In the recent years, several reports suggested an active anti-leukemia immunity by CD8+ T-cells, as TCR analyses of CLL blood samples or spleens of TCL1 AT mice revealed an enrichment of clonally expanded CD8+ T-cells [49, 83–85] with the major clonotypes persisting for about 2 years in patients [83]. The gene discussed is CD8A; the disease is B-cell chronic lymphocytic leukemia.