T cell proliferation and cytokine secretion to T cell epitopes of Asp f 2 in ABPA patients

The Use of Targeted Monoclonal Antibodies in the Treatment of ABPA—A Case Series

Allergic bronchopulmonary aspergillosis (ABPA) is a pulmonary disorder occurring in response to Aspergillus fumigatus that can complicate the course of asthma and cystic fibrosis. Here we present a case of acute ABPA without central bronchiectasis, a case of chronic active ABPA with central bronchiectasis, and a case of severe relapsing ABPA with central bronchiectasis. All three were initially treated with corticosteroids and antifungal agents but had an incomplete response. These patients were then treated with anti-IgE therapy with omalizumab before being switched to the anti-IL5R agent benralizumab. They responded well to both agents. These case reports highlight the potential role of omalizumab and benralizumab in the treatment of ABPA, but further studies are required to evaluate the effectiveness of these medications. Longer follow-up periods and objective measurements of the impact of treatment are necessary.

An overview of possible pathogenesis mechanisms of Alternaria alternata in chronic rhinosinusitis and nasal polyposis

Chronic Rhinosinusitis (CRS) is a multifactorial disease, and different etiologies like metabolism and immunity disorders, bacterial superantigens, biofilms, and fungal allergens are known to develop this disease, especially the CRS with nasal polyps. Alternaria alternata (Alternaria) is one of the most prevalent airborne fungal species in the nasal discharge, which might have vigorous immunologic activities in nasal epithelial cells and play an essential role in the pathogenesis of CRS. Moreover, the interaction between this fungus and the innate and adaptive immune systems leads to the development of chronic inflammation. This inflammation may consequently instigate the CRS and nasal polyposis. The attenuation of surfactant protein synthesis or intracellular reserves and mucus hypersecretion could prevent the clearance of Alternaria from sinuses and may be correlated with colonization and re-infection of airborne fungi. Furthermore, higher expression of cathelicidin, thymic stromal lymphopoietin, toll-like receptors, and T helper 2-dominant immune responses can result in an IgE-mediated pathway activation and eosinophils degranulation. Moreover, higher local Alternaria-specific IgE was shown to be correlated with eosinophilic cationic proteins and might relate to nasal polyps. However, the role of genetic and environmental factors affecting CRS and nasal polyposis is not well studied. Likewise, further animal and clinical studies are required to better understand the role of Alternaria in CRS disease. The current article reviews the recent findings around the Alternaria-induced CRS and nasal polyposis.

Differential response to biologics in a patient with severe asthma and ABPA: a role for dupilumab?

Background

Allergic bronchopulmonary aspergillosis (ABPA) is a severe hypersensitivity reaction to aspergillus species colonizing the airways of patients with asthma or cystic fibrosis. Biologics including anti-IgE and anti-IL5 antibodies have strongly changed the treatment of severe asthmatics and have partly been reported to be effective in the treatment of ABPA. Recently, dupilumab, an anti-IL4-Rα antibody which inhibits signaling by the Th2-cytokines IL4 and IL13, has been approved for the treatment of severe asthma.

Case presentation

Here, we report the case of a 49-year-old woman with severe asthma and ABPA, who was uncontrolled despite maximum inhalative therapy, anti-IL5-Rα antibody and continuous oral steroid therapy. Moreover, trials of itraconazole as well as omalizumab showed insufficient efficacy. Lung function revealed peripheral obstruction. FeNO and IgE were increased, eosinophils were suppressed under treatment while marked increases had been documented previously. Switching to dupilumab led to a complete resolution of pulmonary symptoms, resolution of exacerbations and complete withdrawal of oral steroids. A drastic improvement in lung function was noted, with an increase in FEV1 of almost 1 l. FeNO was normalized and IgE strongly reduced.

Conclusion

Our case highlights that a patient may exhibit differential treatment responses to the currently available asthma biologics and suggests switching treatment if outcome is insufficient. A potential role for dupilumab in the treatment of ABPA warrants future studies.

