The presence of specific phenotypes of intraepithelial lymphocytes (IEL) was determined in healthy and diseased gingiva by immunohistochemistry. The cutaneous lymphocyte antigen (CLA) and the alpha IEL beta 7 integrin were detected with the HECA-452 and with the HML-1 monoclonal antibodies, respectively. Some 24-62% of CD3-positive intraepithelial lymphocytes expressed the CLA antigen in the junctional epithelium, while 49-54% expressed the alpha IEL beta 7 integrin. Similar results were obtained in the other gingival epithelia. The fraction of CLA-positive T cells and alpha IEL beta 7 integrin-positive T cells was significantly higher in the gingival epithelia than in the underlying connective tissue, indicating that the T-cell subsets defined by these surface adhesion molecules were selectively localized in the epithelial compartment. Comparison of the fractions of CLA-positive and alpha IEL beta 7 integrin-positive T cells across different disease groups did not show significant differences. The data indicate that intraepithelial lymphocytes expressing the CLA and the alpha IEL beta 7 phenotype are a quantitatively important component of gingival intraepithelial immunity. These adhesion molecules may play a part in the retention of specific T-cell subsets in gingival epithelia.