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Chotirmall SH, Chalmers JD. The Precision Medicine Era of Bronchiectasis. Am J Respir Crit Care Med 2024; 210:24-34. [PMID: 38949497 PMCID: PMC11197062 DOI: 10.1164/rccm.202403-0473pp] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 04/10/2024] [Indexed: 07/02/2024] Open
Affiliation(s)
- Sanjay H. Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore, Singapore; and
| | - James D. Chalmers
- Division of Molecular and Clinical Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee, United Kingdom
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Guo J, Tian W, Lin H, Hu L, Gao X, Xia J, Yu H, Chen H, Li W, Wu W. Analytical and clinical validation of multiplex droplet digital PCR assay for detecting pathogenic fungal infection in lungs. Mycology 2023; 15:110-119. [PMID: 38558836 PMCID: PMC10976995 DOI: 10.1080/21501203.2023.2296941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 12/14/2023] [Indexed: 04/04/2024] Open
Abstract
Pulmonary invasive fungal infection in immunocompromised hosts is difficult to diagnose, and current tools for diagnosis or monitoring of response to antifungal treatments have inherent limitations. Droplet digital PCR (ddPCR) has emerged as a promising tool for pulmonary pathogen detection with high sensitivity. This study presents a novel ddPCR panel for rapid and sensitive identification of pulmonary fungal pathogens. First, a ddPCR method for detecting three fungal genera, including Pneumocystis, Aspergillus, and Cryptococcus, was established and evaluated. Then, the clinical validation performance of ddPCR was compared with that of qPCR using 170 specimens, and the 6 specimens with inconsistent results were further verified by metagenomics next-generation sequencing, which yielded results consistent with the ddPCR findings. Finally, the area under the ROC curve (AUC) was used to evaluate the efficiency of ddPCR. While the qPCR identified 16 (9.41%) cases of Aspergillus and 6 (3.53%) cases of Pneumocystis, ddPCR detected 20 (11.76%) Aspergillus cases and 8 (4.71%) Pneumocystis cases. The AUC for Aspergillus, Cryptococcus, and Pneumocystis was 0.974, 0.998, and 0.975, respectively. These findings demonstrated that the ddPCR assay is a highly sensitive method for identifying pathogens responsible for invasive fungal pulmonary infections, and is a promising tool for early diagnosis. .
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Affiliation(s)
- Jian Guo
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
- School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Wenjie Tian
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Huiping Lin
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Liang Hu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xuejuan Gao
- Pilot Gene Technologies Company Limited, Hangzhou, China
| | - Jiang Xia
- Pilot Gene Technologies Company Limited, Hangzhou, China
| | - Hao Yu
- Pilot Gene Technologies Company Limited, Hangzhou, China
| | - Hui Chen
- Department of Laboratory Medicine, Jiangxi Provincial People’s Hospital Affiliated to Nanchang University, Nanchang, China
| | - Wei Li
- Department of Clinical Laboratory, Qilu Hospital of Shandong University, Jinan, China
| | - Wenjuan Wu
- Department of Laboratory Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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Martins M, Keir HR, Chalmers JD. Endotypes in bronchiectasis: moving towards precision medicine. A narrative review. Pulmonology 2023; 29:505-517. [PMID: 37030997 DOI: 10.1016/j.pulmoe.2023.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 03/10/2023] [Accepted: 03/13/2023] [Indexed: 04/09/2023] Open
Abstract
Bronchiectasis is a highly complex entity that can be very challenging to investigate and manage. Patients are diverse in their aetiology, symptoms, risk of complications and outcomes. "Endotypes"- subtypes of disease with distinct biological mechanisms, has been proposed as a means of better managing bronchiectasis. This review discusses the emerging field of endotyping in bronchiectasis. We searched PubMed and Google Scholar for randomized controlled trials (RCT), observational studies, systematic reviews and meta-analysis published from inception until October 2022, using the terms: "bronchiectasis", "endotypes", "biomarkers", "microbiome" and "inflammation". Exclusion criteria included commentaries and non-English language articles as well as case reports. Duplicate articles between databases were initially identified and appropriately excluded. Studies identified suggest that it is possible to classify bronchiectasis patients into multiple endotypes deriving from their co-morbidities or underlying causes to complex infective or inflammatory endotypes. Specific biomarkers closely related to a particular endotype might be used to determine response to treatment and prognosis. The most clearly defined examples of endotypes in bronchiectasis are the underlying causes such as immunodeficiency or allergic bronchopulmonary aspergillosis where the underlying causes are clearly related to a specific treatment. The heterogeneity of bronchiectasis extends, however, far beyond aetiology and it is now possible to identify subtypes of disease based on inflammatory mechanisms such airway neutrophil extracellular traps and eosinophilia. In future biomarkers of host response and infection, including the microbiome may be useful to guide treatments and to increase the success of randomized trials. Advances in the understanding the inflammatory pathways, microbiome, and genetics in bronchiectasis are key to move towards a personalized medicine in bronchiectasis.
