<qa>  What is the term for a disease called diffuse panbronchiolitis?The purpose of this study is to evaluate whether Biaxin clarithromycin improves sputum abnormalities, lung function, and overall feeling of well-being in people with cystic fibrosis CF. Biaxin is an antibiotic commonly used for the treatment of respiratory infections in people who do not have CF, and is sometimes used in CF patients as well. Studies done in a disease called diffuse panbronchiolitis which is similar to CF and some preliminary studies that have been done in CF patients suggest that Biaxin might have a beneficial effect on CF sputum in ways unrelated to its antibiotic activity. 