Light and electron microscopic study of cyclosporin A-induced gingival hyperplasia

Four transplant (3 kidney, 1 bone marrow) patients with cyclosporin A (CyA)-induced gingival hyperplasia are described. Light and electron microscopic findings of gingival biopsies showed in all patients that, in addition to an increase of collagen, CyA induced in the subepithelial space an enormous infiltration of morphologically normal plasma cells in different stages of maturation. These data, together with the reversibility of the lesion upon discontinuation of the drug, suggest that individual hypersensitivity is probably the most acceptable explanation of CyA-induced gingival hyperplasia. This hypothesis is also discussed in relation to the CyA-suppression of the functions of some T-lymphocyte subsets.