Inhalation of Granulocyte-macrophage Colony-stimulating Factor (GM-CSF) for Autoimmune Pulmonary Alveolar Proteinosis (PAP)

Accessible population:

Adult patients with mild-to-moderate autoimmune pulmonary alveolar and without spontaneous remission will be enrolled at Peking Union Medical College Hospital and Nanjing Drum Tower Hospital.

Inclusion Criteria:

• Adult autoimmune PAP subjects will be included: 1) a positive PAS stain from BALF or lung biopsy; 2) high level of serum anti-GM-CSF antibody (>2.39ug/ml, the cut-off point in our hospital); 3) age above 18 years old; 4) exclude hereditary and secondary PAP.
• Able to give written informed consent and comply with the requirements of the study.
• Patients are not eligible for the whole lung lavage (WLL), decided by clinicians.
• Eligibility for GM-CSF inhalation: 1) Disease severity score (DSS) is 1-3; 2) No treatment with GM-CSF therapy or WLLin the 3 months prior to enrollment. Definition of DSS2: 1, no symptom and PaO2>=70mmHg；2, PaO2>=70mmHg with symptoms；3, PaO2>=60 and <70mmHg; 4, PaO2>=50 and <60mmHg; 5, PaO2<50mmHg.

Exclusion Criteria:

• Patients will be observed for 3 months and all APAP patients who resolved spontaneously will be excluded from our study.
• PAP resulting from another condition (e.g. occupational exposure to silica, underlying HIV, respiratory infections, myeloproliferative disorder or leukaemia);
• A normal or low-titre serum anti-GM-CSF antibody (≤2.39ug/ml);
• History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies；
• Chronic lung disease associated with already existing respiratory failure (such as pulmonary emphysema or fibrosis);
• Other serious medical conditions which, in the opinion of the investigator, would make the patient unsuitable for the study.
• Pregnancy.