Clinical, radiological, and pathological features of anti-asparaginyl tRNA synthetase antibody-related interstitial lung disease

Background: Myositis and interstitial lung disease (ILD) frequently occur in patients with anti-aminoacyl-tRNA synthetase (ARS) antibodies. Nearly half of ARS-ILD patients have the acute or subacute form of the disease, and one-third of these patients show a deterioration in pulmonary function over the long-term course because of frequent recurrences and refractoriness to therapy. Several reports recently described different characteristics depending on the individual anti-ARS antibodies, and the anti-asparaginyl tRNA synthetase (KS) antibody was strongly linked to ILD rather than to myositis. We therefore hypothesized that KS-ILD may have clinical characteristics that differ from those of other ARS-ILDs. The aim of this study was to clarify the clinical, radiological, and pathological features of KS antibody-positive ILD.

Methods: We retrospectively analyzed 19 consecutive patients with KS-ILD who underwent initial clinical measurements and high-resolution computed tomography and pathological assessments. We also analyzed disease behavior based on pulmonary function test results during the follow-up period.

Results: Our KS-ILD cohort included patients with dermatomyositis (10.5%), primary Sjögren syndrome (5.3%), and idiopathic ILD (84.2%). Most patients presented with chronic onset (89.5%) and a nonspecific pattern of interstitial pneumonia at each radiological and pathological assessment (89.4% and 85.7%, respectively). The pulmonary function test results showed that the mean changes from the initial %forced vital capacity and %diffusing capacity of the lung for carbon monoxide at 3 years were 3.7% ± 2.9% and 9.35% ± 3.0%, respectively.

Conclusions: Most KS-ILD patients showed a tendency for chronic disease onset and long-term stabilization of pulmonary function.