Microbial ligand costimulation drives neutrophilic steroid-refractory asthma

Hadebe, Sabelo; Kirstein, Frank; Fierens, Kaat; Chen, Kong; Drummond, Rebecca A; Vautier, Simon; Sajaniemi, Sara; Murray, Graeme; Williams, David L; Redelinghuys, Pierre; Reinhart, Todd A; Junecko, Beth A Fallert; Kolls, Jay K; Lambrecht, Bart N; Brombacher, Frank; Brown, Gordon D

Microbial ligand costimulation drives neutrophilic steroid-refractory asthma

Journal Article

2015

Journal Title

PLoS One

Link to Journal

http://journals.plos.org/plosone

Publisher

Public Library of Science

Publisher

University of Cape Town

Department

Institute of Infectious Disease and Molecular Medicine

Faculty

Faculty of Health Sciences

License

http://creativecommons.org/licenses/by/4.0

Abstract

Asthma is a heterogeneous disease whose etiology is poorly understood but is likely to involve innate responses to inhaled microbial components that are found in allergens. The influence of these components on pulmonary inflammation has been largely studied in the context of individual agonists, despite knowledge that they can have synergistic effects when used in combination. Here we have explored the effects of LPS and β-glucan, two commonly-encountered microbial agonists, on the pathogenesis of allergic and non-allergic respiratory responses to house dust mite allergen. Notably, sensitization with these microbial components in combination acted synergistically to promote robust neutrophilic inflammation, which involved both Dectin-1 and TLR-4. This pulmonary neutrophilic inflammation was corticosteroid-refractory, resembling that found in patients with severe asthma. Thus our results provide key new insights into how microbial components influence the development of respiratory pathology.