T-cell receptor V gene expression in HLA-typed Japanese patients with pulmonary sarcoidosis

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.