A case of allergic bronchopulmonary aspergillosis successfully treated with mepolizumab

Background

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic pulmonary disease comprising a complex hypersensitivity reaction to Aspergillus fumigatus. Clinical features of ABPA are wheezing, mucoid impaction, and pulmonary infiltrates. Oral corticosteroids and anti-fungal agents are standard therapy for ABPA, but long-term use of systemic corticosteroids often causes serious side effects.

Case presentation

A 64-year-old woman was diagnosed with ABPA based on a history of bronchial asthma (from 40 years of age), elevated total IgE, the presence of serum precipitating antibodies and elevated specific IgE antibody to A. fumigatus, and pulmonary infiltration. Bronchoscopy showed eosinophilic mucoid impaction. Systemic corticosteroid therapy was initiated, and her symptoms disappeared. Peripheral eosinophilia and pulmonary infiltration recurred five months after cessation of corticosteroid treatment. Systemic corticosteroids were re-initiated and itraconazole was added as an anti-fungal agent. The patient was free of corticosteroids, aside from treatment with a short course of systemic corticosteroids for asthma exacerbation, and clinically stable with itraconazole and asthma treatments for 3 years. In 2017, she experienced significant deterioration. Laboratory examination revealed marked eosinophilia (3017/μL) and a chest computed tomography (CT) scan demonstrated pulmonary infiltration in the left upper lobe and mucoid impaction in both lower lobes. The patient was treated with high-dose inhaled corticosteroid/long-acting beta-agonist, a long-acting muscarinic antagonist, a leukotriene receptor antagonist, and theophylline; spirometry revealed a forced expiratory volume in 1 s (FEV₁) of 1.01 L. An uncontrolled asthma state was indicated by an Asthma Control Test (ACT) score of 18. Mepolizumab, 100 mg every 4 weeks, was initiated for the treatment of severe bronchial asthma with ABPA exacerbation. Bronchial asthma symptoms dramatically improved, and ACT score increased to 24, by 4 weeks after mepolizumab treatment. Peripheral eosinophil count decreased to 174/μL. Spirometry revealed improvement of lung function (FEV₁: 1.28 L). A chest CT scan demonstrated the disappearance of pulmonary infiltration and mucoid impaction.

Conclusions

To our knowledge, this is the first case of ABPA to be treated with mepolizumab. Dramatic improvements were observed in symptoms, lung function, peripheral eosinophil counts, and chest images. Mepolizumab could serve as an alternative treatment with the potential to provide a systemic corticosteroid-sparing effect.

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.

T helper 2 response in allergic bronchopulmonary aspergillosis is not driven by specific Aspergillus antigens

Allergic bronchopulmonary aspergillosis (ABPA) is characterized by an allergic immunological response to Aspergillus fumigatus. In this study, we investigated whether certain Aspergillus antigens are more allergenic than others, as was postulated previously. We stimulated peripheral blood mononuclear cells from patients with ABPA with the classically described A. fumigatus allergens Aspf1, Aspf2, Aspf3, and Aspf4, as well as two other Aspergillus antigens, Crf1 and Catalase1. Activated CD4+ T cells displayed a T helper 2 phenotype with the production of IL-4 in response to stimulation with several of these different antigens. Immune responses were not limited to the classically described A. fumigatus allergens. In healthy individuals, we demonstrated a similar recognition profile to the different antigens, but in contrast the activated CD4+ T cells exerted a T helper 1 phenotype and mainly produced IFN-γ after stimulation with A. fumigatus antigens. In conclusion, irrespective of the A. fumigatus antigen, the T-cell immune response in patients with ABPA is skewed to a T helper 2 cytokine secretion profile.

Recurrent allergic bronchopulmonary aspergillosis in a patient with rheumatoid arthritis treated with etanercept and tocilizumab

We report the case of a 68-year-old woman with Stage III and Class II rheumatoid arthritis (RA) that was resistant to prednisolone, methotrexate, and infliximab. After treatment with etanercept or tocilizumab, suspicious allergic bronchopulmonary aspergillosis (ABPA) repeatedly occurred and then rapidly improved after the withdrawal of each drug. We suspect that administration of etanercept and tocilizumab caused suspicious ABPA in this patient. The relevance to the pathogenesis of ABPA under these biological drugs is also discussed.

