The role of myositis-specific autoantibodies and The Management of Interstitial Lung Disease in idiopathic inflammatory myopathies: A systematic review

Objective: To evaluate the role of myositis-specific autoantibodies (MSAs) in interstitial lung disease (ILD), management of idiopathic inflammatory myopathies (IIM) associated ILD, and if there is a role for MSA specific management of ILD. Methods: A systematic review was performed examining how MSAs relate to ILD manifestations in IIM patients and comparing treatment outcomes with varying immunosuppressive regimens. Results: 112 papers were included in this analysis. Patients with anti-aminoacyl tRNA synthetase (anti-ARS) and anti-melanoma differentiation-associated gene 5 (anti-MDA5) antibodies had consistently higher rates of ILD than other MSA groups. Anti-ARS positive patients had higher rates of chronic ILD whereas anti-MDA5 positive patients had higher rates of rapidly progressive ILD (RP-ILD). The most common high-resolution computed tomography (HRCT) patterns for ILD in anti-ARS and anti-MDA5 positive patients were nonspecific interstitial pneumonia (NSIP) and unclassifiable respectively. Anti-transcription intermediary factor 1-gamma (anti-TIF1-gamma), anti-Mi-2, anti-nuclear matrix protein 2 (anti-NXP-2), and anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (anti-HMGCR) antibodies were associated with a decreased risk of ILD. Small sample sizes, a lack of head-to-head trials, and non-randomized designs prevented drawing meaningful conclusions with respect to immunosuppressive management. Conclusion: Clear relationships exist with regards to the ILD manifestations of certain MSAs. Standard therapy for IIM associated ILD (IIM-ILD) is glucocorticoids with the addition of others immunosuppressives in patients with or at risk of RP-ILD as well as in refractory cases. Immunosuppressives should be preferentially used in MSA populations in which they have been studied and shown to be efficacious.