Interrelationship between bronchoalveolar lavage cellular constituents and pulmonary functions in sarcoidosis.

Bronchoalveolar lavage (BAL) using a fiberoptic bronchoscope was done in 36 patients with sarcoidosis on 45 occasions and in 19 control subjects over a period of seven years. Total cell, polymorphonuclear cell and eosinophil cell counts of bronchoalveolar lavage fluid (BALF) in patients with sarcoidosis were not significantly different from control subjects. However, lymphocyte count (% total cells) in BALF was significantly higher (P less than 0.001) in patients with sarcoidosis as compared to control subjects. Alveolar macrophage was the predominant cell type in BALF in control subjects. A significant positive correlation (r = 0.46; P less than 0.01) between vital capacity (VC) and pulmonary diffusing capacity (DLCO) and a negative correlation (r = -0.52; P less than 0.001) between BAL fluid lymphocytes (%) and DLCO (per cent predicted) was found in patients with sarcoidosis. An increase in lymphocytes in BALF is considered to be one of the parameters indicating activity of sarcoidosis. In view of the relationship between this parameter and the reduction in DLCO, the latter may also be an indicator of disease activity.