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Affiliation(s)
- M Martins
- Pulmonology Department, Centro Hospitalar Universitário de São João, Porto, Portugal.
| | - H R Keir
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, Dundee, DD1 9SY, Scotland, United Kinkdom
| | - J D Chalmers
- Division of Molecular and Clinical Medicine, Ninewells Hospital and Medical School, Dundee, DD1 9SY, Scotland, United Kinkdom
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Chalmers JD, Elborn S, Greene CM. Basic, translational and clinical aspects of bronchiectasis in adults. Eur Respir Rev 2023; 32:230015. [PMID: 37286220 PMCID: PMC10245133 DOI: 10.1183/16000617.0015-2023] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/03/2023] [Indexed: 06/09/2023] Open
Abstract
Bronchiectasis is a common progressive respiratory disease with recognisable radiological abnormalities and a clinical syndrome of cough, sputum production and recurrent respiratory infections. Inflammatory cell infiltration into the lung, in particular neutrophils, is central to the pathophysiology of bronchiectasis. Herein we explore the roles and relationships between infection, inflammation and mucociliary clearance dysfunction in the establishment and progression of bronchiectasis. Microbial and host-mediated damage are important processes underpinning bronchiectasis and the relative contribution of proteases, cytokines and inflammatory mediators to the propagation of inflammation is presented. We also discuss the emerging concept of inflammatory endotypes, defined by the presence of neutrophilic and eosinophilic inflammation, and explore the role of inflammation as a treatable trait. Current treatment for bronchiectasis focuses on treatment of underlying causes, enhancing mucociliary clearance, controlling infection and preventing and treating complications. Data on airway clearance approaches via exercise and mucoactive drugs, pharmacotherapy with macrolides to decrease exacerbations and the usefulness of inhaled antibiotics and bronchodilators are discussed, finishing with a look to the future where new therapies targeting host-mediated immune dysfunction hold promise.
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Affiliation(s)
| | - Stuart Elborn
- School of Medicine, Dentistry and Biomedical Sciences, Belfast, UK
| | - Catherine M Greene
- Lung Biology Group, Department of Clinical Microbiology, RCSI University of Medicine and Heath Sciences, Education and Research Centre, Beaumont Hospital, Dublin, Ireland
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Di Francesco AM, Verrecchia E, Manna S, Urbani A, Manna R. The chitinases as biomarkers in immune-mediate diseases. Clin Chem Lab Med 2022:cclm-2022-0767. [DOI: 10.1515/cclm-2022-0767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 11/15/2022] [Indexed: 12/12/2022]
Abstract
Abstract
The role of chitinases has been focused as potential biomarkers in a wide number of inflammatory diseases, in monitoring active disease state, and predicting prognosis and response to therapies. The main chitinases, CHIT1 and YKL-40, are derived from 18 glycosyl hydrolases macrophage activation and play important roles in defense against chitin-containing pathogens and in food processing. Moreover, chitinases may have organ- as well as cell-specific effects in the context of infectious diseases and inflammatory disorders and able to induce tissue remodelling. The CHIT1 measurement is an easy, reproducible, reliable, and cost-effective affordable assay. The clinical use of CHIT1 for the screening of lysosomal storage disorders is quite practical, when proper cut-off values are determined for each laboratory. The potential of CHIT1 and chitinases has not been fully explored yet and future studies will produce many surprising discoveries in the immunology and allergology fields of research. However, since the presence of a null CHIT1 gene in a subpopulation would be responsible of false-negative values, the assay should be completed with the other markers such ACE and, if necessary, by genetic analysis when CHIT1 is unexpected low.
