Diagnosis of myositis-associated interstitial lung disease: Utility of the myositis autoantibody line immunoassay.

Aug 30, 2021

Contributor: Adelle S Jee,Matthew J S Parker,Jane F Bleasel,Lauren K Troy,Edmund M Lau,Helen E Jo,Alan K Y Teoh,Susanne Webster,Stephen Adelstein,Tamera J Corte

Diagnosis of myositis-associated interstitial lung disease: Utility of the myositis autoantibody line immunoassay.

The detection of myositis autoantibodies (MA) in patients with interstitial lung disease (ILD) has major implications for diagnosis and management, especially amyopathic and forme frustes of idiopathic inflammatory myositis-associated ILD (IIM-ILD). Use of the MA line immunoblot assay (MA-LIA) in non-rheumatological cohorts remains unvalidated. We assessed the diagnostic performance of the MA-LIA and explored combined models with clinical variables to improve identification of patients with IIM-ILD.
Consecutive patients referred to a specialist ILD clinic, with ILD-diagnosis confirmed at multidisciplinary meeting, and MA-LIA performed within six months of baseline were included. Pre-specified MA-LIA thresholds were evaluated for IIM-ILD diagnosis.
A total 247 ILD patients were included (IIM-ILD n = 12, non-IIM connective tissue disease-associated ILD [CTD-ILD] n = 52, idiopathic interstitial pneumonia [IIP] n = 115, other-ILD n = 68). Mean age was 64.8 years, with 45.3% female, mean FVC 75.5% and DLCO 59.2% predicted. MA were present in 13.8% overall and 83.3% of IIM-ILD patients. The most common MA in IIM-ILD and non-IIM ILD patients were anti-Jo-1 (prevalence 40%) and anti-PMScl (29.2%) autoantibodies respectively. The pre-specified low-positive threshold (>10 signal intensity) had the highest discriminative capacity for IIM-ILD (AUC 0.86). Combining MA-LIA with age, gender, clinical CTD-manifestations and an overlap non-specific interstitial pneumonia/organising pneumonia pattern on HRCT improved discrimination for IIM-ILD (AUC 0.96).
The MA-LIA is useful to support a diagnosis of IIM-ILD as a complement to multi-disciplinary ILD assessment. Clinical interpretation is optimised by consideration of the strength of the MA-LIA result together with clinical and radiological features of IIM-ILD.

Copyright © 2021 Elsevier Ltd. All rights reserved.

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About The Expert

Adelle S Jee

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; National Health and Medical Research Council (NHMRC) Centre of Research Excellence in Pulmonary Fibrosis, Australia. Electronic address: adelle.jee@health.nsw.gov.au.

Matthew J S Parker

Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; National Health and Medical Research Council (NHMRC) Centre of Research Excellence in Pulmonary Fibrosis, Australia; Department of Rheumatology, Royal Prince Alfred Hospital, Sydney, NSW, Australia. Electronic address: matthew.parker@health.nsw.gov.au.

Jane F Bleasel

Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; Department of Rheumatology, Royal Prince Alfred Hospital, Sydney, NSW, Australia. Electronic address: jane.bleasel@sydney.edu.au.

Lauren K Troy

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia. Electronic address: ltroy@med.usyd.edu.au.

Edmund M Lau

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia. Electronic address: edmundmtlau@gmail.com.

Helen E Jo

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; National Health and Medical Research Council (NHMRC) Centre of Research Excellence in Pulmonary Fibrosis, Australia. Electronic address: helen.jo@sydney.edu.au.

Alan K Y Teoh

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; National Health and Medical Research Council (NHMRC) Centre of Research Excellence in Pulmonary Fibrosis, Australia. Electronic address: alan_tky@yahoo.com.

Susanne Webster

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia. Electronic address: susanne.webster@health.nsw.gov.au.

Stephen Adelstein

Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; Central Immunology Laboratory, NSW Health Pathology, NSW, Australia; Department of Clinical Immunology and Allergy, Royal Prince Alfred Hospital, NSW, Australia. Electronic address: stephen.adelstein@sydney.edu.au.

Tamera J Corte

Department of Respiratory, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Central Clinical School, University of Sydney Faculty of Medicine and Health, Sydney, NSW, Australia; National Health and Medical Research Council (NHMRC) Centre of Research Excellence in Pulmonary Fibrosis, Australia. Electronic address: tameracorte@me.com.

References

PubMed