INCREASE OF ACTIVATED T-CELLS IN BAL FLUID OF JAPANESE PATIENTS WITH BRONCHIOLITIS OBLITERANS ORGANIZING PNEUMONIA AND CHRONIC EOSINOPHILIC PNEUMONIA

To study the role of T cells in bronchiolitis obliterans organizing pneumonia (POOP) and chronic eosinophilic pneumonia (CEP) and to examine the influence of differing racial background, T-cell subsets in bronchoalveolar lavage (BAL) fluid (BALF) and in peripheral blood of 8 Japanese patients with idiopathic BOOP and 5 with CEP were compared with those of 15 normal subjects. The BALF pattern in BOOP was characterized by a significantly high number and percentage of lymphocyte and by a low CD4 to CD8 ratio compared with patients with CEP and healthy volunteers. Patients with CEP showed a significantly higher percentage of BALF eosinophils compared with other groups. There was no significant difference in BALF CD4 to CD8 ratio between patients with CEP and volunteers. Two-color analysis of T-cell subsets revealed that CD3(+)HLA-DR(+) cells (activated T cell) in BALF of patients with POOP and CEP increased significantly compared with volunteers, while BALF CD3(+)CD25(+) cells (interleukin 2 receptor(+) T-cell) did not. In addition, BALF CD8(+)HLA-DR(+) cells (activated suppressor/cytotoxic T cell) in patients with BOOP and CD4(+)HLA-DR(+) cells (activated helper T cell) in patients with CEP were significantly higher than levels detected in healthy subjects. The percentage of CD8(+)CD57(+) cells and the number of CD8(+)CD11b(-) cells (cytotoxic T cell) in BALF were significantly higher in patients with POOP compared with patients with CEP and healthy volunteers. There were no significant differences in the expression of peripheral blood T-lymphocyte surface antigens among the groups. These findings indicate that cytotoxic T cells in Japanese patients with idiopathic BOOP and helper T cells in CEP appear in the lungs is consistent with a previous report in Caucasians, supporting the hypothesis that T cells may play an important role in the pathogenesis of these diseases.