self-protection system against gliotoxin is present in A. fumigatus. Several additional metabolites are also produced via the gliotoxin biosynthetic pathway. Moreover, the biosynthesis of unrelated natural products appears to be influenced either by gliotoxin or by the activity of specific reactions within the biosynthetic pathway. The activity of gliotoxin against animal cells and fungi, often mediated by interference with redox homeostasis or protein modification, is revealing new metabolic interactions within eukaryotic systems. Nature has provided a most useful natural product with which to reveal some of its many molecular secrets.

Pulmonary aspergillosis

Aspergillosis is a mycotic disease usually caused by Aspergillus fumigatus, a saprophytic and ubiquitous airborne fungus. Aspergillus-related lung diseases are traditionally classified into four different forms, whose occurrence depends on the immunologic status of the host and the existence of an underlying lung disease. Allergic broncho-pulmonary aspergillosis (ABPA) affects patients with asthma or cystic fibrosis. Saprophytic infection (aspergilloma) occurs in patients with abnormal airways (chronic obstructive pulmonary disease, bronchiectasis, cystic fibrosis) or chronic lung cavities. Chronic necrotizing aspergillosis (semi-invasive form) is described in patients with chronic lung pathology or mild immunodeficiency. Invasive aspergillosis (angio-invasive or broncho-invasive forms) occurs in severely immuno-compromised patients. Knowledge of the various radiological patterns for each form, as well as the corresponding associated immune disorders and/or underlying lung diseases, helps early recognition and accurate diagnosis.

Diagnosis and treatment of pulmonary aspergillosis syndromes

Both inherited and acquired immunodeficiency and chronic pulmonary disease predispose to the development of a variety of pulmonary syndromes in response to Aspergillus, a fungus that is ubiquitous in the environment. These syndromes include invasive aspergillosis, which is now recognized to occur in patients with critical illness without neutropenia and in those with mild degrees of immunosuppression, including from corticosteroid use in the setting of COPD. Chronic pulmonary aspergillosis includes simple aspergilloma, which is occasionally complicated by life-threatening hemoptysis, and progressive destructive cavitary disease requiring antifungal therapy. Allergic bronchopulmonary aspergillosis occurs almost exclusively in patients with asthma or cystic fibrosis. Recent advances in each of these syndromes include a greater understanding of the underlying pathophysiology and hosts at risk; improved diagnostic algorithms; and the availability of more effective and well-tolerated therapies. Improvement in outcomes for Aspergillus pulmonary syndromes requires that physicians recognize the varied and sometimes subtle presentations, be aware of populations at risk of illness, and institute potentially life-saving therapies early in the disease course.

Characterisation of Alternaria alternata manganese-dependent superoxide dismutase, a cross-reactive allergen homologue to Asp f 6

It is well known that Alternaria alternata presents a significant level of allergenic cross-reactivity with several other phylogenetically related and non-related allergenic moulds. To improve the molecular diagnosis, the identification and characterisation of all clinically relevant allergens, including both species-specific and cross-reacting proteins, is required. In this study we report the molecular and immunological characterisation of the A. alternata manganese-dependent superoxide dismutase (Alt a MnSOD) and its cross-reactivity with Asp f 6, a diagnostic marker allergen in allergic bronchopulmonary aspergillosis (ABPA). The cDNA coding for Alt a MnSOD sequence was isolated by RACE and PCR. Alt a MnSOD is a protein of 191 amino acids that presented significant homology and potential cross-reactive epitopes with Asp f 6. The recombinant protein was produced in Escherichia coli and the immunoreactivity was evaluated in patient sera. Immunoblotting analyses showed that seven of sixty-one A. alternata-sensitised patient sera and two ABPA patient sera reacted with the recombinant Alt a MnSOD. The native counterpart contained in both A. alternata and Aspergillus fumigatus extracts inhibited IgE binding to the recombinant molecule. The allergen was named Alt a 14 by the official Allergen nomenclature subcommittee. Thus, Alt a 14 is a relevant allergen in A. alternata sensitisation that may be used to improve diagnostic procedures. Evidence of cross-reactivity between Asp f 6 and Alt a 14-recognition by ABPA patient sera suggest the existence of an Alt a 14-mediated mechanism that, similar to Asp f 6, may be related to the pathogenesis of ABPA.

