Autoantibodies are present in the bronchoalveolar lavage but not circulation in patients with fibrotic interstitial lung disease

Karim Boustani, Poonam Ghai, Rachele Invernizzi, Richard J. Hewitt, Toby M. Maher, Quan Zhen Li, Philip L. Molyneaux, James A. Harker

Research output: Contribution to journalArticlepeer-review

Abstract

Background Fibrotic interstitial lung disease (fILD) has previously been associated with the presence of autoantibody. While studies have focused on systemic autoimmunity, the role of local autoantibodies in the airways remains unknown. We therefore extensively characterised the airway and peripheral autoantibody profiles in patients with fILD, and assessed association with disease severity and outcome. Methods Bronchoalveolar lavage (BAL) fluid was collected from a cohort of fILD patients and total BAL antibody concentrations were quantified. An autoantigen microarray was used to measure IgG and IgA autoantibodies against 122 autoantigens in BAL from 40 idiopathic pulmonary fibrosis (IPF), 20 chronic hypersensitivity pneumonitis (CHP), 20 connective tissue disease-associated ILD (CTD-ILD) patients and 20 controls. Results A subset of patients with fILD but not healthy controls had a local autoimmune signature in their BAL that was not present systemically, regardless of disease. The proportion of patients with IPF with a local autoantibody signature was comparable to that of CTD-ILD, which has a known autoimmune pathology, identifying a potentially novel subset of patients. The presence of an airway autoimmune signature was not associated with reduced survival probability or changes in lung function in the cohort as a whole. Patients with IPF had increased BAL total IgA and IgG1 while subjects with CHP had increased BAL IgA, IgG1 and IgG4. In patients with CHP, increased BAL total IgA was associated with reduced survival probability. Conclusion Airway autoantibodies that are not present systemically identify a group of patients with fILD and the mechanisms by which these autoantibodies contribute to disease requires further investigation.

Original languageEnglish (US)
Article number00481-2021
JournalERJ Open Research
Volume8
Issue number1
DOIs
StatePublished - Jan 2022
Externally publishedYes

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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