TYR and Huntington disease: In five of nine HD tested, the tyrosinase-specific CD8 + T cells were predominantly stem cell-like T cells (SC: IL-2+/IFN-γ−, TNF-α− and GzB−), and outnumbered the polyfunctional (PF: IL-2+/ IFN-γ+, TNF-α+ and GzB+) and terminal effector cells (TE: IL-2−/ IFN-γ+, TNF-α+ and GzB+) by at least twofold.