Two-color flow cytometric analysis of activated T lymphocytes in aqueous humor of patients with endogenous vs. exogenous uveitis

To investigate the immunopathologic role of lymphocytes in aqueous humor of patients with uveitis, we assessed activated T lymphocyte subsets stained with fluorescein isothiocyanate-labeled and phycoerythrin-labeled monoclonal antibodies in aqueous humor and in peripheral blood, using two-color flow cytometry. We divided our 25 patients into those with endogenous or exogenous uveitis. The percentages of activated T lymphocytes in uveitic aqueous humor significantly exceeded those in peripheral blood lymphocytes from patients with either disease form. CD4+HLA-DR+ lymphocytes were predominant in endogenous uveitic aqueous humor, whereas CD8+HLA-DR+ lymphocytes predominated in exogenous uveitic aqueous humor in the early stage of the disease. The percentages of CD4+HLA-DR+ lymphocytes tended to increase while those of CD8+HLA-DR+ cells tended to decrease in aqueous humor from patients in the late phase of exogenous uveitis. Our results may contribute to increasing diagnostic accuracy in patients with uveitis and to developing more rational methods of treatment.