Peripheral Blood Mononuclear Cells from Allergic Fungal Rhinosinusitis Adults Express a Th2 Cytokine Response to Fungal Antigens

Background

The etiology of allergic fungal rhinosinusitis (AFRS) remains controversial. Initially thought to represent an immunoglobulin E (IgE)–mediated hypersensitivity to fungal antigens, additional data have implicated other non-IgE and cellular-mediated pathways. The aim of this study was to characterize T-helper type 1 (Th1) and Th2 immune responses of blood lymphocytes from AFRS patients by fungal antigen stimulation to help differentiate these possible pathways.

Methods

Peripheral blood mononuclear cells (PBMCs) isolated from AFRS patients (n = 10) and healthy controls (HCs; n = 11) were exposed to four different fungal extracts (Alternaria, Aspergillus, Cladosporium, and Penicillium) in duplicate. After a 72-hour incubation, the supernatants were analyzed for cytokine levels of three Th1 (interferon [IFN] gamma, interleukin [IL]-2, and tumor necrosis factor alpha) and three Th2 (IL-10, IL-5, and IL-4) cytokines by cytometric bead array flow cytometry. Serum fungal-specific IgE levels were measured by ImmunoCAP (Pharmacia Diagnostics, Kalamazoo, MI).

Results

Fungal extracts of Alternaria and Cladosporium stimulated higher levels of IL-5 from PBMCs in AFRS when compared with HCs (p < 0.05). IL-4 was also elevated for Alternaria in AFRS versus HCs (p < 0.05). A skewed Th2 response to fungal antigen exposure was confirmed by an elevated IL-5/IFN-gamma ratio in AFRS subjects (p < 0.05). Initial studies suggest a correlation between percent T-cell activation and IL-5 expression to IgE levels. Fungal antigens stimulated a notable but not statistically significant increase in IL-10 response in HCs.

Conclusion

In AFRS patients, fungal antigens stimulated T-cell activation, inducing a predominately Th2 immune response. Healthy controls expressed an inhibitory cytokine IL-10 when exposed to these fungal antigens, possibly serving as a protective response.

Immunological mechanisms behind the cystic fibrosis-ABPA link

Allergic bronchopulmonary aspergillosis (ABPA), a pulmonary hypersensitivity disease mediated by an allergic response to Aspergillus fumigatus (A. fumigatus), occurs preferentially in disease conditions with an impaired pulmonary immunity, especially in cystic fibrosis (CF) and allergic asthma. The pathophysiological mechanisms underlying the link between CF and ABPA are poorly understood. Animal and human data support a critical role for chemokines, especially CCL17 and its receptor CCR4, in ABPA. A summary and discussion of the immunological mechanism involved in the pathogenesis of ABPA with a focus on CF lung disease and the role of chemokines is presented here.

The spectrum of fungal allergy

Fungi can be found throughout the world. They may live as saprophytes, parasites or symbionts of animals and plants in indoor as well as outdoor environment. For decades, fungi belonging to the ascomycota as well as to the basidiomycota have been known to cause a broad panel of human disorders. In contrast to pollen, fungal spores and/or mycelial cells may not only cause type I allergy, the most prevalent disease caused by molds, but also a large number of other illnesses, including allergic bronchopulmonary mycoses, allergic sinusitis, hypersensitivity pneumonitis and atopic dermatitis; and, again in contrast to pollen-derived allergies, fungal allergies are frequently linked with allergic asthma. Sensitization to molds has been reported in up to 80% of asthmatic patients. Although research on fungal allergies dates back to the 19th century, major improvements in the diagnosis and therapy of mold allergy have been hampered by the fact that fungal extracts are highly variable in their protein composition due to strain variabilities, batch-to-batch variations, and by the fact that extracts may be prepared from spores and/or mycelial cells. Nonetheless, about 150 individual fungal allergens from approximately 80 mold genera have been identified in the last 20 years. First clinical studies with recombinant mold allergens have demonstrated their potency in clinical diagnosis. This review aims to give an overview of the biology of molds and diseases caused by molds in humans, as well as a detailed summary of the latest results on recombinant fungal allergens.

