[Presence of filamentary secretory granules in the mucous cells of human bronchial glands].

Secretory granules containing 6-8 nm fine filaments are described in mucous cells of human bronchial glands. In contrast with the strongly marked classical mucous granules, filamentary granules exhibit weak positivity with Thiéry's method providing an easy characterization. Exocytosis in glandular lumen are often observed. These undescribed filaments may probably represent an usual component of fibrillar matrix in bronchial mucus.