Chitin enhances serum IgE in Aspergillus fumigatus induced allergy in mice

Aspergillus fumigatus (A. fumigatus) is a ubiquitous fungus that activates, suppresses or modulates the immune response by changing its cell wall structure and by secreting proteases. In this study, we show that chitin acts as an adjuvant in a murine model of A. fumigatus protease induced allergy. The mice were immunised intraperitoneally with A. fumigatus culture filtrate antigen either with or without chitin and were subsequently challenged with the culture filtrate antigen intranasally. Alum was used as an adjuvant control. Compared to alum, chitin induced a weaker inflammatory response in the lungs, measured as the total cell efflux in BAL, EPO and chitinase production. However, chitin enhanced the total IgE, specific IgE and specific IgG1 production as efficiently as alum. Pre-treatment with chitin but not with alum depressed the concentration of the Th2 cytokines IL-4 and IL-13 in BAL fluid. These results shows that chitin, in spite of a reduction of the Th2 cytokine levels in the lungs, enhanced the total and specific IgE production in A. fumigatus culture filtrate induced allergy.

Eosinophilic Pneumonia

Eosinophilic pneumonia may manifest as chronic or transient infiltrates with mild symptoms, chronic idiopathic eosinophilic pneumonia, or the frequently severe acute eosinophilic pneumonia that may be secondary to a variety of causes (drug intake, new onset of tobacco smoking, infection) and that may necessitate mechanical ventilation. When present, blood eosinophilia greater than 1 × 10⁹ eosinophils/L (and preferably greater than 1.5 × 10⁹/L) is of considerable help for suggesting the diagnosis, however it may be absent, as in the early phase of idiopathic acute eosinophilic pneumonia or when patients are already taking corticosteroids. On bronchoalveolar lavage, high eosinophilia (>25 %, and preferably >40 % of differential cell count) is considered diagnostic of eosinophilic pneumonia in a compatible setting, obviating the need of video-assisted thoracic surgical lung biopsy, which is now performed only on very rare occasions with inconsistency between clinical, biological, and imaging features. Inquiry as to drug intake must be meticulous (www.pneumotox.com) and any suspected drug should be withdrawn. Laboratory investigations for parasitic causes must take into account the travel history or residence and the epidemiology of parasites. In patients with associated extrathoracic manifestations, the diagnosis of eosinophilic granulomatosis with polyangiitis or of the hypereosinophilic syndromes should be raised. Presence of airflow obstruction can be found in hypereosinophilic asthma, allergic bronchopulmonary aspergillosis, idiopathic chronic eosinophilic pneumonia, eosinophilic granulomatosis with polyangiitis, or in the recently identified syndrome of hyperosinophilic obliterative bronchiolitis. Corticosteroids remain the cornerstone of symptomatic treatment for eosinophilic pneumonias, with a generally dramatic response. Relapses are common when tapering the doses or after stopping treatment especially in idiopathic chronic eosinophilic pneumonia. Cyclophosphamide is necessary only in patients with eosinophilic granulomatosis with polyangiitis and poor-prognostic factors. Imatinib is very effective in the treatment of the myeloproliferative variant of hypereosinophilic syndromes. Anti-interleukin-5 monoclonal antibodies are promising in the spectrum of eosinophilic disorders.

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.

Omalizumab in children

Omalizumab is a recombinant humanized monoclonal antibody that reduces levels of circulating immunoglobulin E (IgE) and expression of IgE high-affinity receptors on mast cells and basophils, interrupting the subsequent allergic inflammatory cascade. Current indications for treatment with omalizumab in pediatric patients are clearly defined and are confined to moderate-to-severe uncontrolled allergic asthma and chronic spontaneous urticaria (CSU). Any other prescription can only be off label. Data available from clinical trials conducted in children suggest that omalizumab is clinically effective and generally well tolerated. Given its mechanism of action, recent reports have suggested its possible clinical use in other IgE-mediated disorders, such as allergic rhinitis, food allergy, and anaphylaxis. In recent years, several studies have also investigated the possible applications of omalizumab in a number of non IgE-mediated diseases. The aim of the present review is to assess all applications of omalizumab as therapy in the pediatric population. The approved indications--allergic asthma and CSU--are reviewed. Moreover, further potential applications of omalizumab are discussed in both IgE-mediated and non-IgE-mediated diseases.

