[Response of dermatomyositis with lung involvement to Janus kinase inhibitor treatment].

We report on a 32-year-old male patient presenting with anti-MDA-5 and anti-Ro52 antibody positive hypomyopathic dermatomyositis (CADM) with clinically leading interstitial pulmonary involvement. Under several immunosuppressive treatment regimens including high-dose steroids, cyclophosphamide, rituximab, immunoglobulins, plasmapheresis, ciclosporin and mycophenolate mofetil, pulmonary involvement was refractory to progressive. Based on the detection of a clear-cut interferon signature by flow cytometric determination of SIGLEC-1 as an interferon-dependent marker, treatment with the Janus kinase inhibitor tofacitinib was initiated. This resulted in a response to treatment with a significant increase in physical performance, an ameliorated skin condition and computed tomographic (CT) morphologically improved interstitial lung disease with overall good tolerability.