Comprehensive assessment of myositis-specific autoantibodies in polymyositis/dermatomyositis-associated interstitial lung disease.
OBJECTIVES
Myositis-specific autoantibodies (MSAs) are associated with clinical phenotypes in polymyositis/dermatomyositis (PM/DM). No study has investigated the clinical features based on comprehensive MSA assessment in PM/DM-associated interstitial lung disease (ILD). We aimed to determine the practical significance of MSAs in PM/DM-ILD.


METHODS
Sixty consecutive PM/DM-ILD patients were retrospectively analysed. Serum MSAs were comprehensively measured using immunoprecipitation assay. Clinical features and prognosis were compared among MSA subgroups.


RESULTS
Twenty-six (43.3%) PM/DM-ILD patients were anti-aminoacyl tRNA-synthetase antibody-positive (anti-ARS-positive), 15 (25.0%) were anti-melanoma differentiation-associated gene 5 antibody-positive (anti-MDA5-positive), 3 (5%) were anti-signal recognition particle antibody-positive, 1 (1.7%) was anti-transcriptional intermediary factor 1-gamma antibody-positive, and 15 (25%) were MSA-negative. There were significant differences in clinical features, including ILD form, serum ferritin and surfactant protein-D levels at ILD diagnosis, and high-resolution CT pattern among the anti-ARS-positive, anti-MDA5-positive and MSA-negative groups. The anti-MDA5-positive group showed the lowest 90-day survival rate (66.7%, anti-MDA5-positive; 100%, anti-ARS-positive; 100%, MSA-negative; P < 0.01). The anti-ARS-positive group had the highest 5-year survival rate (96%, anti-ARS-positive; 66.7%, anti-MDA5-positive; 68.3%, MSA-negative, P = 0.02). Univariate analysis revealed that anti-ARS antibody was associated with better prognosis (HR = 0.45; 95% CI, 0.18-0.89; P = 0.02), whereas anti-MDA5 antibody was associated with poorer prognosis (HR = 1.90; 95% CI, 1.02-3.39; P = 0.04).


CONCLUSIONS
The comprehensive MSA assessment demonstrated that anti-ARS and anti-MDA5 antibodies were two major MSAs, and the clinical features differed depending on MSA status in PM/DM-ILD. Assessment of anti-ARS and anti-MDA5 antibodies is practically useful for predicting clinical course and prognosis in PM/DM-ILD patients.
['Hozumi|Hironao|H|', 'Fujisawa|Tomoyuki|T|', 'Nakashima|Ran|R|', 'Johkoh|Takeshi|T|', 'Sumikawa|Hiromitsu|H|', 'Murakami|Akihiro|A|', 'Enomoto|Noriyuki|N|', 'Inui|Naoki|N|', 'Nakamura|Yutaro|Y|', 'Hosono|Yuji|Y|', 'Imura|Yoshitaka|Y|', 'Mimori|Tsuneyo|T|', 'Suda|Takafumi|T|']
D000328:Adult D000368:Aged D000604:Amino Acyl-tRNA Synthetases D001323:Autoantibodies D015415:Biomarkers D003882:Dermatomyositis D005260:Female D006801:Humans D000072640:Interferon-Induced Helicase, IFIH1 D017563:Lung Diseases, Interstitial D008297:Male D008875:Middle Aged D017285:Polymyositis D011379:Prognosis D012189:Retrospective Studies D014057:Tomography, X-Ray Computed
Myositis-specific autoantibody Polymyositis Dermatomyositis ARS Interstitial pneumonia MDA5