The ultrastructure of T and B lymphocytes in recurrent apthous ulceration of the buccal mucosa.

The purpose of the present study was to classify lymphocytes in the buccal mucosa of patients affected with recurrent apthous ulceration. Two lymphocytes were identified. The B lymphocyte was characterized by an extensive Golgi complex, an extensive tubular rough surfaced endoplasmic reticulum, and an extensive canalicular system. Usually the nucleus was electron lucent except for perinuclear condensation of chromatin. The T lymphocyte had a moderately developed Golgi complex, absent or poorly developed rough surfaced endoplasmic reticulum, lysosomes, and considerably more heterochromatin (perinuclear) than the B lymphocyte. Uropods were associated with the T lymphocyte and exerted cytotoxic effects on basal and suprabasal cells.