[Dermatomyositis associated with rapid progression of pulmonary involvement]

In this case series we present three patients with autoimmune dermatomyositis or polymyositis with rapid-progressive interstitial pulmonary involvement. Despite intensive escalation of the immunosuppressive therapy the patients developed acute respiratory distress syndrome with lethal outcome only a few months after diagnosis. All three patients had increased myositis-specific or myositis-associated antibodies - two patients were detected with anti-melanoma differentiation-associated gene (MDA5) antibodies and the third patient with anti-Ku antibodies. Dermatomyositis and polymyositis are rare autoimmune diseases with variable clinical manifestations and several different antibody constellations. In particular the presence of anti-MDA5 antibodies is associated with progressive pulmonary involvement, complicated progression and poor prognosis.