Because of the reported risk of subcutaneous GM-CSF in patients who are immunosuppressed1 and the suggestion of safety with the aerosolized form of GM-CSF in such patients,2 we initiated the use of aerosolized GM-CSF with 250 μg bid Leukine (Immunex Corporation): 1 week on and 1 week off for 3 months. A chest CT scan 4 weeks after starting this therapy showed complete resolution of the ground-glass opacities. Lung function studies revealed an FVC of 3.42 L (95% predicted), a Dlco of 70% predicted, and a 6-min walk of 337 m with a saturation of 97% on room air with walking. At a 6-month follow-up visit, the patient continued to be without dyspnea, cough, or exercise intolerance. Her lung function studies 9 months after presentation demonstrated an FVC of 3.66 L (102% predicted), a Dlco of 71% predicted, and a 6-min walk of 346 m. She remained on standard immunosuppressive therapy without a GPA relapse.