Glycosylation of sputum mucins is altered in cystic brosis patients

Cystic brosis (CF) is characterized by chronic lung infection and in. ammation, with periods of acute exacerbation causing severe and irreversible lung tissue damage. We used protein and glycosylation analysis of high- molecular mass proteins in saline- induced sputum from CF adults with and without an acute exacerbation, CF children with stable disease and preserved lung function, and healthy non- CF adult and child controls to identify potential biomarkers of lung condition. While the main high-molecular mass proteins in the sputum from all subjects were the mucins MUC5B and MUC5AC, these appeared degraded in CF adults with an exacerbation. The glycosylation of these mucins also showed reduced sulfation, increased sialylation, and reduced fucosylation in CF adults compared with controls. Despite improvements in pulmonary function after hospitalization, these differences remained. Two CF children showed glycoprotein pro. les similar to those of CF adults with exacerbations and also presented with pulmonary. ares shortly after sampling, while the remaining CF children had pro. les indistinguishable from those of healthy non- CF controls. Sputum mucin glycosylation and degradation are therefore not inherently different in CF, and may also be useful predictive biomarkers of lung condition.