Therapeutic effect of subcutaneous injection of low dose recombinant human granulocyte-macrophage colony-stimulating factor on pulmonary alveolar proteinosis

OBJECTIVE: To observe the efficacy of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) for pulmonary alveolar proteinosis (PAP). MATERIALS AND METHODS: A total of 55 patients with PAP were screened at Shanghai Pulmonary Hospital between May 2014 and May 2018. Among these, 42 were diagnosed with idiopathic PAP, 24 were included in this study, 20 were treated for 6 months, and 17 were followed up for additional 6 months. All patients received a subcutaneous injection of 75μg/d GM-CSF qd for 1 month. The therapeutic dose was adjusted according to the changes in the lesions of chest CT. If the lesions were absorbed, subcutaneous injections of 75μg/d GM- CSF qd and 75μg/d GM-CSF qod were given for 2 and 3 months, otherwise, the dose was increased to 150μg/d GM-CSF qd and 150μg/d qod for 2 and 3 months, respectively. All cases were treated once a day in the first 3 months and once every other day in the last 3 months. The total course of treatment was 6 months. After withdrawal, the patients were followed up for another 6 months. The deadline of follow up was September 30, 2019. RESULTS: Twenty patients completed the treatment and efficacy evaluation. One patient was completely cured, 16 cases improved, three cases were noneffective. After 1-month evaluation, 12 patients received an increased dose (150μg) from the second month of treatment. Seventeen patients completed the 12-month follow-up, among which fourteen improved. CT showed the lesions were slightly increased in three cases. Economic burden was the following: RMB 7324–15,190 Yuan were required for the 6-month treatment course, which is significantly lower compared to other treatment methods. CONCLUSION: Subcutaneous injection of rhGM-CSF at low dose (75μg-150μg /d) is effective treatment for patients with idiopathic PAP. TRIAL REGISTRATION: NCT01983657. Registered 16 April 2013.