The costimulatory molecules CD80, CD86 and OX40L are up-regulated in Aspergillus fumigatus sensitized mice

Aspergillus fumigatus (Af) is a fungus associated with allergic bronchopulmonary aspergillosis (ABPA) and other allergic diseases. Immune responses in these diseases are due to T and B cell responses. T cell activation requires both Af-specific engagement of the T-cell-receptor as well as interaction of antigen independent costimulatory molecules including CD28-CD80/CD86 and OX40-OX40L interactions. Since these molecules and their interactions have been suggested to have a potential involvement in the pathogenesis of ABPA, we have investigated their role in a model of experimental allergic aspergillosis. BALB/c mice were primed and sensitized with Af allergens, with or without exogenous IL-4. Results showed up-regulation of both CD86 and CD80 molecules on lung B cells from Af-sensitized mice (79% CD86+ and 24% CD80+) and Af/rIL-4-treated mice (90% CD86+ and 24% CD80+) compared to normal controls (36% and 17%, respectively). Lung macrophages in Af-sensitized mice treated or not with IL-4 showed enhanced expression of these molecules. OX40L expression was also up-regulated on lung B cells and macrophages from both Af-sensitized and Af/rIL-4 exposed mice as compared to normal controls. All Af-sensitized animals showed peripheral blood eosinophilia, enhanced total serum IgE and allergen-specific IgG1 antibodies and characteristic lung inflammation. The up-regulation of CD80, CD86 and OX40L molecules on lung B cells and macrophages from Af-allergen exposed mice suggests a major role for these molecules in the amplification and persistence of immunological and inflammatory responses in ABPA.

Aspergillus antigens: which are important?

Aspergillus fumigatus is a ubiquitous fungus that causes a variety of diseases in man and animals. A number of protein, carbohydrate, and glycoprotein antigens have been identified from A. fumigatus. The diseases are diverse, and therefore are the antigens and their roles in causing or modulating the diseases. The induction and binding of antibodies and the interaction of antigen and various immune cells are of immense significance in the diagnosis and prognosis of the disease. In recent years, over 20 genes encoding A. fumigatus antigens have been cloned and the proteins expressed. Among these allergens, Asp f 1, f 2, f 3, f 4, and f 6 showed strong but diverse IgE binding with sera from different groups of patients. Results currently available suggest that Asp f 2, f 3, and f 6 together reacted with IgE from more patients with asthma and allergic bronchopulmonary aspergillosis (ABPA), although they are only marginally effective in demonstrating specific IgE in patients with cystic fibrosis and ABPA. The molecular structure of allergens also plays a major role in the immunological response in the allergic patients. Antigens can be engineered with less or more binding with IgE, and such antigens may have significant roles as specific reagents or as immunomodulators.

Generation of Th1 T cell responses directed to a HLA Class II restricted epitope from the Aspergillus f16 allergen

The Aspergillus allergen Asp f16 has been shown to confer protective Th1 T cell-mediated immunity against infection with Aspergillus conidia in murine models. Here, we use overlapping (11-aa overlap with preceding peptide) pentadecapeptides spanning the entire 427-aa coding region of Asp f16 presented on autologous dendritic cells (DC) to evaluate the ability of this antigen to induce Th1 responses in humans. Proliferative responses were induced in five out of five donors, and one line with a high frequency of interferon (IFN)-gamma-producing CD4(+) T cells in response to the complete peptide pool was characterized. This line was cytotoxic to autologous pool-pulsed and Aspergillus culture extract-pulsed targets. Limitation of cytotoxicity to the CD4(+) T cell subset was demonstrated by co-expression of the degranulation marker CD107a in response to peptide pool-pulsed targets. Cytotoxic T lymphocytes (CTL) killed Aspergillus hyphae and CTL culture supernatant killed Aspergillus conidia. By screening 21 smaller pools and individual peptides shared by positive pools we identified a single candidate sequence of TWSIDGAVVRT that elicited responses equal to the complete pool. The defined epitope was presented by human leucocyte antigen (HLA)-DRB1-0301. These data identify the first known Aspergillus-specific T cell epitope and support the use of Asp f16 in clinical immunotherapy protocols to prime protective immune responses to prevent or treat Aspergillus infection in immunocompromised patients.

