Induced sputum deposition improves diagnostic yields of pulmonary alveolar proteinosis: A clinicopathological and methodological study of 17 cases.

ABSTRACTPulmonary alveolar proteinosis (PAP) is a rare diffuse lung disease characterized by the accumulation of intra-alveolar lipoprotein-like surfactants. Lung core biopsy and bronchoalveolar lavage (BAL) fluid are currently the two major sources of sampling for diagnosis. In the present study, we assessed the value of induced sputum in diagnosing PAP by transmission electron microscopy and examined the PAP 2-year death rate in Asians. Transmission electron microscopy was performed on the samples from 17 patients with PAP, 13 patients with inflammatory lung diseases, and 13 healthy adults. The PAP patients were followed up for 3–156 months, and inflammatory lung diseases patients or healthy adults for 12–36 months. The ultrastructural features including diagnostic lamellar bodies of induced sputum deposition (ISD) samples were similar to that of the BAL fluid sediment. However, the rates of lamellar bodies were 73.7% in the ISD group, significantly higher than the spontaneous sputum deposition (SSD) gr...