CD8+ Tregs kill pathogenic cells to avert autoimmunity

Mouse Ly49+CD8+ regulatory T cells (Tregs) can subdue autoreactive CD4+ T cells to suppress autoimmunity. Recently, Li et al. demonstrated that killer-cell immunoglobulin-like receptor (KIR)+CD8+ T cells are the human equivalent of Ly49+CD8+ regulatory T cells and kill pathogenic CD4+ T cells, which can be increased in certain human autoimmune diseases and viral infections.