Coculture of CD8⁺ T cells with CD14⁺ cells induced degranulation and IFN-γ production in HAM/TSP patients. CD107a/IFN-γ expression in CD8⁺ T cells was compared among total PBMCs, isolated CD8⁺ T cells, and coculture of isolated CD8⁺ T cells with autologous CD4⁺ T cells or CD14⁺ cells of HAM/TSP patients. The isolated CD8⁺ T cells were cocultured with autologous CD4⁺ T cells or CD14⁺ cells at the ratio of 1:0.5 or 1:1. The amount of CD107a/IFN-γ expression of CD8⁺ T cells in isolated CD8⁺ T cells and CD8⁺ T cells cocultured with CD4⁺ T cells or CD14⁺ cells were normalized to total PBMC (100%). The graph was prepared from data obtained from 5 HAM/TSP patients. Error bars represent SD.