The present invention provides methods for enhancing pulmonary host defense in a subject by administering via inhalation an effective amount of granulocyte-macrophage colony stimulating factor or a functional homologue thereof. Methods of the present invention are useful in alleviating symptoms and/or treating pulmonary diseases or conditions including, but not limited to lung cancer, pneumocystis carinii, pneumonia with or without bacterial, fungal and/or viral infection including but not limited to community acquired pneumonia, nosocomial pneumonia or ventilator associated pneumonia, and or cystic fibrosis with or without bacterial, fungal and/or viral infection or colonization, bronchitis, Bronchiectasis, Diffuse panbronchiolitis, Bronchiolitis, Bronchiolitis obliterans, Bronchiolitis obliterans organizing pneumonia (BOOP) and/or bacterial, fungal and/or viral colonization or infection.