Innate Defense against Fungal Pathogens

Human fungal infections have been on the rise in recent years and proved increasingly difficult to treat as a result of the lack of diagnostics, effective antifungal therapies, and vaccines. Most pathogenic fungi do not cause disease unless there is a disturbance in immune homeostasis, which can be caused by modern medical interventions, disease-induced immunosuppression, and naturally occurring human mutations. The innate immune system is well equipped to recognize and destroy pathogenic fungi through specialized cells expressing a broad range of pattern recognition receptors (PRRs). This review will outline the cells and PRRs required for effective antifungal immunity, with a special focus on the major antifungal cytokine IL-17 and recently characterized antifungal inflammasomes.

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.

B lymphocytes regulate airway granulocytic inflammation and cytokine production in a murine model of fungal allergic asthma

Sensitization to fungi often leads to a severe form of asthma that is particularly difficult to manage clinically, resulting in increased morbidity and hospitalizations in these patients. Although B lymphocytes might exacerbate asthma symptoms through the production of IgE, these cells might also be important in the protective response against inhaled fungi. Through cytokine release and T-cell interactions, these lymphocytes might also influence the development and maintenance of airway wall fibrosis. J(H)(-/-) mice lack the JH gene for the heavy chain component of antibodies, which is critical for B-cell function and survival. These animals have facilitated the elucidation of the role of B lymphocytes in a number of immune responses; however, J(H)(-/-) mice have not been used to study fungal allergy. In this study, we examined the role of B lymphocytes using an Aspergillus fumigatus murine fungal aeroallergen model that mimics human airway disease that is triggered by environmental fungal exposure. We compared disease progression in sensitized wild-type BALB/c and J(H)(-/-) mice that were exposed to repeated fungal exposure and found no differences in airway hyperresponsiveness, overall pulmonary inflammation or collagen deposition around the large airways. However, the levels of the Th2-type cytokines IL-4 and IL-13 were significantly attenuated in the airways of J(H)(-/-) mice relative to the BALB/c controls. By contrast, levels of the inflammatory cytokines IL-17A and IL-6 were significantly elevated in the J(H)(-/-) animals, and there was significantly more robust airway eosinophilia and neutrophilia than in control animals. Taken together, these findings demonstrate that B lymphocytes help to regulate granulocytic responses to fungal exposure in the pulmonary compartment.

Emerging novel and antimicrobial-resistant respiratory tract infections: new drug development and therapeutic options

The emergence and spread of antimicrobial-resistant bacterial, viral, and fungal pathogens for which diminishing treatment options are available is of major global concern. New viral respiratory tract infections with epidemic potential, such as severe acute respiratory syndrome, swine-origin influenza A H1N1, and Middle East respiratory syndrome coronavirus infection, require development of new antiviral agents. The substantial rise in the global numbers of patients with respiratory tract infections caused by pan-antibiotic-resistant Gram-positive and Gram-negative bacteria, multidrug-resistant Mycobacterium tuberculosis, and multiazole-resistant fungi has focused attention on investments into development of new drugs and treatment regimens. Successful treatment outcomes for patients with respiratory tract infections across all health-care settings will necessitate rapid, precise diagnosis and more effective and pathogen-specific therapies. This Series paper describes the development and use of new antimicrobial agents and immune-based and host-directed therapies for a range of conventional and emerging viral, bacterial, and fungal causes of respiratory tract infections.

