Leukocytes and mast cells have been described in the human nasal mucos
a and epithelium of the lower airways (Bonneville 1988, Goodman and Le
francois 1989, Guy-Grand 1991, Denburg 1992). In mast cells, heterogen
eity of mucosal and connective tissue mast cells has been observed. In
the present electron microscope study, the epithelium of the upper ai
rways (larnyx and nose) of patients suffering from chronic laryngitis,
was examined with special regard to intraepithelial mast cells. Numer
ous mast cells were found in the stratum spinosum of the true vocal co
rds showing extensive elongated surface folds that had little contact
to epithelial cells. Desmosomes were absent Mucosal mast cells are cha
racterised by four types of membrane-bounded granules, whereas serosal
mast cells only showed two different types of granules and resembled
blood basophiles. Migration of connective tissue mast cells into the e
pithelium could not be observed. According to our findings mucosal and
mast cells belong to different cell lines.