BACKGROUND: Pulmonary alveolar proteinosis (PAP) is characterized by an abnormal accumulation of surfactants in the alveoli. Most cases are classified as autoimmune PAP (APAP) because they are associated with autoantibodies against granulocyte-macrophage colony-stimulating factor (GM-CSF). However, GM-CSF autoantibody levels are unlikely to correlate with the disease severity or prognosis of APAP.
METHODS: We collected clinical records and measured 38 serum cytokine concentrations for consecutive patients with APAP. After exclusion of 21 cytokines because of undetectable levels, 17 cytokine levels were compared between low and high disease severity scores (DSSs). We also compared whole lung lavage (WLL)-free survival with cut-off values defined by receiver operating characteristic (ROC) curves of cytokine levels and WLL administration at 11 months.
RESULTS: Nineteen patients with APAP were enrolled in the study. Five were classified as DSS 1 or 2, while the others were classified as DSS 4 or 5. Comparison between DSS 1-2 and 4-5 revealed that the concentrations of IP-10 and GRO increased in the latter groups (p < 0.05). Fifteen patients underwent WLL. Comparison between those who underwent WLL within 11 months and the others showed that IP-10 and TNF-α were tended to be elevated in the former group (p = 0.082 and 0.057, respectively). The cut-off values of IP-10, 308.8 pg/mL and TNF-α, 19.1 pg/mL, defined by the ROC curves, significantly separated WLL-free survivals with log-rank analyses (p = 0.005).
CONCLUSIONS: The concentrations of IP-10 and GRO may reflect the DSSs of APAP. A combination of IP-10 and TNF-α levels could be a biomarker to predict WLL-free survival.

Although pulmonary alveolar proteinosis (PAP) showed various shadows, its shadows are usually distributed predominantly in the central lung area. We report a case of autoimmune PAP with localized subpleural ground-glass shadows in the bilateral upper lobes, which was diagnosed based on transbronchial lung biopsy (TBLB) specimen findings and anti-granulocyte macrophage colony PAP stimulating factor antibody positivity. PAP should be listed as a differential diagnosis for subpleural shadows. If subpleural shadows are observed, TBLB should be performed aggressively, and anti-granulocyte macrophage colony-stimulating factor (anti-GM-CSF) antibodies should be submitted.

Herein, we report the case of a 73-year-old woman with an occupational history of plaster grinding who developed autoimmune pulmonary alveolar proteinosis (PAP) during the treatment of fibrotic hypersensitivity pneumonitis with steroids and immunosuppressive drugs. Based on the changes in computed tomography imaging findings, poor response to steroid therapy, and markedly elevated KL-6 levels, PAP was suspected and diagnosed by bronchoscopy. Repeated segmental bronchoalveolar lavage under high-flow nasal cannula oxygen therapy resulted in slight improvement. Steroids and immunosuppressive treatments for other interstitial lung diseases may cause PAP or exacerbate latent PAP.

A 58-year-old woman with cough and dyspnea who was suspected of having idiopathic interstitial pneumonia had been treated with corticosteroids and cyclosporine, but the symptoms had worsened. There were no findings to suspect pulmonary alveolar proteinosis (PAP) in the bronchoalveolar lavage fluid, 17 months after the start of treatment. The transbronchial lung biopsy specimens showed eosinophilic bodies that strongly stained with periodic acid-Schiff staining. Anti-granulocyte macrophage colony-stimulating factor (anti-GM-CSF) antibodies were detected in her serum. We diagnosed the patient with autoimmune PAP. Thus, we present a rare case of PAP presenting atypical radiological images and bronchoalveolar lavage fluid findings.

We herein report a case of autoimmune pulmonary alveolar proteinosis (PAP) diagnosed after one-time exposure to silica powder. Owing to the misuse of a silica-containing fire extinguisher and the inhalation of large amounts of its powder, the patient experienced prolonged cough and visited our hospital. The findings of chest computed tomography and surgical lung biopsy specimens led to the diagnosis of PAP. Interestingly, the presence of anti-GM-CSF antibody was detected; therefore, both autoimmune characteristics and exposure to large amounts of silica may have caused the development of PAP in this patient. This case provides important insight into the mechanisms leading to the onset of PAP.

A 65-year-old Japanese man was referred to our hospital for the further assessment of cough and dyspnea. He had a history of ulcerative colitis for which he was receiving treatment. Chest computed tomography showed a crazy-paving pattern. His bronchoalveolar lavage fluid had a milky appearance, and a transbronchial lung biopsy specimen revealed acellular periodic acid-Schiff stain-positive bodies. The serum anti-granulocyte macrophage-colony stimulating factor (GM-CSF) antibody titer was elevated. The diagnosis was autoimmune pulmonary alveolar proteinosis (PAP). There are few reports of autoimmune PAP in patients with ulcerative colitis. Some reports suggest that PAP and inflammatory bowel disease might have a common pathogenesis involving the anti-GM-CSF antibody.