Background:
Inflammatory myositis (IIM) is a rare condition. It can be associated with other disease such as interstitial lung disease and malignancy. Autoantibodies specific for IIM, or myositis specific antibodies (MSAs), are useful biomarkers that assist with clinical diagnosis. The utility of MSA has increased as new autoantibodies are being discovered over the last decade. At the same time, there is growing anecdotal report of false positive MSA. Currently there is no data on the positive predictive value of MSA in general clinical scenario where the overall prevalence of inflammatory myositis is low.
Methods:
This is a retrospective review of patients tested for MSA from St George Hospital, The Sutherland Hospital and Prince of Wales Hospital between 2017 and 2019. MSA is performed by South East Sydney Area Laboratory Service (SEALS) using Autoimmune Inflammatory Myopathies Immunoblot from Euroimmun, detecting the following antibodies: Ro52, OJ, EJ, PL-12, PL-7, SRP, Jo-1, PM-Scl75, PM-Scl100, Ku, SAE1, NXP2, MDA5, IF1, MI-2beta, MI-2alpha. Other data extracted from SEALS includes the corresponding ESR, CRP, ANA, ENA, and CK. Medical records of MSA-positive patients will be reviewed to identify those who with the following condition: dermatomyositis, polymyositis, inclusion body myositis, clinically amyopathic dermatomyositis, interstitial pneumonitis with autoimmune features, and interstitial lung disease. This is defined through conventional diagnostic criteria from a combination of clinical, radiological and histological findings.
Results:
TBA
Conclusions:
TBA