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Affiliation(s)
- Angela Maria Di Francesco
- Periodic Fever and Rare Diseases Research Centre, Catholic University of Sacred Heart , Rome , Italy
| | - Elena Verrecchia
- Periodic Fever and Rare Diseases Research Centre, Catholic University of Sacred Heart , Rome , Italy
| | - Stefano Manna
- Periodic Fever and Rare Diseases Research Centre, Catholic University of Sacred Heart , Rome , Italy
| | - Andrea Urbani
- Institute of Internal Medicine, Policlinico A. Gemelli Foundation IRCCS , Rome , Italy
- Department of Chemistry, Biochemistry and Molecular Biology , Policlinico A. Gemelli Foundation IRCCS , Rome , Italy
| | - Raffaele Manna
- Periodic Fever and Rare Diseases Research Centre, Catholic University of Sacred Heart , Rome , Italy
- Institute of Internal Medicine, Policlinico A. Gemelli Foundation IRCCS , Rome , Italy
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Tiew PY, Thng KX, Chotirmall SH. Clinical Aspergillus Signatures in COPD and Bronchiectasis. J Fungi (Basel) 2022; 8:jof8050480. [PMID: 35628736 PMCID: PMC9146266 DOI: 10.3390/jof8050480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 04/30/2022] [Accepted: 05/03/2022] [Indexed: 12/21/2022] Open
Abstract
Pulmonary mycoses remain a global threat, causing significant morbidity and mortality. Patients with airways disease, including COPD and bronchiectasis, are at increased risks of pulmonary mycoses and its associated complications. Frequent use of antibiotics and corticosteroids coupled with impaired host defenses predispose patients to fungal colonization and airway persistence, which are associated with negative clinical consequences. Notably, Aspergillus species remain the best-studied fungal pathogen and induce a broad spectrum of clinical manifestations in COPD and bronchiectasis ranging from colonization and sensitization to more invasive disease. Next-generation sequencing (NGS) has gained prominence in the field of respiratory infection, and in some cases is beginning to act as a viable alternative to traditional culture. NGS has revolutionized our understanding of airway microbiota and in particular fungi. In this context, it permits the identification of the previously unculturable, fungal composition, and dynamic change within microbial communities of the airway, including potential roles in chronic respiratory disease. Furthermore, inter-kingdom microbial interactions, including fungi, in conjunction with host immunity have recently been shown to have important clinical roles in COPD and bronchiectasis. In this review, we provide an overview of clinical Aspergillus signatures in COPD and bronchiectasis and cover the current advances in the understanding of the mycobiome in these disease states. The challenges and limitations of NGS will be addressed.
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Affiliation(s)
- Pei Yee Tiew
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore 168753, Singapore;
- Duke-NUS Medical School, Singapore 169857, Singapore
| | - Kai Xian Thng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore;
| | - Sanjay H. Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore;
- Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore 308433, Singapore
- Correspondence:
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Tiew PY, Hou Lim AY, Keir HR, Dicker AJ, Aogáin MM, Pang SL, Boon LT, Hassan TM, Poh ME, Xu H, Ong TH, Koh MS, Abisheganaden JA, Tee A, Chew FT, Chalmers JD, Chotirmall SH. HIGH FREQUENCY OF ALLERGIC BRONCHOPULMONARY ASPERGILLOSIS IN BRONCHIECTASIS-COPD OVERLAP. Chest 2021; 161:40-53. [PMID: 34364870 DOI: 10.1016/j.chest.2021.07.2165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/22/2021] [Accepted: 07/25/2021] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Allergic bronchopulmonary aspergillosis (ABPA) is associated with frequent exacerbations and poor outcomes in chronic respiratory disease but remains underdiagnosed. The role of fungal sensitization in bronchiectasis-COPD overlap (BCO) is unknown. RESEARCH QUESTION What is the occurrence and clinical relevance of Aspergillus sensitization and ABPA in BCO when compared to individuals with COPD or bronchiectasis without overlap? STUDY DESIGN Prospective, observational and cross-sectional. METHODS We prospectively recruited n=280 patients during periods of clinical stability with bronchiectasis (n=183), COPD (n=50) and BCO (n=47) from six hospitals across three countries (Singapore, Malaysia, and Scotland). We assessed sensitization responses (as specific IgE) to a panel of recombinant Aspergillus fumigatus (rAsp f) allergens and the occurrence of ABPA (ABPA) in relation to clinical outcomes. RESULTS Individuals with BCO illustrate an increased frequency and clinical severity of ABPA compared to COPD and bronchiectasis without overlap. BCO-associated ABPA demonstrates more severe disease, higher exacerbation rates and lower lung function when compared to ABPA occurring in the absence of overlap. BCO with a severe bronchiectasis severity index (BSI) (>9) significantly associates with the occurrence of ABPA that is unrelated to underlying COPD severity. CONCLUSIONS BCO demonstrates a high frequency of ABPA that associates with a severe BSI (>9) and poor clinical outcomes. Clinicians should maintain a high index of suspicion for the potential development of ABPA in BCO patients with high BSI.