Allergic bronchopulmonary aspergillosis

There remains a lack of agreement on diagnostic criteria and approaches to treatment of patients with allergic bronchopulmonary aspergillosis (ABPA). The results of a survey of American Academy of Allergy, Asthma, & Immunology members regarding these 2 issues are presented and compared for concordance with published recommendations. The literature was reviewed for pertinent reports, and an electronic survey was conducted of American Academy of Allergy, Asthma, & Immunology members and fellows regarding diagnostic criteria, numbers of patients evaluated for ABPA, and treatment approaches. From 508 respondents to the survey sent to 5155 US physicians in the American Academy of Allergy, Asthma, & Immunology database of members and fellows, 245 health professionals (48%) had treated at least 1 patient with ABPA in the previous year. For the diagnosis of ABPA, there was a difference in the threshold concentration of total serum IgE because 44.9% used ≥417 kU/L, whereas 42.0% used ≥1000 kU/L. Analysis of these findings suggests that ABPA might be underdiagnosed. With regard to pharmacotherapy, oral steroids were recommended for 97.1% of patients and oral steroids plus inhaled corticosteroids plus antifungal agent were used with 41.2% of patients. The armamentarium for treatment of ABPA includes oral corticosteroids as the initial treatment with inhaled corticosteroids used for management of persistent asthma. Azoles remain adjunctive. Published experience with omalizumab has been limited.

Infection-related asthma

The role of infection in asthma is varied in that it may exacerbate established asthma or contribute to the initial development of the clinical onset of asthma. Mounting evidence implicates both roles with particular viral pathogens, namely human rhinovirus and respiratory syncytial virus, among the most likely culprits in asthma inception. Once asthma is present, infection, particularly viral infection, is a common precipitant of asthma exacerbations. Bacterial infections and colonization also have been associated with exacerbation and recurrent wheeze, an effect that may be independent or a cofactor with viruses. Atypical bacterial infections such as Mycoplasma pneumoniae and Chlamydia pneumoniae and fungi in the case of allergic bronchopulmonary aspergillosis, also play a potential role in inducing and exacerbating this disease. In addition, certain individuals may have a genetic predisposition toward viral-induced wheezing and the development of asthma. This article will discuss host and environmental factors, common pathogens, clinical characteristic, and genetic influences associated with infection-related asthma.

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.

Antimicrobial treatment of non-cystic fibrosis bronchiectasis

Bronchiectasis unrelated to cystic fibrosis is characterized by chronic wet or productive cough, recurrent exacerbations and irreversible bronchial dilatation. After antibiotics and vaccines became available and living standards in affluent countries improved, its resulting reduced prevalence meant bronchiectasis was considered an 'orphan disease'. This perception has changed recently with increasing use of CT scans to diagnose bronchiectasis, including in those with severe chronic obstructive pulmonary disease or 'difficult to control' asthma, and adds to its already known importance in non-affluent countries and disadvantaged Indigenous communities. Following years of neglect, there is renewed interest in identifying the pathogenetic mechanisms of bronchiectasis, including the role of infection, and conducting clinical trials. This is providing much needed evidence to guide antimicrobial therapy, which has relied previously upon extrapolating treatments used in cystic fibrosis and chronic obstructive pulmonary disease. While many knowledge gaps and management challenges remain, the future is improving for patients with bronchiectasis.

Fungal culture and sensitisation in asthma, cystic fibrosis and chronic obstructive pulmonary disorder: what does it tell us?

Collectively asthma, chronic obstructive pulmonary disorder (COPD) and cystic fibrosis (CF) are very common, important causes of disease and ill health. Filamentous fungal colonisation of the airways can occur in all three disease groups, although the clinical relevance is unclear. Allergic bronchopulmonary aspergillosis (ABPA) is a well-recognised severe complication of airway colonisation associated primarily with Aspergillus fumigatus. Fungal colonisation may have a deleterious effect without fulfilling all the diagnostic criteria of ABPA; however, a lack of standardisation in processing respiratory samples hampers comparisons. Whilst mycology laboratory accreditation programs are common, most countries have no national standard guidelines for processing respiratory samples. Fungal recovery from sputum in CF, asthma and COPD can be around 40, 54 and 49%, respectively. Isolation of fungi from sputum has been associated with reduced lung function in asthma and CF, although no such associations have been found in COPD. It is unclear whether fungal colonisation contributes to lower lung function or is a marker of more severe lung disease and aggressive therapy. Fungal sensitisation may contribute to the persistence of active respiratory symptoms; however, the exact prevalence is unclear. Sensitisation to A. fumigatus has been associated with reduced lung function in asthma, COPD and CF. It has suggested that both skin prick tests and specific IgE measurement by the ImmunoCAP system should be used in diagnoses of allergy, due to discordance in test results; however, there is currently no widely adopted consensus as to which fungi to test for.

