T-lymphocyte subset changes in recurrent aphthous stomatitis.

Immunocytochemical techniques using monoclonal antibodies directed against T-lymphocyte surface antigens (OKT3, OKT4, and OKT8) were used to investigate changes in the T-cell subpopulations throughout the natural time course of recurrent aphthous stomatitis (RAS). All lesions contained large numbers of OKT3-positive T cells. Preulcerative lesions were characterized by many OKT4-positive inducer/helper cells and few OKT8-positive suppressor/cytotoxic cells (T4:T8 approximately equal to 2:1). The ulcerative lesion contained large numbers of OKT8-positive suppressor/cytotoxic cells and only a very small number of OKT4-positive cells (T4:T8 approximately equal to 1:10). The healing lesion once again became dominated by OKT4-positive cells, with only a small number of OKT8 positive cells present (T4:T8 approximately equal to 10:1). The results support the role of lymphocytotoxicity in the establishment of the RAS lesion and may suggest a local immunoregulatory imbalance. NK cells, Leu-7 positive, were also identified in the preulcerative lesions and very early ulcerative lesions.