Eosinophilic airway inflammation in asthmatic patients is associated with an altered airway microbiome

TY - JOUR

T1 - Eosinophilic airway inflammation in asthmatic patients is associated with an altered airway microbiome

AU - Sverrild, Asger

AU - Kiilerich, Pia

AU - Brejnrod, Asker Daniel

AU - Pedersen, Rebecca

AU - Porsbjerg, Celeste

AU - Bergqvist, Anders

AU - Erjefält, Jonas S.

AU - Kristiansen, Karsten

AU - Backer, Vibeke

N1 - Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

PY - 2017/8

Y1 - 2017/8

N2 - BACKGROUND: Asthmatic patients have higher microbiome diversity and an altered composition, with more Proteobacteria and less Bacteroidetes compared with healthy control subjects. Studies comparing airway inflammation and the airway microbiome are sparse, especially in subjects not receiving anti-inflammatory treatment.OBJECTIVE: We sought to describe the relationship between the airway microbiome and patterns of airway inflammation in steroid-free patients with asthma and healthy control subjects.METHODS: Bronchoalveolar lavage fluid was collected from 23 steroid-free nonsmoking patients with asthma and 10 healthy control subjects. Bacterial DNA was extracted from and subjected to Illumina MiSeq sequencing of the 16S rDNA V4 region. Eosinophils and neutrophils in the submucosa were quantified by means of immunohistochemical identification and computerized image analysis. Induced sputum was obtained, and airway hyperresponsiveness to mannitol and fraction of exhaled nitric oxide values were measured. Relationships between airway microbial diversity and composition and inflammatory profiles were analyzed.RESULTS: In asthmatic patients airway microbial composition was associated with airway eosinophilia and AHR to mannitol but not airway neutrophilia. The overall composition of the airway microbiome of asthmatic patients with the lowest levels of eosinophils but not asthmatic patients with the highest levels of eosinophils deviated significantly from that of healthy subjects. Asthmatic patients with the lowest levels of eosinophils had an altered bacterial abundance profile, with more Neisseria, Bacteroides, and Rothia species and less Sphingomonas, Halomonas, and Aeribacillus species compared with asthmatic patients with more eosinophils and healthy control subjects.CONCLUSION: The level of eosinophilic airway inflammation correlates with variations in the microbiome across asthmatic patients, whereas neutrophilic airway inflammation does not. This warrants further investigation on molecular pathways involved in both patients with eosinophilic and those with noneosinophilic asthma.

AB - BACKGROUND: Asthmatic patients have higher microbiome diversity and an altered composition, with more Proteobacteria and less Bacteroidetes compared with healthy control subjects. Studies comparing airway inflammation and the airway microbiome are sparse, especially in subjects not receiving anti-inflammatory treatment.OBJECTIVE: We sought to describe the relationship between the airway microbiome and patterns of airway inflammation in steroid-free patients with asthma and healthy control subjects.METHODS: Bronchoalveolar lavage fluid was collected from 23 steroid-free nonsmoking patients with asthma and 10 healthy control subjects. Bacterial DNA was extracted from and subjected to Illumina MiSeq sequencing of the 16S rDNA V4 region. Eosinophils and neutrophils in the submucosa were quantified by means of immunohistochemical identification and computerized image analysis. Induced sputum was obtained, and airway hyperresponsiveness to mannitol and fraction of exhaled nitric oxide values were measured. Relationships between airway microbial diversity and composition and inflammatory profiles were analyzed.RESULTS: In asthmatic patients airway microbial composition was associated with airway eosinophilia and AHR to mannitol but not airway neutrophilia. The overall composition of the airway microbiome of asthmatic patients with the lowest levels of eosinophils but not asthmatic patients with the highest levels of eosinophils deviated significantly from that of healthy subjects. Asthmatic patients with the lowest levels of eosinophils had an altered bacterial abundance profile, with more Neisseria, Bacteroides, and Rothia species and less Sphingomonas, Halomonas, and Aeribacillus species compared with asthmatic patients with more eosinophils and healthy control subjects.CONCLUSION: The level of eosinophilic airway inflammation correlates with variations in the microbiome across asthmatic patients, whereas neutrophilic airway inflammation does not. This warrants further investigation on molecular pathways involved in both patients with eosinophilic and those with noneosinophilic asthma.

KW - Journal Article

U2 - 10.1016/j.jaci.2016.10.046

DO - 10.1016/j.jaci.2016.10.046

M3 - Journal article

C2 - 28042058

SN - 0091-6749

VL - 140

SP - 407

EP - 417

JO - Journal of Allergy and Clinical Immunology

JF - Journal of Allergy and Clinical Immunology

IS - 2

M1 - e11

ER -