Document Detail

Impaired macrophage phagocytosis in non-eosinophilic asthma.
MedLine Citation:
PMID:  23278878     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Many patients with non-eosinophilic asthma have increased numbers of neutrophils in the airways. The explanation for this chronic inflammation remains unclear, but may result from an impaired ability of alveolar macrophages to phagocytose apoptotic cells (a process termed 'efferocytosis'), as we have shown in chronic obstructive pulmonary disease (COPD).
OBJECTIVES: To examine induced sputum as a non-invasive technique to characterize efferocytosis in chronic lung diseases and to compare efferocytosis in patients with non-eosinophilic asthma, eosinophilic asthma and COPD.
METHODS: Participants with stable asthma (20 with eosinophilic and 30 with non-eosinophilic) and COPD (n = 11) underwent clinical assessment including allergy skin tests, saline challenge and sputum induction. Sputum cells were dispersed using dithiothreitol and resuspended in culture medium. Efferocytosis of apoptotic bronchial epithelial cells by sputum-derived macrophages was determined using flow cytometry.
RESULTS: There were no significant differences in efferocytosis between paired sputum and bronchoalveolar lavage macrophages from three subjects. Efferocytosis was significantly impaired in patients with non-eosinophilic asthma [mean (SD) 0.95 (0.24)] compared with eosinophilic asthma [1.17 (0.19)] and to a similar degree as patients with COPD [1.04 (0.16)]. Sputum neutrophils were significantly higher in patients with COPD and non-eosinophilic asthma compared with eosinophilic asthma.
CONCLUSION AND CLINICAL RELEVANCE: Induced sputum provides a reliable and non-invasive method for studying macrophage efferocytosis in chronic lung disease. Macrophage efferocytosis is impaired in non-eosinophilic asthma to a similar degree as that in COPD and may explain the persistent airway neutrophilia and chronic inflammation that characterizes this asthma subtype.
J L Simpson; P G Gibson; I A Yang; J Upham; A James; P N Reynolds; S Hodge;
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology     Volume:  43     ISSN:  1365-2222     ISO Abbreviation:  Clin. Exp. Allergy     Publication Date:  2013 Jan 
Date Detail:
Created Date:  2013-01-02     Completed Date:  2013-07-25     Revised Date:  2013-10-07    
Medline Journal Info:
Nlm Unique ID:  8906443     Medline TA:  Clin Exp Allergy     Country:  England    
Other Details:
Languages:  eng     Pagination:  29-35     Citation Subset:  IM    
Copyright Information:
© 2012 Blackwell Publishing Ltd.
Centre for Asthma and Respiratory Disease, The University of Newcastle, Newcastle, Australia.
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MeSH Terms
Asthma / immunology*,  pathology
Bronchoalveolar Lavage Fluid / cytology,  immunology
Flow Cytometry
Macrophages, Alveolar / immunology*,  pathology
Middle Aged
Phagocytosis / immunology*
Pulmonary Disease, Chronic Obstructive / immunology,  pathology
Pulmonary Eosinophilia / immunology,  pathology
Sputum / cytology,  immunology
Comment In:
Clin Exp Allergy. 2013 Sep;43(9):1083-5   [PMID:  23957344 ]
Clin Exp Allergy. 2013 Sep;43(9):1086-8   [PMID:  23957345 ]

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