A questionnaire-based study on the role of environmental factors in allergic bronchopulmonary aspergillosis

Background and Aims:

Allergic bronchopulmonary aspergillosis (ABPA) is an immunological disorder caused by hypersensitivity against Aspergillus fumigatus. The pathogenesis of ABPA remains unknown. Few studies have investigated the role of environmental factors in pathogenesis of ABPA. Herein, we investigate the role of environmental factors in ABPA.

Materials and Methods:

In this prospective case-control study, consecutive patients with asthma (Aspergillus sensitized and unsensitized) and ABPA were investigated using a standardized questionnaire to enquire into their demographic characteristics, clinical details, exposure to organic matter and living conditions (home environment, presence of moisture in the walls, and others). Asthma severity and control was assessed using the 2002 The Global Initiative for Asthma (GINA) recommendations and asthma control test, respectively.

Results:

During the study period, 202 subjects of asthma (103 and 99 Aspergillus unsensitized and sensitized asthma, respectively) and 101 ABPA with a mean (SD) age of 35.3 (14.7) years were included. The baseline characteristics were similar in the two groups except for a higher prevalence of severe persistent asthma in the ABPA group (79% vs. 44%, P = 0.0001). No significant differences in environmental factors were noted in the ABPA population compared to asthmatic patients except for a higher rural residence in ABPA (47% vs. 66%, P = 0.007).

Conclusions:

The study found no significant environmental differences in ABPA compared to asthmatic patients. It is likely that environmental factors are not the primary pathogenetic factors in causation of ABPA.

Miliary nodules: An unusual presentation of allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is an immune-mediated inflammatory disease caused by hypersensitivity to Aspergillus fumigatus. A wide spectrum of plain radiographic appearances has been described in ABPA, though none are pathognomonic of ABPA. The common radiological abnormalities encountered are fleeting pulmonary opacities, bronchiectasis, and mucoid impaction. Uncommon radiological findings encountered in ABPA include pulmonary masses, perihilar opacities simulating hilar adenopathy, and pleural effusions. However, miliary nodules as a radiological presentation of ABPA are very rare and only one case has been reported in literature. It is often misdiagnosed and mismanaged as tuberculosis; thus, the clinician should be vigilant enough to diagnose this very rare entity.

The mycobiota: interactions between commensal fungi and the host immune system

The body is host to a wide variety of microbial communities from which the immune system protects us and that are important for the normal development of the immune system and for the maintenance of healthy tissues and physiological processes. Investigators have mostly focused on the bacterial members of these communities, but fungi are increasingly being recognized to have a role in defining these communities and to interact with immune cells. In this Review, we discuss what is currently known about the makeup of fungal communities in the body and the features of the immune system that are particularly important for interacting with fungi at these sites.

Screening-based discovery of Aspergillus fumigatus plant-type chitinase inhibitors

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We performed a high-throughput screen of 60,000 compounds against A. fumigatus chitinase A1.

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Novel low micromolar competitive inhibitors were identified.

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These represent the most potent selective plant-type A. fumigatus chitinase inhibitors to date.

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We provide new tools for probing chitinase inhibition in A. fumigatus and other fungi.

A limited therapeutic arsenal against increasing clinical disease due to Aspergillus spp. necessitates urgent characterisation of new antifungal targets. Here we describe the discovery of novel, low micromolar chemical inhibitors of Aspergillus fumigatus family 18 plant-type chitinase A1 (AfChiA1) by high-throughput screening (HTS). Analysis of the binding mode by X-ray crystallography confirmed competitive inhibition and kinetic studies revealed two compounds with selectivity towards fungal plant-type chitinases. These inhibitors provide new chemical tools to probe the effects of chitinase inhibition on A. fumigatus growth and virulence, presenting attractive starting points for the development of further potent drug-like molecules.

