Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Jun 21:2:676930.
doi: 10.3389/falgy.2021.676930. eCollection 2021.

Neutrophilic Asthma Is Associated With Smoking, High Numbers of IRF5+, and Low Numbers of IL10+ Macrophages

Affiliations

Neutrophilic Asthma Is Associated With Smoking, High Numbers of IRF5+, and Low Numbers of IL10+ Macrophages

Nil Turan et al. Front Allergy. .

Abstract

Asthma is a heterogenous disease with different inflammatory subgroups that differ in disease severity. This disease variation is hampering treatment and development of new treatment strategies. Macrophages may contribute to asthma phenotypes by their ability to activate in different ways, i.e., T helper cell 1 (Th1)-associated, Th2-associated, or anti-inflammatory activation. It is currently unknown if these different types of activation correspond with specific inflammatory subgroups of asthma. We hypothesized that eosinophilic asthma would be characterized by having Th2-associated macrophages, whereas neutrophilic asthma would have Th1-associated macrophages and both having few anti-inflammatory macrophages. We quantified macrophage subsets in bronchial biopsies of asthma patients using interferon regulatory factor 5 (IRF5)/CD68 for Th1-associated macrophages, CD206/CD68 for Th2-associated macrophages and interleukin 10 (IL10)/CD68 for anti-inflammatory macrophages. Macrophage subset percentages were investigated in subgroups of asthma as defined by unsupervised clustering using neutrophil/eosinophil counts in sputum and tissue and forced expiratory volume in 1 s (FEV1). Asthma patients clustered into four subgroups: mixed-eosinophilic/neutrophilic, paucigranulocytic, neutrophilic with normal FEV1, and neutrophilic with low FEV1, the latter group consisting mainly of smokers. No differences were found for CD206+ macrophages within asthma subgroups. In contrast, IRF5+ macrophages were significantly higher and IL10+ macrophages lower in neutrophilic asthmatics with low FEV1 as compared to those with neutrophilic asthma and normal FEV1 or mixed-eosinophilic asthma. This study shows that neutrophilic asthma with low FEV1 is associated with high numbers of IRF5+, and low numbers of IL10+ macrophages, which may be the result of combined effects of smoking and having asthma.

Keywords: CD206; FEV1; M1; M2; biopsy; inflammatory endotypes; macrophages subtypes.

PubMed Disclaimer

Conflict of interest statement

AO and NT were employed by the company GlaxoSmithKline at the time of data analysis and manuscript writing. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
The clustering analysis based on neutrophil and eosinophil counts and lung function resulted in five groups of patients of which four had phenotypically different disease: patients with asthma characterized by mixed eosinophilic/neutrophilic inflammation (Eos/Mix), with neutrophilic asthma with low FEV1 (Neutro Low FEV), with neutrophilic asthma with normal FEV1 (Neutro Normal FEV), or with paucigranulocytic asthma (Pauci).
Figure 2
Figure 2
(A) The percentage of CD206+ macrophages present in bronchial biopsies of patients from the four subclusters and healthy controls. (B) The percentage of IRF5+ macrophages present in bronchial biopsies of patients from the four subclusters. (C) The percentage of IL10+ macrophages present in bronchial biopsies of patients from the four subclusters and healthy controls. *Healthy controls were added for comparison and are significantly different (p = 1.9E-17 for IRF5+, p = 3.9E-17 for CD206+, and p = 3.1E-15 for IL10+ macrophages respectively) from individuals with asthma as we have reported before (6). The asthma subgroups were compared using one-way ANOVA with post-hoc testing to compare groups, p-values < 0.05 were considered significant. ICS, inhaled corticosteroids.

Similar articles

Cited by

References

    1. Fitzpatrick A, Moore W. Severe Asthma Phenotypes - How Should They Guide Evaluation and Treatment. J Allergy Clin Immunol Pract. (2017) 5:901–8. 10.1016/j.jaip.2017.05.015 - DOI - PMC - PubMed
    1. Shaw D, Sousa A, Fowler S, Fleming L, Roberts G, Corfield J, et al. . Clinical and inflammatory characteristics of the European U-BIOPRED adult severe asthma cohort. Eur Respir J. (2015) 46:1308–21. 10.1183/13993003.00779-2015 - DOI - PubMed
    1. Lötvall J, Akdis C, Bacharier L, Bjermer L, Casale T, Custovic A, et al. . Asthma endotypes: a new approach to classification of disease entities within the asthma syndrome. J Allergy Clin Immunol. (2011) 127:355–60. 10.1016/j.jaci.2010.11.037 - DOI - PubMed
    1. Tang HHF, Sly PD, Holt PG, Holt KE, Inouye M. Systems biology and big data in asthma and allergy: recent discoveries and emerging challenges. Eur Respir J. (2020) 55:1900844. 10.1183/13993003.00844-2019 - DOI - PubMed
    1. Draijer C, Robbe P, Boorsma CE, Hylkema MN, Melgert BN. Dual role of YM1+ M2 macrophages in allergic lung inflammation. Sci Rep. (2018) 8:5105. 10.1038/s41598-018-23269-7 - DOI - PMC - PubMed

LinkOut - more resources