[Leukoplakia and cancers of the buccal cavity. Immunofluorescence counting and typing of plasmocytes].

Immunofluorescent study of paraffin sections of 80 lesions of the buccal cavity, for the most part malignant or pre-malignant revealed marked plasmocytosis in premalignant or early malignant cases. This plasmocytosis, easily seen by the use of anti-immunoglobulin sera, is of polyclonal type, with marked preponderance of IgG secretors. In infiltrating carcinomas and in recurrences, the number of plasmocytes decreases and the percentage of IgG secretors falls markedly. By contrast, that of IgA immunocytes remains the same. The significance of these findings is considered and their practical value in the surveillance of cases of leukoplasia is stressed.