CSF2 and pulmonary alveolar proteinosis: In this study, idiopathic PAP was treated by subcutaneous injection of low-dose GM-CSF (75 μg/d or 150 μg/d, ie 1.25 μg/kg/d or 2.5 μg/kg/d, calculated according to 60 kg body weight), which was far lower than the dose reported by other studies.