Autoimmune Pulmonary Alveolar Proteinosis during the Treatment of Idiopathic Inflammatory Myopathy

Abstract

Approximately 50% of idiopathic inflammatory myopathies (IIMs) are associated with interstitial lung disease (ILD). Typically, IIM-ILD manifests as nonspecific interstitial pneumonia. We herein report a rare case of a 78-year-old man with autoimmune pulmonary alveolar proteinosis (PAP) that developed during IIM treatment. The diagnosis of autoimmune PAP was based on detecting anti-granulocyte-macrophage colonystimulating factor antibodies. We postulated that PAP may have been induced by IIM treatment with prednisolone. Our case suggests that the possibility of autoimmune PAP should be considered in patients with lung lesions during the clinical course of IIM.

Pulmonary alveolar proteinosis during treatment of immune‐mediated necrotizing myopathy

“…Among 12 cases of APAP associated with connective tissue disease, 6 cases had IIMs (including this case). [7][8][9][10] A crazy-paving pattern on CT is a characteristic finding of PAP, but it is occasionally found in patients with ILD. 1 Among patients with IMNMs, ILD was found in 20%-40% of anti-SRP antibody-positive cases, but in less than 5% of anti-HMGCR antibody-positive cases.…”