The clinical phenotype associated with antisynthetase autoantibodies

Specific systemic autoimmune syndrome characterized by inflammatory myopathy, arthritis or arthralgias, interstitial lung disease (ILD), fever, Raynaud's phenomenon, and mechanic's hands is called antisynthetase syndrome (AS). The aim of this study was to assess the clinical spectrum associated with presence of aminoacyl-transfer RNA synthetase autoantibodies (ASA).

A total of 305 patients with presence of myositis-specific autoantibodies were identified in the database of immunological tests performed in the Clinical Immunology and Transplantology Unit, Medical University of Gdansk between January 2011 and March 2016. In 110 patients (36%) ASA were detected. The detailed analysis included 50 patients with ASA for whom full clinical data were available.

The incidence of specific ASA in the analyzed group was: Jo-1 46% (23 patients), PL-12 32% (16 patients), PL-7 16% (8 patients), OJ 12% (6 patients), EJ 6% (3 patients). In 10% (5 patients) there was coexistence of at least one ASA, and in another 5 patients there was coexistence of ASA with other antibodies specific for myositis (MSA). In the analyzed group of patients 11 (22%) satisfied the Bohan and Peter criteria for dermatomyositis, 1 for polymyositis. In 5 patients (10%) based on clinical presentation and ASA presence the AS was recognized. Another 3 patients met the criteria of the overlap syndrome polymyositis respectively with systemic lupus, rheumatoid arthritis, and scleroderma. In 5 patients undifferentiated connective tissue disease was diagnosed, and 14 consecutive patients were diagnosed with other connective tissue diseases, while 12 patients did not receive a definitive diagnosis.

The clinical presentation of patients with the presence of ASA is varied. Their presence indicates not only idiopathic inflammatory myopathies, but also non-specifically other disease entities. These patients require observation for the development of idiopathic inflammatory myopathy, and ILD.