The clinical features of sarcoidosis vary in different ethnic groups, suggesting that different genetic or environmental backgrounds influence the disease. In Scandinavian sarcoidosis patients, we have previously described a correlation between lung-accumulated CD4+ T cells expressing the T-cell receptor (TCR) V alpha 2.3 gene segment and a particular HLA type (DR3[17],DQ2). For purposes of comparison, we have in this study investigated TCR V gene usage and gamma delta TCR expression in CD4+ and CD8+ T cells in bronchoalveolar lavage (BAL) fluid and peripheral blood in an ethnically distinct and homogenous group of individuals consisting of Japanese sarcoidosis patients and healthy controls. We used a panel of 13 monoclonal antibodies (Mab) specific for different TCR V genes, which altogether stained approximately 50% of the T cells, and triple staining techniques with flow cytometry. The patients and controls were also HLA-typed. Our results show a high degree of expression of gamma delta TCR in peripheral blood T cells of close to half of the patients. Expansions of T-cell subsets were readily detected in the CD8+ T-cell population, while a more homogenous staining pattern was found in the CD4+ T-cell population. These findings show the importance of ethnic origin and environment in discussions of TCR V gene usage.