Autoantibody profile in eosinophilic granulomatosis and polyangiitis: predominance of anti-alpha-enolase antibodies
K. Laskari1, B. Hellmich2, G. Adamus3, E. Csernok4
- Rheumatology Unit, 1st Department of Propaedeutic Internal Medicine, Joint Academic Rheumatology Program, Medical School, University of Athens, Greece.
- Department of Internal Medicine, Rheumatology and Immunology, Vasculitis-Centre Tübingen-Kirchheim, Medius Klinik Kirchheim, University of Tübingen, Kirchheim-Teck, Germany.
- Ocular Immunology Laboratory, Casey Eye Institute, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
- Department of Internal Medicine, Rheumatology and Immunology, Vasculitis-Centre Tübingen-Kirchheim, Medius Klinik Kirchheim, University of Tübingen, Kirchheim-Teck, Germany. email@example.com
2021 Vol.39, N°2 ,Suppl.129
PI 0083, PF 0087
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PMID: 33200729 [PubMed]
Accepted : 31/08/2020
In Press: 05/11/2020
To evaluate the autoantibody profile in eosinophilic granulomatosis and polyangiitis (EGPA) patients.
33 EGPA patients were tested for anti-neutrophil cytoplasmic antibodies (ANCA), antinuclear antibodies (ANA), rheumatoid factor (RF), anti-alpha-enolase antibodies, and anti-eosinophil peroxidase (EPO) antibodies. Granulomatosis with polyangiitis (GPA), microscopic polyangiitis (MPA), hypereosinophilic syndrome (HES), rheumatoid arthritis (RA), primary biliary cirrhosis (PBC) patients and healthy subjects were tested as a control group.
Anti-alpha-enolase antibodies were positive in 82% of EGPA patients at high titers. Although a high sensitivity was shown for an anti-alpha-enolase antibody titer above 1/100 (82%), the specificity for EGPA remained low (44%) (AUC=0.653, p=0.008). Anti-alpha-enolase antibodies predominated in males with EGPA (p=0.048) and were associated with skin involvement (p=0.040). Most of the EGPA patients positive for anti-alpha enolase antibodies (20 out of 27) had a negative indirect immunofluorescence test (IFT) for ANCA. ANCA were positive in 8 EGPA patients (24%) with a perinuclear pattern in all but one patient. The ANCA-target antigen was myeloperoxidase (MPO) and/or alpha-enolase. A usually fine-speckled ANA pattern was observed in 42% of the EGPA patients. RF was positive in 1 (6%) of the 18 EGPA patients tested. There was no association between the presence and levels of autoantibodies and EGPA disease activity. None of the patients and controls was positive for anti-EPO antibodies.
Alpha-enolase may be a target of autoimmunity in EGPA patients and shows usually negative ANCA IFT results.