In keeping with this, multiple abnormalities of circulating T-cells have been described in CLL, including a reduced CD4:CD8 ratio (1), increased regulatory T-cells (2, 3), increased differentiation towards antigen-experienced and terminally differentiated memory cells (4, 5), and increased expression of activation and exhaustion (5–7) markers. This evidence concerns the gene CD4 and B-cell chronic lymphocytic leukemia.