Identification of autoantigens and their potential post-translational modification in EGPA and severe eosinophilic asthma

Frontiers in Immunology

Immunology

Michael Stevens¹  Galateia Verykokou²  James Brown³  Richard Stratton⁴  Roberto Buccafusca⁵  Ilaria Esposito⁶  Ahuva Nissim⁶  Ioanna Kontra⁶  Myles J. Lewis⁶  Sotiria Manou-Stathopoulou⁶  Paul E. Pfeffer⁷  Chiara Giacomassi⁸ 

[1]Department of Clinical Immunology, Barts Health NHS Trust, London, United Kingdom

[2]Department of Clinical Immunology, University Hospitals Sussex NHS Foundation Trust, Brighton, United Kingdom

[3]Department of Respiratory Medicine, Barts Health NHS Trust, London, United Kingdom

[4]Department of Respiratory Medicine, Royal Free NHS Foundation Trust, London, United Kingdom

[5]Department of Rheumatology, Royal Free NHS Foundation Trust, London, United Kingdom

[6]Centre for Rheumatology, University College London, London, United Kingdom

[7]School of Physical and Chemical Sciences, Queen Mary University of London, London, United Kingdom

[8]William Harvey Research Institute, Queen Mary University of London, London, United Kingdom

[9]William Harvey Research Institute, Queen Mary University of London, London, United Kingdom

[10]Department of Respiratory Medicine, Barts Health NHS Trust, London, United Kingdom

[11]William Harvey Research Institute, Queen Mary University of London, London, United Kingdom

[12]Department of Rheumatology, Royal Free NHS Foundation Trust, London, United Kingdom

关键词: eosinophil;    autoantibodies;    autoantigens;    oxidative modification;    diagnostic test;    TREM1;    eosinophil peroxidase;    NETosis;   

DOI  :  10.3389/fimmu.2023.1164941

 received in 2023-02-13, accepted in 2023-05-18,  发布年份 2023

来源: Frontiers

【 摘 要 】

BackgroundThe chronic airway inflammation in severe eosinophilic asthma (SEA) suggests potential autoimmune aetiology with unidentified autoantibodies analogous to myeloperoxidase (MPO) in ANCA-positive EGPA (eosinophilic granulomatosis with polyangiitis). Previous research has shown that oxidative post-translational modification (oxPTM) of proteins is an important mechanism by which autoantibody responses may escape immune tolerance. Autoantibodies to oxPTM autoantigens in SEA have not previously been studied.MethodsPatients with EGPA and SEA were recruited as well as healthy control participants. Autoantigen agnostic approach: Participant serum was incubated with slides of unstimulated and PMA-stimulated neutrophils and eosinophils, and autoantibodies to granulocytes were identified by immunofluorescence with anti-human IgG FITC antibody. Target autoantigen approach: Candidate proteins were identified from previous literature and FANTOM5 gene set analysis for eosinophil expressed proteins. Serum IgG autoantibodies to these proteins, in native and oxPTM form, were detected by indirect ELISA.ResultsImmunofluorescence studies showed that serum from patients with known ANCA stained for IgG against neutrophils as expected. In addition, serum from 9 of 17 tested SEA patients stained for IgG to PMA-stimulated neutrophils undergoing NETosis. Immunofluorescent staining of eosinophil slides was evident with serum from all participants (healthy and with eosinophilic disease) with diffuse cytoplasmic staining except for one SEA individual in whom subtle nuclear staining was evident. FANTOM5 gene set analysis identified TREM1 (triggering receptor expressed on myeloid cells 1) and IL-1 receptor 2 (IL1R2) as eosinophil-specific targets to test for autoantibody responses in addition to MPO, eosinophil peroxidase (EPX), and Collagen-V identified from previous literature. Indirect ELISAs found high concentrations of serum autoantibodies to Collagen-V, MPO, and TREM1 in a higher proportion of SEA patients than healthy controls. High concentrations of serum autoantibodies to EPX were evident in serum from both healthy and SEA participants. The proportion of patients with positive autoantibody ELISAs was not increased when examining oxPTM compared to native proteins.DiscussionAlthough none of the target proteins studied showed high sensitivity for SEA, the high proportion of patients positive for at least one serum autoantibody shows the potential of more research on autoantibody serology to improve diagnostic testing for severe asthma.Clinical trial registrationClinicalTrials.gov, identifier, NCT04671446.

【 授权许可】

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Copyright © 2023 Esposito, Kontra, Giacomassi, Manou-Stathopoulou, Brown, Stratton, Verykokou, Buccafusca, Stevens, Nissim, Lewis and Pfeffer