[The ultramicrostructure of secretory granules of mast cells in giant papillae of vernal keratoconjunctivitis patients].

PURPOSE: To investigate the subtypes, extent of activation, and method of degranulation of mast cells (MCs) by observation of the ultramicrostructure of secretory granules from MCs in the giant papillae (GP) of patients with vernal keratoconjunctivitis (VKC).

METHODS

After informed consent, 8 giant papillae were obtained from 6 patients with severe VKC during treatment. The 168 collected MCs were observed by electron microscopy.

RESULTS

Thirty-eight percent of the MCs were degranulated (17% piecemeal and 21% anaphylactic degranulation). Among the non-degranulated MCs, 13% were TC type cells containing dense amorphous granules; 9% were T type cells containing scroll granules; 15% were transient cells containing both amorphous and scroll granules; and 25% were activated MCs containing particulate granules. Three patterns (separation from the cell membrane, exocytosis, and dissolution) of granule release were recognized.

CONCLUSION

The dynamics of MCs in GP were assessed from the ultramicrostructure of the secretory granules.