Anti-Ha anti-synthetase syndrome presenting as rapidly progressive interstitial lung disease: a case report of high confidence autoantibody testing.

We report on a 38-year-old patient who presented with rapidly progressive interstitial lung disease (ILD), without any signs of muscular involvement. Antinuclear antibody testing by indirect immunofluorescence revealed a nuclear titer of 1:320 with a fine speckled and a cytoplasmic titer of 1:1'280 with a fine speckled pattern. Subsequent myositis-specific and myositis-associated antibody tests with commercial multiplex dot-immunoassays showed a strong positive result for anti-Ha antibodies, also confirmed by protein immunoprecipitation, establishing the diagnosis of anti-synthetase syndrome with associated ILD. Despite initial improvement after treatment with intravenous cyclophosphamide and high dose steroids, he relapsed shortly after, with additional muscular symptoms. Subsequent escalation of therapy with rituximab resulted in sustained remission. Considering the scarcity of data about the clinical presentation and prognosis of patients with anti-Ha antibodies, our report provides additional information on diagnostic challenges and therapeutic response in these patients.