Two cases of autoimmune and secondary pulmonary alveolar proteinosis during immunosuppressive therapy in dermatomyositis with interstitial lung disease.

Interstitial lung disease (ILD) with dermatomyositis often requires intensive immunosuppressive therapy. Here, we report two cases of pulmonary alveolar proteinosis (PAP) in dermatomyositis with ILD. One case was secondary PAP, and the other was autoimmune PAP positive for the anti-granulocyte macrophage-colony-stimulating factor antibody. PAP arose during immunosuppressive therapy and symptoms ceased by attenuating immunosuppression. Exacerbation of pulmonary lesions during intensive immunosuppressive therapy may distinguish PAP from worsening ILD and attenuating immunosuppression should be considered.