Fatal cases of pulmonary alveolar proteinosis: a nationwide surveillance in Japan

Background: Pulmonary alveolar proteinosis (PAP) is a chronic rare lung disease characterized by the intra-alveolar accumulation of surfactant lipids and proteins. 10 year survival of autoimmune PAP was 89.7% (n=117, WASOG, 2017) in our institute, however, we recently reported that fibrosis develops in approximately 20% of patients with PAP in their long clinical courses, and the prognosis of them was poor (AJR. 207:544, 2016). To clarify the characteristics of fatal cases of PAP, we retrospectively analyzed the diseases cases from our Japanese cohort database. Subject and methods: We collected 579 cases with PAP from 95 Japanese institutes, and 81 cases (14.0%) were dead. Within 81 cases, we collected the detail data from 34 cases. Results: 60% was autoimmune/idiopathic PAP, 34% was secondary PAP. Median age of 34 fatal cases (65% male) was 59 (range 28-82) years old. 59% was smokers (Current and former), and 21% had dust exposure. At the diagnosis, 21% of patients had interstitial pneumonia/pulmonary fibrosis (IP/PF), 21% had collagen vascular diseases, 18% had incfectious disease, 3% had malignant diseases. However during the followup periods, 9% had IP/PF, 24% had incfectious disease, 24% had malignant diseases. Causa of the death was 26% was malignantn diseases, 18% in fections, 12% was PAP, 6% IP/PF, 6% was cerebro vascular diseases. Conclusions: Patients with PAP had more comorbidities than previously reported. Managemnents of them would be cricial for better prognosis. Grant: This study was supported by the grant from AMED #17930161 (YI)