Lymphocytes obtained by bronchoalveolar lavage (BAL) in hypersensitivity pneumonitis (HP) and pulmonary sarcoidosis (PS) are believed to be derived from interstitial inflammatory lesions of the lung in which lymphocytes have migrated from the blood. Because cellular motility is one of the important factors in lymphocyte migration, we investigated the motility of BAL lymphocytes from 12 patients with HP and 12 with PS, as well as their responsiveness to chemoattractants in vitro by modified Boyden chamber method. Motility was evaluated by the number of migrated cells and the migration distance. The numbers of migrated BAL lymphocytes from patients with HP and PS in albumin-containing medium were 318.3 +/- 93.0 (mean +/- SD) and 207.6 +/- 35.5, respectively, and were greater than those of BAL lymphocytes from normal control subjects (133.3 +/- 40.9) and blood lymphocytes, and comparable with those of mitogen-activated blood lymphocytes. The motility of BAL lymphocytes in these diseases compared with blood lymphocytes was also increased in protein-free medium. In addition, the culture supernatants of alveolar macrophages (AM) enhanced the motility of BAL, mitogen-activated, and blood lymphocytes. These results suggest that BAL lymphocytes in these diseases are functionally motile, and their enhanced motility, as well as mediators from AM, may facilitate the accumulation of lymphocytes at the epithelial surface.