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Affiliation(s)
- Pei Yee Tiew
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore
| | - Albert Yick Hou Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore
| | - Holly R Keir
- Ninewells Hospital and Medical School, University of Dundee, UK
| | - Alison J Dicker
- Ninewells Hospital and Medical School, University of Dundee, UK
| | - Micheál Mac Aogáin
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Sze Lei Pang
- Department of Biological Sciences, National University of Singapore
| | - Low Teck Boon
- Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore
| | | | - Mau Ern Poh
- Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Huiying Xu
- Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore
| | - Thun How Ong
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore
| | - Mariko Siyue Koh
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore
| | - John Arputhan Abisheganaden
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore; Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore
| | - Augustine Tee
- Department of Respiratory and Critical Care Medicine, Changi General Hospital, Singapore
| | - Fook Tim Chew
- Department of Biological Sciences, National University of Singapore
| | | | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
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Abstract
Bronchiectasis is a complex, heterogeneous disorder defined by both a radiological abnormality of permanent bronchial dilatation and a clinical syndrome. There are multiple underlying causes including severe infections, mycobacterial disease, autoimmune conditions, hypersensitivity disorders, and genetic conditions. The pathophysiology of disease is understood in terms of interdependent concepts of chronic infection, inflammation, impaired mucociliary clearance, and structural lung damage. Neutrophilic inflammation is characteristic of the disease, with elevated levels of harmful proteases such as neutrophil elastase associated with worse outcomes. Recent data show that neutrophil extracellular trap formation may be the key mechanism leading to protease release and severe bronchiectasis. Despite the dominant of neutrophilic disease, eosinophilic subtypes are recognized and may require specific treatments. Neutrophilic inflammation is associated with elevated bacterial loads and chronic infection with organisms such as Pseudomonas aeruginosa. Loss of diversity of the normal lung microbiota and dominance of proteobacteria such as Pseudomonas and Haemophilus are features of severe bronchiectasis and link to poor outcomes. Ciliary dysfunction is also a key feature, exemplified by the rare genetic syndrome of primary ciliary dyskinesia. Mucus symptoms arise through goblet cell hyperplasia and metaplasia and reduced ciliary function through dyskinesia and loss of ciliated cells. The contribution of chronic inflammation, infection, and mucus obstruction leads to progressive structural lung damage. The heterogeneity of the disease is the most challenging aspect of management. An understanding of the pathophysiology of disease and their biomarkers can help to guide personalized medicine approaches utilizing the concept of "treatable traits."
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Affiliation(s)
- Holly R Keir
- Scottish Centre for Respiratory Research, University of Dundee, Dundee, United Kingdom
| | - James D Chalmers
- Scottish Centre for Respiratory Research, University of Dundee, Dundee, United Kingdom
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Jaggi TK, Ter SK, Mac Aogáin M, Chotirmall SH. Aspergillus-Associated Endophenotypes in Bronchiectasis. Semin Respir Crit Care Med 2021; 42:556-566. [PMID: 34261180 DOI: 10.1055/s-0041-1730947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Bronchiectasis is a chronic condition of global relevance resulting in permanent and irreversible structural airway damage. Bacterial infection in bronchiectasis is well studied; however, recent molecular studies identify fungi as important pathogens, either independently or in association with bacteria. Aspergillus species are established fungal pathogens in cystic fibrosis and their role is now increasingly being recognized in noncystic fibrosis bronchiectasis. While the healthy airway is constantly exposed to ubiquitously present Aspergillus conidia in the environment, anatomically damaged airways appear more prone to colonization and subsequent infection by this fungal group. Aspergilli possess diverse immunopathological mechanistic capabilities and when coupled with innate immune defects in a susceptible host, such as that observed in bronchiectasis, it may promote a range of clinical manifestations including sensitization, allergic bronchopulmonary aspergillosis, Aspergillus bronchitis, and/or invasive aspergillosis. How such clinical states influence "endophenotypes" in bronchiectasis is therefore of importance, as each Aspergillus-associated disease state has overlapping features with bronchiectasis itself, and can evolve, depending on underlying host immunity from one type into another. Concurrent Aspergillus infection complicates the clinical course and exacerbations in bronchiectasis and therefore dedicated research to better understand the Aspergillus-host interaction in the bronchiectasis airway is now warranted.
