Cellular analysis including lymphocyte surface markers in BALF in 17 patients with DPB (14 male; 36 female) was performed. The total number of cells increased remarkably, especially the percentage of neutrophils (72.9 +/- 14.1%). On the contrary the percentage of alveolar macrophage decreased (15.4 +/- 8.9%). The CD4/CD8 ratio in DPB was also significantly decreased to 0.73 +/- 0.38% when compared with normal healthy nonsmokers. Five patients with low dose and long term EM treatment were analyzed. Total cell counts as well as the neutrophil percentage (7.3 +/- 4.0%) decreased significantly. On the other hand the percentage of alveolar macrophage increased to 76.6 +/- 0.6%, which was almost similar to those obtained from normal healthy volunteers. Therefore it is concluded that both clinical and BALF findings improved concordantly after EM treatment.