[Ultrastructural relief of unaffected mucosa in recurrent oral ulcer patients. 2].

Electron microscopy was performed on clinically normal vestibular mucosa biopsies of two patients affected with recurrent oral ulcers. Apoptotic cells were absent from vestibular mucosa; this is in contrast with the pathogenetic theory proposed by Honma et al., 1985 (1). Only a few modifications in the keratinization process (intracytoplasmic desmosomes, electrondense granules in basal keratinocytes) and an unusually high number of dendritic cells were found; dendritic cells could be involved in local immunological iperreactivity, responsible for the ulcers of these subjects.