Antisynthetase syndrome: An under-recognized cause of interstitial lung disease

Abstract

Background: Antisynthetase syndrome (AS) is an uncommon and under-recognised connective tissue disease characterized by the presence of antibodies to anti-aminoacyl t-RNA synthetase along with features of interstitial lung disease (ILD), myositis and arthritis. The aim of the current study is to describe our experience with management of AS. Materials and Methods: This was a 2-year (2013-2014) retrospective analysis of patients diagnosed with anti-Jo-1-related AS. The presence of anti-Jo-1 antibody was tested by the immunoblot assay. All patients underwent high-resolution computed tomography of the chest, transthoracic echocardiography and evaluation for inflammatory myositis. Transbronchial lung biopsies and muscle biopsies were obtained when clinically indicated. Results: Nine patients (mean age: 43.8 years) were diagnosed with anti-Jo-1-related AS. The median duration of symptoms before diagnosis of AS was 6 months. All patients were negative for antinuclear antibodies by indirect immunofluorescence. The prevalence of ILD, myositis and arthritis at presentation was 100%, 77.8% and 55.6%, respectively. The most common ILD pattern was non-specific interstitial pneumonia (n = 6) followed by organizing pneumonia (n = 2) and usual interstitial pneumonia (n = 1). ILD was the sole manifestation in two patients and was subclinical in two patients. Six patients had pleuropericardial effusions, three patients had pulmonary artery hypertension and two patients had venous thromboembolism. Eight of the nine patients improved after treatment with steroids and other immunosuppressants. Conclusion: Antisynthetase syndrome is an important and a treatable cause of ILD. Strong clinical suspicion is needed to achieve an early diagnosis.

Keywords

• Antisynthetase syndrome
• anti-Jo-1 antibody
• diffuse parenchymal lung disease
• inflammatory myositis
• interstitial lung disease
• non-specific interstitial pneumonia