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.

Fungal allergens

Many fungi are capable of causing IgE-mediated hypersensitivity in humans. However, the most predominant fungi implicated in allergy belong to the genera Aspergillus, Alternaria, Cladosporium, and Penicillium. Pure and relevant allergens are essential for diagnosis as well as for understanding the immunopathogenesis of the disease. Until recently, pure and standardizable antigens from fungi were not available. In recent years, many recombinant allergens have been produced by molecular cloning. Using these allergens, novel methods are being developed to improve diagnosis of mold-induced allergy. By understanding the immunopathogenesis of allergens, new avenues might open up leading to improved patient care, including immunotherapy and vaccination. This review covers the current status of fungal allergens, their role in reliable immunodiagnosis, and their probable use in immunotherapy and vaccination.

C-terminal cysteine residues determine the IgE binding of Aspergillus fumigatus allergen Asp f 2

The knowledge of the structure function relationship of the allergen is essential to design allergenic variants with reduced IgE binding capacity but intact T cell reactivity. Asp f 2 is a major allergen from the fungus Aspergillus fumigatus and >90% of A. fumigatus-sensitized individuals displayed IgE binding to Asp f 2. In the present study, we evaluated the involvement of C-terminal cysteine residues in IgE binding conformation of Asp f 2. The deletion mutants were constructed by adding three C-terminal cysteines of the native Asp f 2 one at a time to the non-IgE binding Asp f 2 (68-203). The point mutants of Asp f 2 (68-268) with C204A and C257A substitutions were constructed to study the role of C-terminal cysteines in IgE binding. Immunological evaluation of reduced and alkylated Asp f 2 and its mutants were conducted to determine the contribution of free sulfhydryl groups as well as the disulfide bonds in allergen Ab interaction. Four-fold increase in IgE Ab binding of Asp f 2 (68-267) compared with Asp f 2 (68-266) and complete loss in IgE binding of C204A mutant of Asp f 2 (68-268) indicate the involvement of C(204) and C(267) in IgE binding conformation of Asp f 2. A significant reduction in IgE binding of wild and mutated Asp f 2 after reduction and alkylation emphasizes the importance of cysteine disulfide bonds in epitope Ab interaction. The hypoallergenic variants may be explored further to develop safe immunotherapeutic strategy for allergic disorders.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) complicates asthma and cystic fibrosis. The survival factors in Aspergillus fumigatus that support saprophytic growth in bronchial mucus are not understood. Prednisone remains the most definitive treatment but need not be administered indefinitely. MHC II -restricted CD4(+) T( H)2 clones have been derived from patients with ABPA. The total serum IgE concentration is elevated sharply but is "nonspecific. " IgE serum isotypic antibodies to A fumigatus are useful in diagnosis; this is in contrast to the situation for patients with asthma without ABPA. High-resolution computed tomography of the chest demonstrates multiple areas of bronchiectasis in most patients with ABPA and is a useful radiologic tool. Some asthma control patients might have a few bronchiectatic airways, but not to the extent seen in or of the same character as those in ABPA. This review discusses clinical, radiologic, investigational, pathogenetic, and treatment issues of ABPA.

Immunobiology of fungal allergens

In recent years, considerable attention has been paid in obtaining purified relevant allergens from fungi associated with allergy. Using molecular biology techniques, a number of mold allergens have been obtained by cloning the genes encoding the allergens. Currently, about 70 fungal allergens have been approved by the International Allergen Nomenclature Committee. In this review, we have presented major allergens from Aspergillus, Penicillium, Cladosporium, and Alternaria and discussed their immunochemical characteristics and their role in the diagnosis of allergy and possible usefulness in understanding the pathogenesis of the disease. The structure-function properties and the potential role of these recombinant allergens in the immunomodulatory therapy also are presented.