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Affiliation(s)
- Tavleen Kaur Jaggi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Soo Kai Ter
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Micheál Mac Aogáin
- Biochemical Genetics Laboratory, Department of Biochemistry, St. James's Hospital, Dublin, Ireland.,Clinical Biochemistry Unit, School of Medicine, Trinity College Dublin, Ireland
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Respiratory Mycoses in COPD and Bronchiectasis. Mycopathologia 2021; 186:623-638. [PMID: 33709335 DOI: 10.1007/s11046-021-00539-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/22/2021] [Indexed: 02/07/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) and bronchiectasis represent chronic airway diseases associated with significant morbidity and mortality. Bacteria and viruses are commonly implicated in acute exacerbations; however the significance of fungi in these airways remains poorly defined. While COPD and bronchiectasis remain recognized risk factors for the occurrence of Aspergillus-associated disease including chronic and invasive aspergillosis, underlying mechanisms that lead to the progression from colonization to invasive disease remain uncertain. Nonetheless, advances in molecular technologies have improved our detection, identification and understanding of resident fungi characterizing these airways. Mycobiome sequencing has revealed the complex varied and myriad profile of airway fungi in COPD and bronchiectasis, including their association with disease presentation, progression, and mortality. In this review, we outline the emerging evidence for the clinical importance of fungi in COPD and bronchiectasis, available diagnostic modalities, mycobiome sequencing approaches and association with clinical outcomes.
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Ali NABM, Ivan FX, Mac Aogáin M, Narayana JK, Lee SY, Lim CL, Chotirmall SH. The Healthy Airway Mycobiome in Individuals of Asian Descent. Chest 2020; 159:544-548. [PMID: 32926873 DOI: 10.1016/j.chest.2020.09.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 08/27/2020] [Accepted: 09/02/2020] [Indexed: 01/07/2023] Open
Affiliation(s)
| | | | - Micheál Mac Aogáin
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | | | - Shuen Yee Lee
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Chin Leong Lim
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
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Cai G, Bossé Y, Xiao F, Kheradmand F, Amos CI. Reply to Polverino: Cigarette Smoking and COVID-19: A Complex Interaction. Am J Respir Crit Care Med 2020; 202:472-474. [PMID: 32530707 PMCID: PMC7397808 DOI: 10.1164/rccm.202005-1807le] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Guoshuai Cai
- University of South CarolinaColumbia, South Carolina
| | | | - Feifei Xiao
- University of South CarolinaColumbia, South Carolina
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Poh TY, Ali NABM, Chan LL, Tiew PY, Chotirmall SH. Evaluation of Droplet Digital Polymerase Chain Reaction (ddPCR) for the Absolute Quantification of Aspergillus species in the Human Airway. Int J Mol Sci 2020; 21:E3043. [PMID: 32357408 PMCID: PMC7247686 DOI: 10.3390/ijms21093043] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Prior studies illustrate the presence and clinical importance of detecting Aspergillus species in the airways of patients with chronic respiratory disease. Despite this, a low fungal biomass and the presence of PCR inhibitors limits the usefulness of quantitative PCR (qPCR) for accurate absolute quantification of Aspergillus in specimens from the human airway. Droplet digital PCR (ddPCR) however, presents an alternative methodology allowing higher sensitivity and accuracy of such quantification but remains to be evaluated in head-to-head fashion using specimens from the human airway. Here, we implement a standard duplex TaqMan PCR protocol, and assess if ddPCR is superior in quantifying airway Aspergillus when compared to standard qPCR. METHODS The molecular approaches of qPCR and ddPCR were applied to DNA fungal extracts in n = 20 sputum specimens obtained from non-diseased (n = 4), chronic obstructive pulmonary disease (COPD; n = 8) and non-cystic fibrosis bronchiectasis (n = 8) patients where Aspergillus status was known. DNA was extracted and qPCR and ddPCR performed on all specimens with appropriate controls and head-to-head comparisons performed. RESULTS Standard qPCR and ddPCR were both able to detect, even at low abundance, Aspergillus species (Aspergillus fumigatus - A. fumigatus and Aspergillus terreus - A. terreus) from specimens known to contain the respective fungi. Importantly, however, ddPCR was superior for the detection of A. terreus particularly when present at very low abundance and demonstrates greater resistance to PCR inhibition compared to qPCR. CONCLUSION ddPCR has greater sensitivity for A. terreus detection from respiratory specimens, and is more resistant to PCR inhibition, important attributes considering the importance of A. terreus species in chronic respiratory disease states such as bronchiectasis.
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Affiliation(s)
- Tuang Yeow Poh
- Translational Respiratory Research Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
| | - Nur A’tikah Binte Mohamed Ali
- Translational Respiratory Research Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
| | - Louisa L.Y. Chan
- Translational Respiratory Research Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
| | - Pei Yee Tiew
- Translational Respiratory Research Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore 169608, Singapore
| | - Sanjay H. Chotirmall
- Translational Respiratory Research Laboratory, Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore 308232, Singapore
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