Diffuse panbronchiolitis--pathophysiology and treatment mechanisms.

Diffuse panbronchiolitis (DPB) is a chronic, potentially life-threatening lower respiratory tract disease that is particularly common in Japanese people. It is characterized by chronic infiltration of inflammatory cells, and Pseudomonas aeruginosa is isolated from sputum in some cases. Bronchoalveolar lavage fluid from DPB patients contains high concentrations of neutrophils, lymphocytes and inflammatory cytokines compared with levels found in other chronic lung diseases. If left untreated, DPB progresses rapidly and is usually fatal, but long-term, low-dose macrolide therapy improves the prognosis. Macrolides are effective against DPB even in the absence of a P. aeruginosa infection. There is evidence that these antibiotic agents may have an anti-inflammatory mode of action in DPB.