Overproduction of MUC5AC Core Protein in Patients with Diffuse Panbronchiolitis

BACKGROUND: The genetic identities of mucins secreted in the airways of patients with diffuse panbronchiolitis (DPB) have not been previously investigated, although hypersecretion is a common feature of this disease. OBJECTIVE: The purpose of this study was to determine the production of MUC5AC, a major core protein of mucin in airway secretion, and the effect of macrolide treatment on such production in patients with DPB. METHOD: We performed Western blot analysis for MUC5AC of bronchoalveolar lavage fluid patients. Cases consisted of four groups including patients with DPB, idiopathic pulmonary fibrosis (IPF), and sarcoidosis, and healthy volunteers. RESULTS: MUC5AC was detected in DPB patients but not in other groups. Macrolide treatment tended to inhibit such production in DPB patients. CONCLUSIONS: Our results suggest that overproduction of MUC5AC plays an important role in the pathogenesis of DPB.