TY - JOUR T1 - Autoantibodies are present in the bronchoalveolar lavage but not circulation in patients with fibrotic interstitial lung disease JF - ERJ Open Research JO - erjor DO - 10.1183/23120541.00481-2021 SP - 00481-2021 AU - Karim Boustani AU - Poonam Ghai AU - Rachele Invernizzi AU - Richard J. Hewitt AU - Toby M. Maher AU - Quan-Zhen Li AU - Philip L. Molyneaux AU - James A. Harker Y1 - 2021/01/01 UR - http://openres.ersjournals.com/content/early/2021/10/28/23120541.00481-2021.abstract N2 - 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) 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 aren't present systemically identify a group of patients with fILD and the mechanisms by which these autoantibodies contribute to disease requires further investigation.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Karim Boustani has nothing to disclose.Conflict of interest: Poonam Ghai has nothing to disclose.Conflict of interest: Rachele Invernizzi has nothing to disclose.Conflict of interest: Richard J. Hewitt has nothing to disclose.Conflict of interest: Toby Maher reports grants and personal fees from GSK, personal fees from Boehringer Ingelheim, grants and personal fees from Astra Zeneca, personal fees from Roche, personal fees from Galapagos, personal fees from Celgene, personal fees from Pliant, personal fees from Blade Therapeutics, personal fees from Respivant, personal fees from Bristol-Myers Squibb, personal fees from Galecto, personal fees from Theravance, personal fees from IQVIA, personal fees from Veracyte, outside the submitted work.Conflict of interest: Quan-Zhen Li has nothing to disclose.Conflict of interest: Philip Molyneaux reports receiving grant funding to institution from AstraZeneca, outside the submitted work. Consulting speaker fees from Boehringer Ingelheim and Hoffman-La Roche, outside the submitted work.Conflict of interest: James A. Harker has nothing to disclose. ER -