Abstract

Introduction: Autoimmune pulmonary alveolar proteinosis (APAP) is caused by macrophage dysfunction due to anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibody. APAP complicated with sarcoidosis is rarely reported. Subject and Methods: We have diagnosed two cases of APAP complicated with sarcoidosis. We have measured serum levels of anti-GM-CSF autoantibody in our institute, and investigated the changes of its serum levels during the clinical course. Results: Case 1 is 42-years old female and Case 2 is 51-years old male at the diagnosis of sarcoidosis. Serum anti-GM-CSF antibody was positive in both cases. Case 1 was a typical APAP diagnosed at the age of 29 with milky bronchoalveolar lavage and crazy paving pattern on high-resolution CT. APAP was resolved after GM-CSF inhalation therapy at the age of 30 and sarcoidosis with lung, skin and eye lesions, occurred after the 10-year stable period of APAP. Case 2 was diagnosed as APAP and sarcoidosis, simultaneously. Surgical lung biopsy specimens showed granulomatous lesion consistent with sarcoidosis and intra-alveolar Periodic Acid Schiff stain-positive proteinaceous material compatible with APAP. Sarcoidosis lesions were also observed in skin and eye. In both cases, serum levels of angiotensin converting enzyme was decreased and dyspnea with hypoxemia was improved after the corticosteroid therapy. In both cases, APAP lesions were limited and serum levels of anti-GM-CSF antibody was low at the diagnosis of sarcoidosis. Conclusions: Anti-GM-CSF autoantibody was associated with clinical couse. Financial support: This study was partially granted from AMED to Y. Inoue and T. Arai.