Quantitative electron microscopy microscopical analysis of leukocyte infiltration in oral ulcers of Behçet's syndrome.

A stereological electron microscopical technique was applied to biopsies of oral ulcers from patients with Behçet's syndrome in order to carry out a quantitative analysis of the cellular infiltrate. The results have confirmed the light microscopical qualitative findings of a large number of lymphocytes (67%) but have established that a relatively large proportion of the leukocytes (14%( belong to the monocyte-macrophage series. The virtual absence of plasma cells during the early stages of ulceration and the presence of a large number of lymphocytes and monocytes argue in favour of a type IV cell-mediated immune reaction. As the lesion progresses a type III reaction develops and this might be associated with immune complexes found in the serum of patients with Behçet's syndrome.