Abstract
Diffuse panbronchiolitis (DPB) is characterized by a dense neutrophil infiltration in association with the high level of interleukin 8 (IL-8) in the airway and an accumulation of lymphocytes, especially CD8+HLA-DR+cells. In this study, we demonstrated that IL-8 mRNA was expressed in alveolar macrophages in the air space, bronchiolar epithelial cells and endothelial cells by in situ hybridization method, while not in foamy macrophages in the interstitium. A two-color analysis of T cell subsets in bronchoalveolar lavage (BAL) fluid also revealed a significant increase in the number of CD8+CD11b- cytotoxic T cells and CD4+CD29+ memory T cells and the mean fluorescence intensity of CD49d (very late antigen, VLA-4α) on CD4+cells in the patients. Furthermore, the level of RANTES and MIP-1α in DPB patients was significantly higher than that in healthy volunteers, and there was a trend toward a correlation between RANTES concentration and the absolute number of memory T cells in BAL fluid (r=0.731, p=0.188) .
Our results suggest that elevation of memory T cells and cytotoxic T cells, in addition to neutrophils, in the airway lumen of DPB patients may contribute to chronic bronchial inflammation, possibly through up-regulation of adhesion molecule, VLA-4 and chemokines produced in the lung.
