[Bronchoalveolar lavage in sarcoidosis]

A characteristic feature of BAL in patients with sarcoidosis is an increase of the total cell number, lymphocytes percent, or CD4/CD8 ratio of T lymphocytes. With respect to T lymphocytes, sarcoidosis has been recognized as a granulomatous disease characterized by dominant expression of Th1 cytokines. Recently Th1 cytokine profile in both CD4+ and CD8+ T lymphocytes in BAL fluid were demonstrated at the single-cell level. Furthermore, alveolar macrophages collected from BAL fluid were also investigated. Increased expression of 25-hydroxyvitamin D3 1 alpha-hydroxylase with mRNA level in alveolar macrophage were revealed in active sarcoidosis. Previously we showed that the B allele of the vitamin D receptor gene polymorphism may be regarded as a risk factor in the onset of sarcoidosis. The metabolism of vitamin D may be related to granuloma formation.