Oral lesions in lichen planus and systemic lupus erythematosus. A histochemical and immunohistochemical study.

The present study aimed to characterize and compare the inflammatory cells in the oral lesions in lichen planus and systemic lupus erythematosus. The inflammatory cell subtypes were identified by the combined use of morphological criteria and intracellular markers. In lichen planus 70-90% of all lymphocytes in a band-like submucosal infiltrate were acid alpha-naphthyl acetate esterase (= ANAE)-positive T lymphocytes. The lymphocyte band was sandwiched between mature tissue macrophages and plasma cells. In systemic lupus erythematosus (SLE) the lymphoid cell infiltrate pattern was more variable with extension of the infiltrate to the deeper connective layers and with a more patchy arrangement. The number of ANAE-negative (B) lymphocytes equalled the numbers of ANAE-positive T lymphocytes. In addition, large numbers of plasma cells were present in some lupus patients. In both diseases IgG was produced by 80% of all plasma cells in situ and there were equal portions of cells containing kappa and lambda light chains.