Indeed, T cell dysfunction occurring alongside CLL is well documented (reviewed in Hamblin & Hamblin, 2008), and includes an increase in absolute CD4+ and CD8+ T cell numbers, inversion of CD4/CD8 T cell ratio (Mackus et al, 2003), increase in death receptor expression (Tinhofer et al, 1998), loss of costimulatory molecules necessary for stimulation of antigen-presenting cells (APCs) (Frydecka et al, 2004), abnormal cytokine/receptor profile (Scrivener et al, 2003) and impaired formation of the immune synapse (Ramsay et al, 2008). This evidence concerns the gene CD4 and B-cell chronic lymphocytic leukemia.