The Role of Cytotoxic T Lymphocytes in the Pathogenesis of Vogt-Koyanagi-Harada Disease

Peripheral blood lymphocytes (PBL) were isolated from blood of 6 patients with Vogt-Koyanagi-Harada disease (VKH), and their cytotoxic activity was assayed using 51Cr release from the labelled cells; the cytotoxicity was expressed as percentage release in reference to the complete release using saponin. The PBLs from the patients showed a significant cytotoxic activity against P-36 human melanoma cells, and the specificity of the reaction was confirmed by the cold target inhibition test and also by the use of HeLa-S3 human cervical carcinoma cells and B-16 mouse melanoma cells, since no significant cytotoxicity was seen against these cells. The cytotoxic activity was greatly reduced by pretreatment of the PBLs with monoclonal antihuman Leu-1 antibody plus the rabbit complement. It was, therefore, thought that the cytotoxic activity against the melanoma cells is mainly due to T cells. In addition, the cytotoxic activity was specifically blocked by monoclonal antihuman Leu-2a antibody, the specificity of which is distributed on cytotoxic/suppressor T cell subset of normal human peripheral lymphocytes and normal human thymocytes. A possibility was discussed as regards the involvement of the cytotoxic T lymphocytes in the pathogenesis of VKH.