Long-Term Macrolide Antibiotic Therapy in the Treatment of Chronic Small Airway Disease Clinically Mimicking Diffuse Panbronchiolitis

Objective In the current studies, we investigated the clinical effects of long-term macrolide antibiotic therapy for patients with chronic small airway disease (CAD) that clinically and radiologically mimics but is pathologically distinct from diffuse panbronchiolitis (DPB).Patients and Methods Twenty-one Japanese patients were selected on the basis of clinical criteria for DPB and were categorized as DPB or CAD following histological evaluation of surgical lung biopsies. All patients received long-term macrolide therapy, and therapeutic results were compared for the DPB and CAD groups.Results Clinical, laboratory, radiological, and bacterial features, as well as neutrophilia in bronchoalveolar lavage fluid were strikingly similar in both groups. Long-term treatment with macrolides improved the clinical symptoms and PaO2 in both groups. There was a significant improvement in forced expiratory volume in one second (FEV1), vital capacity (VC), and %VC in patients with DPB but not in patients with CAD. Neutrophilia in bronchoalveolar lavage fluid was also reduced following therapy in DPB patients but was refractory in CAD patients.Conclusion Based on the different responses to macrolides, CAD might be associated with conditions distinct from those of DPB. Nevertheless, low-dose macrolide therapy may be applied in CAD to achieve clinical improvement, such as in respiratory symptoms and PaO2.