To study the role of T cells in diffuse panbronchiolitis (DPB), we investigated T-cell subsets in bronchoalveolar lavage fluid (BALF) or 33 patients with DPB, nine patients with bronchiectasis, and 20 healthy volunteers. BALF from DPB patients contained a higher percentage of neutrophils than that from patients with bronchiectasis or healthy volunteers, whereas the percentage of lymphocytes was similar in the three groups. DPB patients, however, had a higher number of lymphocytes and a reduced CD4/CD8 ratio compared with the other subjects. A two-color analysis of T-cell subsets in peripheral blood and BALF revealed a significant increase in the percentage and number of CD8+HLA-DR+ cells and in the number of CD4+HLA-DR+ cells in BALF of DPB patients. The expression of the adhesion molecules CD 11a and CD18 on lung CD3+ cells was enhanced over that on blood CD3+ cells in DPB patients. However, there was no significant difference in the expression of these antigens in peripheral blood or BALF among the groups. There was no significant relationship between BALF interleukin (IL)-8 and lymphocyte accumulation in the lungs of the DPB patients, whereas a significant correlation between the percentage of neutrophils and IL-8 levels in BALF of DPB patients was observed. After treatment with macrolide antibiotics, a significant reduction in the number of lymphocytes and activated CD8+ cells and an elevation in the CD4/CD8 ratio in BALF of DPB patients was observed. Our findings suggest an activation of CD8+ cells in the airway lumen of DPB patients, supporting the hypothesis that lymphocytes are important cellular components of bronchial inflammation in DPB.

To evaluate the effects of roxithromycin in patients with chronic lower respiratory tract disease including diffuse panbronchiolitis, we studied lymphocyte function-associated antigen-1 (LFA-1) and Mac-1, neutrophil adhesion molecules, using peripheral neutrophils from healthy volunteers and from patients with chronic lower respiratory tract disease. The number of Mac-1 expressed on neutrophils of the patients was significantly greater (0.68 ± 0.16) than in the healthy subjects (0.45 ± 0.14), while the number of LFA-1 expressed on neutrophils of the patients was nearly similar to that in the healthy volunteers (0.95 ± 0.10 vs. 0.89 ± 0.11). The neutrophil numbers in bronchoalveolar lavage fluid and the number of Mac-1 expressed on peripheral neutrophils significantly decreased in all patients who responded clinically to a low dose of roxithromycin for a long period of time (56.0 ± 25.2 vs. 22.7 ± 19.7%, p < 0.05 and 0.70 ± 0.16 vs. 0.59 ± 0.08, p < 0.05, respectively), whereas roxithromycin had no effect on the quantitative expression of LFA-1 (0.96 ± 0.14 to 1.00 ± 0.09, not significant) in all responders.

IL-ƒÀ p<0.05). These cytokines showed a decrease after RXM treatment. These results indicated that RXM acts by reducing pulmonary inflammation through reduction of neutrophil migration to inflammatory sites, and is effective on chronic lower respiratory tract disease.

We have recently reported that long-term administration of erythromycin at a low dose reduced the number of neutrophils and concentrations of interleukin 8 (IL-8) in bronchoalveolar lavage fluid in patients with chronic lower respiratory tract disease. To investigate the mechanism of action of erythromycin, we evaluated its effect on IL-8 production in the 1 alpha,25-dihydroxyvitamin D3-stimulated human monocytic cell line THP-1. Erythromycin at a concentration of 10 micrograms/ml significantly reduced IL-8 production by THP-1 cells stimulated with lipopolysaccharide (10 ng/ml) and 1% normal human serum compared with the amount produced by untreated cells (untreated cells, 2,448 pg/ml; erythromycin-treated cells, 872 pg/ml). Our results suggest that erythromycin may impair IL-8 production by alveolar macrophages, ultimately reducing neutrophil accumulation in the airspace.

No abstract