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.

Multi-country estimate of different manifestations of aspergillosis in cystic fibrosis

Aspergillus spp. can lead to allergic bronchopulmonary aspergillosis (ABPA), Aspergillus sensitisation and Aspergillus bronchitis in CF. The relative frequencies of these entities have recently been ascertained in a large UK adult CF cohort. We have used this data to estimate the burden of aspergillosis and ABPA cases in adult CF patients in 30 countries reporting CF. National and international CF registry data was accessed and assessed for completeness and age distribution. Published proportions of ABPA (17.7%), Aspergillus sensitisation (14.6%) and Aspergillus bronchitis (30%) in CF were applied to those >18 years and compared with notified ABPA cases. Of the 76,201 estimated CF patients worldwide (not including India), 37,714 were >18 years. The proportion of adults to children varied from 63% in Norway to 20% in Brazil. ABPA caseload in adults is anticipated to be 6,675 cases of which only 2,221 cases (33%) are currently recorded, indicating substantial underdiagnosis. The ABPA diagnosis rate compared with estimated rates varies by country from 101% (France) to 14.5% (Greece), although genetic variation could account for genuine differences compared with the UK. Aspergillus bronchitis is not currently recognised or recorded in CF registries but there are an anticipated 10,988 adult cases. Aspergillus sensitisation, associated with increased bronchiectasis and reduced FEV1, affects an anticipated 5,506 patients without ABPA or Aspergillus bronchitis. Together ABPA and Aspergillus bronchitis are estimated to affect 17,989 adults, 47.7% of the adult CF population. ABPA also occurs in children and teenagers and 984 cases were documented in registries. Diagnosed ABPA rates by age were available for the ECFS registry, USA, UK, Ireland, Belgium and Netherlands. The rate was <1% under 4 years, and increased throughout childhood and adolescence, with marked variation between countries. Newly published diagnostic criteria and methods should facilitate better recognition of aspergillosis in CF, allowing better CF disease control.

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

Allergic bronchopulmonary aspergillosis (ABPA) is a complex pulmonary disorder caused by immunologic reactions to antigens released by Aspergillus fumigatus, a ubiquitous fungi colonizing the tracheobronchial tree of asthmatic patients. The clinical presentation is usually poorly controlled asthma, recurrent pulmonary opacities and bronchiectasis. The prevalence of ABPA in asthma clinics may be as high as 13% with a global burden of almost 5 million patients. A. fumigatus-specific IgE level is the most sensitive test in diagnosis of ABPA, and all asthmatic patients should be routinely screened with A. fumigatus-specific IgE levels for early diagnosis. The goals of managing ABPA include control of asthma, prevention and treatment of acute exacerbations, and preventing the development or progression of bronchiectasis. Glucocorticoids are the treatment of choice with itraconazole reserved for those with recurrent exacerbations and glucocorticoid-dependent disease. There is a dire need for newer treatment approaches including oral antifungal agents and immunomodulatory therapy.

Fungal allergy in asthma-state of the art and research needs

Sensitization to fungi and long term or uncontrolled fungal infection are associated with poor control of asthma, the likelihood of more severe disease and complications such as bronchiectasis and chronic pulmonary aspergillosis. Modelling suggests that >6.5 million people have severe asthma with fungal sensitizations (SAFS), up to 50% of adult asthmatics attending secondary care have fungal sensitization, and an estimated 4.8 million adults have allergic bronchopulmonary aspergillosis (ABPA). There is much uncertainty about which fungi and fungal allergens are relevant to asthma, the natural history of sensitisation to fungi, if there is an exposure response relationship for fungal allergy, and the pathogenesis and frequency of exacerbations and complications. Genetic associations have been described but only weakly linked to phenotypes. The evidence base for most management strategies in ABPA, SAFS and related conditions is weak. Yet straightforward clinical practice guidelines for management are required. The role of environmental monitoring and optimal means of controlling disease to prevent disability and complications are not yet clear. In this paper we set out the key evidence supporting the role of fungal exposure, sensitisation and infection in asthmatics, what is understood about pathogenesis and natural history and identify the numerous areas for research studies.