Characterization of mononuclear cells in cyclosporin A induced gingival enlargement.

Gingival biopsies from five patients with cyclosporin A (CsA) induced enlargement of the gingiva contained prominent mononuclear infiltrates beneath the epithelial basement membrane. These infiltrates and surrounding tissues were studied using monoclonal antibodies directed against lymphocytes and their subgroups (OKT 3, OKT 4, OKT 8, Leu 3 and Leu 4), monocytes (OKM 1) and the framework structure of HLA-DR antigens (OKI al). As revealed by the reactivity of these antibodies the vast majority of the mononuclear cells in two individuals consisted of monocytes and in the others of T-lymphocytes. Virtually no B-lymphocytes were observed. The ratio between T-cells bearing T 4 and T 8 antigens, in separate biopsies, varied between 6 and 0.3. Control biopsies were obtained from the gingiva of seven healthy individuals without gingivitis. These biopsies contained relatively few mononuclear cells all of which had T-lymphocyte phenotype.