By updating the chest HRCT scoring criteria of patients with pulmonary alveolar proteinosis, a new and more perfect system for evaluating the severity of alveolar proteinosis will be established.

In past, investigators summarized a method that was the severity and prognosis of pulmonary alveolar proteinosis (SPSP) to assess the severity and prognosis of patients with autoimmune pulmonary alveolar proteinosis (auto PAP). The SPSP included five aspects: smoking, symptom, PaO2, chest CT score at specific levels (aortic arch, carina, pulmonary vein confluence, and superior septal level) and DLCO %predicted. But the chest CT score only focused on range of lesions, and inaccurate. So, investigators plan to adopt new score which involves the assessing to range and density.

In the new Chest HRCT score, we added the density score. The average density of the lesions at a particular level of the patient's chest HRCT was measured by computer and classified into three degrees: mild (less than -400), moderate (greater than -400 and less than -100) and severe (greater than 100), denoted as 1 ', 2 'and3', respectively.

The range score of lung opacity was estimated using a five-point scale: no opacity = 0; opacity involving < 25% of a region of hemithorax = 1; 25-50% = 2; 50-75% = 3; and ≥ 75% = 4.

The lesion score for each layer is equal to the density score multiplied by the range score. The chest HRCT score was calculated by summing the lung opacity scores of the four representative regions of each hemithorax, and divided into several level: no opacity = 0; ≤10 = 1; 11 - 20 = 2; 21 - 30 = 3; 31 -40 = 4; > 40 = 5.

According to the new chest HRCT score, the SPSP will be updated to SPSP II. In this study, patients with auto PAP from three centers (Shanghai Lung Hospital, Peking Union Medical College Hospital and Nanjing Drum Tower Hospital) were enrolled to evaluate the severity of disease severity score (DSS), SPSP and SPSP II, respectively, to evaluate the pros and cons of different scores and their impact on prognosis.

About 30 newly diagnosed auto PAP patients were recruited, and were assess disease severity on the basis on SPSP II scores. According to SPSP II scores, appropriate treatment was used for the patients, who were followed up for 3 months.

Inclusion Criteria:

• The patients had be diagnosed with autoimmune pulmonary alveolar proteinosis through pathology or bronchial alveolar lavage fluid (BALF).
• The patients are old than 18 year.
• .Every patient had a complete medical history, chest HRCT, pulmonary function and arterial blood gas analysis.
• The patients have high level antibody of GM-CSF in serum or BALF.

Exclusion Criteria:

• The patients had a congenital or secondary pulmonary alveolar proteinosis.

The patients had be diagnosed with autoimmune pulmonary alveolar proteinosis. Every patient had a complete medical history, chest HRCT, pulmonary function and arterial blood gas analysis.