The dynamic changes of the lymphocyte subsets in the inflamed ocular tissue in Lewis rats with experimental autoimmune uveitis (EAU) were studied by immunohistopathological evaluation at varying intervals after initiation of the disease. Monoclonal antibodies to specific markers of the rat T-helper/inducer lymphocyte (W3/25) and T-suppressor/cytotoxic lymphocyte (OX-8) were used in the avidin-biotin-peroxidase complex (ABC) method. During the early stages of the disease following the acute inflammatory reaction, the T-helper/inducer lymphocytes are found in larger numbers within the infiltrates, the relative number of the T-suppressor/cytotoxic cells is very low during the initial phases, with a ratio as low as 5 to 1. During the later stages, there is a continuous increase in the relative number of suppressor/cytotoxic cells that reaches the ratio of 1 to 1, or even 1 to 2. It is postulated that the observed changes in the ratios between T-helper/inducer and T-suppressor/cytotoxic cells during the different stages of EAU may reflect the kinetics and regulation of the inflammatory response in autoimmune diseases.