ABSTRACT
Diffuse panbronchiolitis (DPB) is a pulmonary disease characterized by chronic inflammation of the bronchioles and chronic infiltration of inflammatory cells in the lungs. Macrolides are effective therapeutic agents for chronic respiratory tract diseases, such as DPB. However, the mechanisms by which macrolides modulate the immune responses in patients with DPB remain unclear. To understand clinical efficacy for the treatment of DPB by macrolides, the effects of erythromycin (EM) on the expression of pro-inflammatory cytokines such as interleukin-6 (IL-6) and interleukin-8 (IL-8) by human neutrophils were examined. Pre-treatment with EM significantly decreased the expression of IL-6 and IL-8 transcripts by lipopolysaccharide (LPS)-stimulated human neutrophils. EM also reversed the enhanced survival of human neutrophils by LPS. These data indicate that EM has achieved therapeutic effect for patients with DPB, in part, through decreasing the expression of pro-inflammatory cytokines and the survival of neutrophils.